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Sample records for platinum palladium lead

  1. Determination of platinum, palladium, and lead in biological samples by atomic absorption spectrophotometry.

    Science.gov (United States)

    Tillery, J B; Johnson, D E

    1975-01-01

    A flameless atomic absorption method for the coextraction of platinum and palladium from biological and environmental samples by high molecular weight amine (HMWA) is given. Also, methods for lead determination in biological samples by use of extraction flameless analysis and direct aspiration-flame analysis are reported. A study of lead contamination of Vacutainer tubes is given. PMID:1227857

  2. Platinum- and platinum alloy-coated palladium and palladium alloy particles and uses thereof

    Science.gov (United States)

    Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir Branko

    2010-04-06

    The present invention relates to particle and nanoparticle composites useful as oxygen-reduction electrocatalysts. The particle composites are composed of a palladium or palladium-alloy particle or nanoparticle substrate coated with an atomic submonolayer, monolayer, bilayer, or trilayer of zerovalent platinum atoms. The invention also relates to a catalyst and a fuel cell containing the particle or nanoparticle composites of the invention. The invention additionally includes methods for oxygen reduction and production of electrical energy by using the particle and nanoparticle composites of the invention.

  3. A fire-assay and wet chemical method for the determination of palladium, platinum, gold, and silver in ores and concentrates.

    Science.gov (United States)

    Moloughney, P E

    1980-04-01

    A method is presented for the determination of palladium, platinum, gold and silver in ores and concentrates by a fire-assay and wet chemical technique. After parting of the lead assay button with dilute nitric acid, and separation of the solution from the residue, the palladium and platinum in the solution are precipitated by the addition of stannous chloride, with tellurium as collector. The resulting precipitate is combined with the gold residue and dissolved in aqua regia, then the solution is analysed for palladium, platinum and gold by atomic-absorption spectrophotometry (AAS). Silver is determined in the original solution by AAS before the reduction step.

  4. Extraction of gold, palladium, and platinum from acidic media with cyclic sulfoxide derivative

    Institute of Scientific and Technical Information of China (English)

    Songping Wu; Guobang Gu

    2007-01-01

    The extraction of gold (Ⅲ), palladium (Ⅱ), and platinum (Ⅳ) from the acidic media with the cyclic sulfoxide derivative of a-dodecyl-tetrahydrothiophene 1-oxide (dtmso) was investigated. Gold (Ⅲ), palladium (Ⅱ), and platinum (Ⅳ) could be separated from the acidic media with suitable sulfoxide concentration and acidity. The extraction reaction of gold (Ⅲ), palladium (Ⅱ) or platinum (Ⅳ) is exothermic when dtmso is used as an extracting reagent. The coordination number was studied by the slope method. The results indicate that, in high acidity, the dtmso coordination number for extracting gold (Ⅲ) or palladium (Ⅱ) is 3, and that for platinum (Ⅳ) is 2. UV and FT-IR spectra were used to analyze the structure of the complex. Gold (Ⅲ) is coordinated with the oxygen atom in S=O group in dtmso, and palladium (Ⅱ) or platinum (Ⅳ) is coordinated with the sulfur atom in S=O group in dtmso.

  5. Bulk synthesis of nanoporous palladium and platinum powders

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, David B; Fares, Stephen J; Tran, Kim L; Langham, Mary E

    2014-04-15

    Disclosed is a method for providing nanoporous palladium and platinum powders. These materials were synthesized on milligram to gram scales by chemical reduction of tetrahalo-complexes with ascorbate in a concentrated aqueous surfactant at temperatures between -20.degree. C. and 30.degree. C. The prepared particles have diameters of approximately 50 nm, wherein each particle is perforated by pores having diameters of approximately 3 nm, as determined by electron tomography. These materials are of potential value for hydrogen and electrical charge storage applications.

  6. Bulk synthesis of nanoporous palladium and platinum powders

    Science.gov (United States)

    Robinson, David B [Fremont, CA; Fares, Stephen J [Pleasanton, CA; Tran, Kim L [Livermore, CA; Langham, Mary E [Pleasanton, CA

    2012-04-17

    Disclosed is a method for providing nanoporous palladium and platinum powders. These materials were synthesized on milligram to gram scales by chemical reduction of tetrahalo-complexes with ascorbate in a concentrated aqueous surfactant at temperatures between -20.degree. C. and 30.degree. C. The prepared particles have diameters of approximately 50 nm, wherein each particle is perforated by pores having diameters of approximately 3 nm, as determined by electron tomography. These materials are of potential value for hydrogen and electrical charge storage applications.

  7. Investigation of mechanical and structural characteristics of platinum and palladium at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Trumie, B. T.; Gomidzelovie, L.; Marjanovic, S. R.; Krstic, V. R.

    2015-03-30

    In order to broaden future application of products based on platinum and palladium a comparative analysis of their high-temperature mechanical properties was performed. Platinum and palladium are of great importance and are widely used in chemical industry, electronics, for making laboratory dishes, to name a few. Mechanical properties of pure metals, such as: tensile strength, creep rate and rupture time were investigated using universal testing machine for tensile testing of materials. Microstructure of samples was investigated by optical microscopy. Based on obtained results it can be concluded that the platinum, compared to palladium, is superior for high-temperature applications. (Author)

  8. Platinum(II), palladium(II), rhodium(III) and lead(II) voltammetric determination in sites differently influenced by vehicle traffic.

    Science.gov (United States)

    Melucci, Dora; Locatelli, Clinio

    2007-01-01

    The present work reports analytical results relevant to voltammetric determination of Pt(II), Pd(II), Rh(III) [Platinum Group Metals (PGMs)] and Pb(II) in superficial water sampled in sites differently influenced by vehicle traffic, especially considering their temporal behaviour. For all the elements, in addition to detection limits, precision, expressed as relative standard deviation (s(r) %) and accuracy, expressed as percentage recovery (R %) are also reported. In all cases they show to be good, being the former lower than 6% and the latter in the range 94-105%. A critical comparison with spectroscopic measurements is also discussed.

  9. Determination of Trace Platinum, Palladium and Gold in Geochemical Samples by Emission Spectrometry With Lead Fire Assaying Concentration%铅火试金富集-发射光谱法测定化探样品痕量金、铂和钯

    Institute of Scientific and Technical Information of China (English)

    陈春军; 钟宁

    2014-01-01

    试样用铅火试金富集铂组元素及金,加入1 mg银,在950℃熔融得到含贵金属的铅扣。铅扣与熔渣分离后在900℃灰吹得含铂、钯和金的银合金粒。把合金粒装入电极,以发射光谱法同时测定铂、钯和金的含量。%Platinum group elements and gold in sample were enriched by lead fire assaying, after adding 1 mg silver and melting at 950 ℃, lead button containing precious metals was obtained. Then lead button was separated from slag, silver grains containing platinum, palladium and gold were obtained by soot blowing at 900 ℃. Putting the alloy grain into the electrode, contents of platinum, palladium and gold were simultaneously determined by the emission spectrometry.

  10. Green Synthesis, Characterization and Uses of Palladium/Platinum Nanoparticles

    Science.gov (United States)

    Siddiqi, Khwaja Salahuddin; Husen, Azamal

    2016-11-01

    Biogenic synthesis of palladium (Pd) and platinum (Pt) nanoparticles from plants and microbes has captured the attention of many researchers because it is economical, sustainable and eco-friendly. Plant and their parts are known to have various kinds of primary and secondary metabolites which reduce the metal salts to metal nanoparticles. Shape, size and stability of Pd and Pt nanoparticles are influenced by pH, temperature, incubation time and concentrations of plant extract and that of the metal salt. Pd and Pt nanoparticles are broadly used as catalyst, as drug, drug carrier and in cancer treatment. They have shown size- and shape-dependent specific and selective therapeutic properties. In this review, we have discussed the biogenic fabrication of Pd/Pt nanoparticles, their potential application as catalyst, medicine, biosensor, medical diagnostic and pharmaceuticals.

  11. Chemistry of Platinum and Palladium Metal Complexes in Homogeneous and Heterogeneous Catalysis: A Mini Review

    Directory of Open Access Journals (Sweden)

    Mehrban Ashiq

    2013-04-01

    Full Text Available Transition metal complexes of platinum and palladium are most widely used in catalysis. Many synthetic reactions have been carried out with such complexes (used as a catalyst which have specifically polymer ligands, through hydrosilylation, acetoxylation, hydrogenation, hydro-formylation, oligo-merisation and polymerization. Almost many platinum and palladium catalysts are heterogeneous in nature i.e. the reaction taking place on a solid surface. Now from few years homogeneous catalysts which are completely soluble in the liquid phase reactant, has acknowledged too much attention, yet having small industrial applications, mainly due to the striving of platinum and palladium complexes separation from the catalytic products. More recently a transitional type of platinum and palladium catalysts have been synthesized through attachment of the activated transition metal complexes on the surface of polymer support particularly insoluble which has been establish to offer encouraging new collection of catalysts for effective research on synthesis. Many of such complexes will be based on the palladium and platinum metals group. The major objective of this review is to inaugurate the relationship among the reactivity’s of homogeneous platinum and palladium complexes and heterogeneous complexes of these metals (those bonded to the surface of metals.

  12. Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aquesous Solution

    Institute of Scientific and Technical Information of China (English)

    张小玲; 阎宏涛

    2002-01-01

    A selective and sensitive method for determination of platinum and palladium(Ⅱ)in an aqueous solution simultaneously by laser thermal lens spectrometry,based on the complex reaction of 2-(3,5-dichloropyridylazo)-5-dimethylaminoamiline(3,5-diCl-PADMA) with platinum and palladium,has been developed.It is shown that the palladium complex can be fromed at room temperature, while the platinum complex can be only formed after being heated in a boiling water bath.By using this difference of reaction temperature and the characteristic of the complexes mentioned above,the method for simultaneous determination of platinum and palladium was established in an aqueous solution without a pre-separation.The results show that the dynamic linear ranges of determination for platinum and palladium are 0.005-0.04μg/mL and 0.005-0.25μg/mL respectively,and that the detection limits are both 0.002/μg/mL.The method has been applied to the determination of platinum and palladium simultaneously in alloy and catalyst samples with satisfactory results.

  13. Palladium and platinum-palladium bi-layer based counter electrode for dye-sensitized solar cells with modified photoanode

    Science.gov (United States)

    Mokurala, Krishnaiah; Kamble, Anvita; Nemala, Siva Sankar; Bhargava, Parag; Mallick, Sudhanshu

    2015-06-01

    Dye sensitized solar cells (DSSCs) were fabricated with palladium (Pd) and platinum-palladium (Pt-Pd) bi-layer as counter electrodes, respectively. Effects of photoanode thickness and morphology on device performance were studied. DSSCs fabricated with Pd and Pd-Pt as counter electrode (CE) showed photo conversion efficiency of 4.30% and 6.20%, respectively as compared to Platinum (Pt) based CE which showed 6.65% efficiency. Lower device performance was explained with help of cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements of the cells.

  14. [Simultaneous determination of platinum (IV) and palladium (II) using spectrophotometry method].

    Science.gov (United States)

    Ma, Dong-Lan; Wang, Yun; Ma, Kuang-Biao; Wang, Jin-Ye

    2009-10-01

    The N-(m-methylphenyl)-N'-(sodium p-aminobenzenesulfonate)-thiourea (MMPT) was good reagent of water solubility. In the medium of an HAc-NaAc buffer solution and hexadecyltrimethylammonium bromide (CTMAB), MMPT can react with platinum (IV) and palladium (II) to form green and brown soluble complex. The maximum absorbance of the complex was at lambdaPt(max) = 754.4 nm and lambdaPD(max) = 304.6 nm. Beer's law was obeyed with the concentration in the range of 0-32.0 microg Pt(IV)/25 mL and 0-25.0 microg Pd(II)/25 mL for platinum (IV) and palladium(II) respectively. The correlated coefficient was r754.4 = 0.999 5 for platinum (IV); and r304.6 = 0.999 9 for palladium (II). Their molar absorption coefficients were epsilonPT(754.4 = 8.6 x 10(4) L x mol(-1) x cm(-1) and epsilonPd(304.6) = 7.4 x 10(4) L x mol(-1) x cm(-1) respectively. The contents of platinum (IV) and palladium (II) were converted by determination of the absorbency of mix solution of platinum (IV) and palladium (II) at 754.4 and 304.6 nm. Only Cu2+ and Co2+ interfered with the determination of palladium (II) among 50 coexistent ions, so the selectivity was good. It can be used for the determination of content of synthesis samples. The relative standard deviation (RSD) was less than 2.0%, and the recovery (%) was in the range of 96%-104%. The results are satisfactory. Because the reagent reacts with platinum (IV) and palladium (II) to form water soluble complex and does not require pre-separation for simultaneous determination of platinum (IV) and palladium (II), the method is easy to operate, rapid and environment-friendly.

  15. Palladium and platinum organochalcogenolates and their transformation into metal chalcogenides

    Indian Academy of Sciences (India)

    S Dey; S Narayan; A Singhal; V K Jain

    2000-06-01

    Platinum group metal chalcogenides find extensive applications in catalysis and in the electronic industry. To develop an efficient low temperature clean preparation of these materials, molecular routes have been explored. Thus the chemistry of mononuclear organochalcogenolates of the type [M(ER 1/4)2(PR3)2], binuclear benzylselenolates, [M2Cl2(∼-SeBz)2(PR3)2], allylpalladium complexes [Pd2(μ-ER)2(3-C4H7)2] and palladium/platinum sulphido/selenido-bridged complexes, [M2(μ-E)2L4] (M = Pd or Pt; E = S, Se or Te; L = tertiary phosphine ligand) has been investigated. All the complexes have been characterized by elemental analysis, NMR (1 H, 31P, 77Se, 195Pt) spectroscopy and in some cases by X-ray diffraction. The thermal behaviour of these complexes has been studied by TGA. The pyrolysis of allylpalladium complexes in refluxing xylene yields Pd4E as established by analysis and XRD patterns.

  16. Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Xiao-Ling(张小玲); YAN,Hong-Tao(阎宏涛)

    2002-01-01

    A selective and sensitive method for determination of platinum and palladium(Ⅱ) in an aqueous solntion simultaneously by laser thermal lens spectrometry, based on the complex reaction of 2- (3,5-dichloropyridylazo)-5- dimethylaminoamiline (3,5-diCl-PADMA) with platinum and palladium, has been developed. It is shown that the palladium complex can be formed at room temperature, while the platinum complex can be only formed after being heated in a boiling water bath. By using this difference of reaction temperature and the characteristic of the complexes mentioned above, the method for simultaneous determination of platinum and palladium was established in an aqueous solution without a pre-separation. The results show that the dynamic linear ranges of determination for platinum and pallladium are 0.005-0.04 μg/mL and 0.005-0.25 μg/mL respectively, and that the detection limits are both 0.002 μg/mL. The method has been applied to the determination of platinum and palladium simultaneously in alloy and catalyst samples with satisfactory results.

  17. Surfactant gel adsorption of platinum(II), (IV) and palladium(II) as chloro-complexes and kinetic separation of palladium from platinum using EDTA.

    Science.gov (United States)

    Murakami, Yoshiko; Hiraiwa, Kaoru; Sasaki, Yoshiaki; Fujiwara, Isamu; Tagashira, Shoji

    2007-09-01

    A micellar solution of cetylpyridinium chloride (CPC) can separate into two phases due to a temperature change or to the addition of salts. Platinum(II), (IV) and palladium(II) reacted with chloride ions to form stable anionic complexes of PtCl4(2-), PtCl6(2-) and PdCl4(2-), respectively, and were adsorbed onto the CPC gel phase. The CPC phase plays the role of an ion-exchange adsorbent for the anionic complexes. By such a procedure, the precious metals of platinum and palladium could be separated from base metals such as copper, zinc and iron. The kinetic separation was performed by a ligand exchange reaction of the palladium(II) chloro-complex with EDTA at 60 degrees C. The anionic palladium(II)-EDTA complex could not bind the opposite charged CP+ and was desorbed from the CPC phase. In the aqueous phase, the recovery of palladium(II) by the double-desorption was 101.1 +/- 1.2%. The platinum(II) and (IV) chloro-complexes were stable for at least 30 min and remained in the CPC phase.

  18. Noble Metal Catalysts for Mercury Oxidation in Utility Flue Gas: Gold, Palladium and Platinum Formulations

    Energy Technology Data Exchange (ETDEWEB)

    Presto, A.A.; Granite, E.J

    2008-07-01

    The use of noble metals as catalysts for mercury oxidation in flue gas remains an area of active study. To date, field studies have focused on gold and palladium catalysts installed at pilot scale. In this article, we introduce bench-scale experimental results for gold, palladium and platinum catalysts tested in realistic simulated flue gas. Our initial results reveal some intriguing characteristics of catalytic mercury oxidation and provide insight for future research into this potentially important process.

  19. Mechanistic insights on platinum- and palladium-pincer catalyzed coupling and cyclopropanation reactions between olefins.

    Science.gov (United States)

    Rajeev, Ramanan; Sunoj, Raghavan B

    2012-07-21

    The mechanism of M(II)-PNP-pincer catalyzed reaction between (i) ethene, (ii) trans-butene with 2-methylbut-2-ene, 2,3-dimethylbut-2-ene and tert-butylbutene is examined by using density functional theory methods (where M = Pt or Pd). All key intermediates and transition states involved in the reaction are precisely located on the respective potential energy surfaces using the popular DFT functionals such as mPW1K, M06-2X, and B3LYP in conjunction with the 6-31+G** basis set. The reaction between these olefins can lead to a linear coupling product or a substituted cyclopropane. The energetic comparison between coupling as well as cyclopropanation pathways involving four pairs of olefins for both platinum (1-4) and palladium (5-8) catalyzed reactions is performed. The key events in the lower energy pathway in the mechanistic course involves (i) a C-C bond formation between the metal bound olefin (ethene or trans-butene) and a free olefin, and (ii) two successive [1,2] hydrogen migrations in the ensuing carbocationic intermediates (1c-4c, and 1d-4d), toward the formation of the coupling product. The computed barriers for these steps in the reaction of metal bound ethene to free tert-butylbutene (or other butenes) are found to be much lower than the corresponding steps when trans-butene is bound to the metal pincer. The Gibbs free energy differences between the transition states leading to the coupling product (TS(d-e)) and that responsible for cyclopropanated product (TS(d-g)) are found to be diminishingly closer in the case of the platinum pincer as compared to that in the palladium system. The computed energetics indicate that the coupled product prefers to remain as a metal olefin complex, consistent with the earlier experimental reports.

  20. Determination of platinum and palladium in copper leaching residue by inductively coupled plasma atomic emission spectrometry with lead fire assaying%铅试金-电感耦合等离子体原子发射光谱法测定铜浸出渣中铂钯

    Institute of Scientific and Technical Information of China (English)

    魏巍; 柴徐彬

    2015-01-01

    Platinum and palladium in copper leaching residue were captured into gold-silver composite granule by lead fire assaying method. Then, the gold-silver composite granule was dissolved with nitric acid (1+7). After the solution was pouring out, the residues were dissolved with aqua regia(1+1). Merging the solutions above, the hy-drochloric acid (1+1) was added to precipitate the silver. After filtration, the content of platinum and palladium in filtrate was determined. Thus, a method was established for determination of platinum and palladium in copper leaching residue by inductively coupled plasma atomic emission spectrometry ( ICP-AES) . The interference tests of gold and silver in gold-silver composite granule indicated that the absorption of platinum and palladium by silver chloride precipitate could be eliminated through continuous stirring in precipitation process. Meanwhile, gold in so-lution had no interference with the determination. The proposed method was applied to the determination of copper leaching residue actual samples. The relative standard deviations of the results (RSD, n=11) were 5. 6%-9. 7%, and the recoveries were between 94% and 104%. The content of platinum and palladium in control samples of cop-per leaching residue was determined by proposed method. The results were consistent with the reference values.%采用铅试金法将铜浸出渣中的铂和钯捕集于金银合粒中,用硝酸(1+7)溶解金银合粒,倾出硝酸溶解液,用王水(1+1)溶解剩余的残渣,合并两次溶解液,加入盐酸(1+1)沉淀银,过滤,对溶液中铂和钯进行测定,建立了电感耦合等离子体原子发射光谱法( ICP-AES )测定铜浸出渣中铂和钯的分析方法。金银合粒中金和银的干扰试验表明:在沉淀过程中不断搅拌可消除氯化银沉淀对铂和钯吸附的影响,同时溶液中的金对测定不产生干扰。方法用于铜浸出渣实际样品分析,测得结果的相对标准偏差(RSD,n=11)为5.6%~9.7%,

  1. Quasi-homogeneous hydrogenation with platinum and palladium nanoparticles stabilized by dendritic core-multishell architectures.

    Science.gov (United States)

    Schwarze, Michael; Keilitz, Juliane; Nowag, Sabrina; Parapat, Riny Y; Haag, Rainer; Schomäcker, Reinhard

    2011-05-17

    Platinum and palladium nanoparticles, supported and stabilized by polymeric core-shell architectures, proved to be active catalysts for hydrogenation reactions. Here, two different reactions were used as probes to investigate the influence of the polymeric support: the hydrogenation of α-methyl styrene (AMS) to cumene and the partial hydrogenation of 1,5-cyclooctadiene (COD). We found that the stability of the nanoparticles and the rate of reaction are higher in the presence of a hydrophobic octadecyl shell within a three-shell polymer system. The kinetic study of AMS hydrogenation showed much higher activities for palladium nanoparticles than for platinum nanoparticles, and the obtained results (e.g., 35 kJ/mol for the activation energy) are of the same order of magnitude as reported earlier for palladium supported on alumina. A methanol/n-heptane biphasic mixture was tested for catalyst recycling and allowed for highly efficient catalyst separation with very low metal leaching.

  2. Recovery of Platinum, Palladium and Gold from Platinum and Palladium Concentrates%从铂钯精矿中回收铂、钯和金

    Institute of Scientific and Technical Information of China (English)

    赖建林; 周宇飞; 饶红; 黄冰

    2015-01-01

    The operation process of calcinations-preleaching-chloridizing leaching-extraction-refine was applied to recover gold, palladium and platinum from copper anode mud. The results showed that after the oxidation reduction potential of chlorination liquid was controlled with sodium sulfite, the recovery rate of gold could reach 99%; while palladium was extracted from remain liquid with isoamyl sulphide, at a recover rate of over 90%. The liquid remain after the palladium extraction process was treated with trialkylamine and NaOH to reextract platinum. The treatment process could give rise to a palladium and platinum product which can be 99.99%, reached national standard of China, and the grade of coarse gold powder could be up to 97.09%.%采用焙烧-预浸出-氯化浸出-萃取-精制工艺处理铜冶炼阳极泥产出铂钯精矿回收铂、钯、金.结果表明,氯化液采用亚硫酸钠控制电位还原,金回收率99%;金还原后液采用二异戊基硫醚萃取钯,氨水反萃,钯回收率>90%;萃钯余液采用馯烷基胺萃取铂,氢氧化钠反萃,铂回收率>90%.铂、钯符合国标99.99%产品要求,粗金粉品位97.09%.

  3. An ion-exchange method for selective separation of palladium, platinum and rhodium from solutions obtained by leaching automotive catalytic converters.

    Science.gov (United States)

    Gaita, R; Al-Bazi, S J

    1995-02-01

    An ion-exchange method has been developed for the separation of palladium, platinum and rhodium from a solution that is highly acidic and contains a considerable amount of lead, aluminum, iron and cerium, obtained by leaching a used honeycomb type automotive catalytic converter. A column of Amberlite IRA-93 anion-exchange resin was found appropriate to recover platinum metals from the pregnant solution. Selective stripping of these metals from the resin was achieved by eluting rhodium first with 6.0M hydrochloric acid, then palladium with a 1% ammonia solution at ambient temperature, and platinum with 5% of the reagent at elevated temperatures. Optimum conditions for leaching these metals from the catalyst were 5.0M hydrochloric acid and 0.4M sodium chlorate at 70 degrees C. This method can be applied to both analytical as well as large scale operations. It is simple, economical, and relatively safe for human exposure and the environment.

  4. Stripping voltammetric determination of palladium, platinum and rhodium in freshwater and sediment samples from South African water resources

    CSIR Research Space (South Africa)

    Van der Horst, C

    2012-08-01

    Full Text Available of platinum (Pt2+), palladium (Pd2+) or rhodium (Rh2+) by means of adsorptive cathodic stripping voltammetry. Optimised experimental conditions included composition of the supporting electrolyte, complexing agent concentration, deposition potential, deposition...

  5. 从铂钯精矿中提取金、铂、钯工艺研究%Research on Extraction of Gold, Platinum and Palladium From Palladium-Platinum Concentrate

    Institute of Scientific and Technical Information of China (English)

    王兴; 崔家友; 张善辉; 陶明光

    2015-01-01

    针对在处理铜阳极泥过程中产生的铂钯精矿,采用电控除杂-大氯化溶解Au、Pt、Pd-氯化铵共沉铂钯-SO2还原金-水煮分离铂钯-铂钯精炼工艺提取金、铂、钯。铂、钯回收率98%以上,金的回收率为99%。该工艺具有成本低、操作简单、贵金属回收率高等优点。%In connection with the Platinum and Palladium Concentrates produced in the course of processing copper anode slime, utilizing the process of electronically controlled impurity-large chloride dissolving gold, platinum, palladium-ammonium chloride coprecipitating platinum and palladium-SO2 restoring gold-separation platinum and palladium by boiling to refine platinum and palladium. The recovery rate of platinum and palladium is over 98%, the recovery rate of gold reaches to 99%. The process has the advantage of low cost , simple operation, high precious metals recovery.

  6. Epitaxial and non-epitaxial platinum, palladium and silver films on yttrium-stabilised zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Gesa, E-mail: gesa.beck@physik.uni-augsburg.de [Institute of Physics, University Augsburg, Universitaetsstrasse 1a, 86159 Augsburg (Germany); Bachmann, Christoph [Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen (Germany); Bretzler, Rita [Research Institute Precious Metals & Metals Chemistry, Katharinenstrasse 17, 73525 Schwaebisch Gmuend (Germany); Kmeth, Ralf [Institute of Physics, University Augsburg, Universitaetsstrasse 1a, 86159 Augsburg (Germany)

    2015-05-05

    Platinum, palladium and silver films have been prepared on differently orientated YSZ (yttrium-stabilised zirconia) substrates by PLD (pulsed laser deposition). The deposition temperatures for platinum were 200 °C and 400 °C, whereas palladium and silver were deposited only at 200 °C. The microstructure of the films depends on the particular metal, on the orientation of the substrate and on the deposition temperature. Platinum – deposited at 400 °C – forms single crystalline, epitaxial (111), (311) and (110) orientated as well as (111) orientated polycrystalline films. Platinum, palladium and silver – deposited at 200 °C – always form (111) orientated and polycrystalline films, in some cases also with a fraction of epitaxial grown grains. The formed microstructures were discussed on the basis of interface and surface energy minimization and structure zone models. - Highlights: • Pt, Pd and Ag films are prepared on differently orientated YSZ. • Substrate orientation and deposition temperature influences the microstructure. • Pt forms epitaxial and polycrystalline films. • Pd and Ag form polycrystalline films, sometimes with epitaxial grown grains. • The formed microstructures are described by energy minimization.

  7. Chemical composition of the ore and occurrence state of the elements in Jingbaoshan platinum- palladium deposit

    Institute of Scientific and Technical Information of China (English)

    SONG Huanbin; HE Mingqin; ZHANG Shangzhong; YI Fenghuang

    2008-01-01

    The Jingbaoshan platinum-palladium deposit is China's largest independent PGM (platinum-group metals) deposit so far discovered. There are eleven kinds of useful components in the ore: Pt, Pd, Os, Ir, Ru, Rh, Au, Ag, Cu, Ni, and Co. The platinum-group elements, gold and silver occur in the form of minerals in ores. twenty-five kinds of precious metal minerals have been found, of which twenty one belong to the platinum-group minerals. The minerals are very small in grain size. Copper occurs mainly as copper sulfide with a small amount of free copper oxide, and the beneficiated copper accounts for 95.21%. Nickel occurs mainly as nickel sulfide, and some nickel silicate and nickel oxide occur in the ore. The beneficiated nickel accounts for 72.03%. Cobalt occurs mainly as cobalt sulfide, and there are some cobalt oxide and other kinds of cobalt. The beneficiated cobalt accounts for 77.58%.

  8. Do Scarce Precious Metals Equate to Safe Harbor Investments? The Case of Platinum and Palladium

    Directory of Open Access Journals (Sweden)

    John Francis T. Diaz

    2016-01-01

    Full Text Available This research establishes the predictability and safe harbor properties of two scarce precious metals, namely, platinum and palladium. Utilizing their spot prices, the study concludes intermediate memory in the return structures of both precious metals, which implies the instability of platinum and palladium returns’ persistency in the long run. However, both the ARFIMA-FIGARCH and the ARFIMA-FIAPARCH models confirm long-memory properties in the volatility of the two spot prices. The leverage effects phenomenon is not also present based on the ARFIMA-APARCH and ARFIMA-FIAPARCH models, which may possibly conclude the resilience of both precious metals against increased volatility. However, further tests proved that only platinum has a symmetric volatility response to shocks with the presence of negative gamma parameter, which proves that only platinum can be considered a safe harbor investment, because negative and positive shocks have equal effects on their returns and volatilities. Comparing the four models utilized in this study, the combined ARFIMA-FIAPARCH models are the best fitting model to characterize both precious metals’ spot prices.

  9. A comparison of the marginal and internal adaptation of titanium and gold-platinum-palladium metal ceramic crowns.

    Science.gov (United States)

    Valderrama, S; Van Roekel, N; Andersson, M; Goodacre, C J; Munoz, C A

    1995-01-01

    The marginal and internal adaptation of metal ceramic crowns fabricated by electrical discharge machining and conventional metal ceramic alloys were compared. The crowns were cemented using zinc phosphate cement, embedded in epoxy resin, and sectioned in two planes: diagonal and buccolingual. The crowns were then measured at nine sites. The results showed that there were no statistical differences between the external marginal opening of the titanium and the gold-platinum-palladium crowns. The overall marginal discrepancies for the restorations in this study were 61 microns (+/- 34 microns) for the titanium metal ceramic crowns and 47 microns (+/- 17 microns) for the gold-platinum-palladium metal ceramic crowns.

  10. Investigation of mechanical and structural characteristics of platinum and palladium at high temperatures

    Directory of Open Access Journals (Sweden)

    Trumic, Biserka T.

    2015-03-01

    Full Text Available In order to broaden future application of products based on platinum and palladium a comparative analysis of their high-temperature mechanical properties was performed. Platinum and palladium are of great importance and are widely used in chemical industry, electronics, for making laboratory dishes, to name a few. Mechanical properties of pure metals, such as: tensile strength, creep rate and rupture time were investigated using universal testing machine for tensile testing of materials. Microstructure of samples was investigated by optical microscopy. Based on obtained results it can be concluded that the platinum, compared to palladium, is superior for high-temperature applications.Se realiza un estudio comparativo de las propiedades mecánicas a alta temperatura del platino y paladio, con el fin de ampliar las aplicaciones de los productos basados en estos metales. El platino y el paladio son de gran importancia y se utilizan ampliamente en la industria química, electrónica y para la fabricación de placas de laboratorio, entre otras aplicaciones. Se estudiaron las siguientes propiedades mecánicas de los metales puros: resistencia a la tracción, velocidad de fluencia y tiempo de rotura bajo condiciones de fluencia. Para esas investigaciones se utilizó una máquina universal de ensayos para realizar los ensayos de tracción. La micro- estructura fue investigada por microscopía óptica. Basándose en los resultados obtenidos, se puede concluir que el platino, en comparación con el paladio, presenta mejores prestaciones para aplicaciones a alta temperatura.

  11. Biosorption of platinum and palladium for their separation/preconcentration prior to graphite furnace atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska-Zylkiewicz, Beata E-mail: bgodlew@uwb.edu.pl

    2003-08-15

    Inexpensive baker's yeast Saccharomyces cerevisiae and green algae Chlorella vulgaris, either free or immobilized on silica gel have been shown to selectively accumulate platinum and palladium from water samples in acidic medium (pH 1.6-1.8). Optimization of conditions of metals biosorption (sample pH, algae and yeast masses, adsorption time, temperature) was performed in batch mode. The procedure of matrix separation based on biosorption of platinum and palladium on algae C. vulgaris covalently immobilized on silica gel in flow mode was developed. The use of algae in flow procedure offers several advantages compared with its use in the batch mode. The procedure shows better reproducibility (<2%), improved efficiency of platinum retention on the column (93.3{+-}1.6%), is less laborious and less time consuming. The best recovery of biosorbed metals from column (87.7{+-}3.3% for platinum and 96.8{+-}1.1 for palladium) was obtained with solution of 0.3 mol l{sup -1} thiourea in 1 mol l{sup -1} hydrochloric acid. The influence of thiourea on analytical signals of examined metals during GFAAS determination is discussed. The procedure has been applied for separation of noble metals from tap and waste water samples spiked with platinum and palladium.

  12. Thermal stability of platinum, palladium and silver films on yttrium-stabilised zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Gesa, E-mail: gesa.beck@physik.uni-augsburg.de [Chair of Resource Strategy, Institute of Physics, University Augsburg, Universitaetsstrasse 1a, 86159 Augsburg (Germany); Bachmann, Christoph [Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen (Germany); Bretzler, Rita [Research Institute Precious Metals and Metals Chemistry, Katharinenstrasse 17, 73525 Schwaebisch Gmuend (Germany); Kmeth, Ralf [Chair of Resource Strategy, Institute of Physics, University Augsburg, Universitaetsstrasse 1a, 86159 Augsburg (Germany)

    2014-12-31

    Platinum, palladium and silver films with different microstructures have been prepared on differently orientated yttrium-stabilised zirconia (YSZ) substrates by pulsed laser deposition and then annealed at temperatures between 200 °C and 850 °C. Thereby, an influence of the type of metal, of the microstructure of the as-prepared film and of the orientation of the substrate on the annealing behaviour could be determined. The following annealing effects were observed for platinum, palladium and silver films: i) sharpening of the film boundary, ii) smoothing of the film surfaces, iii) sharpening of the texture [thereby: reduction of the fraction of small angle and twin grain boundaries], iv) grain growth and accordingly reduction of the fraction of grains as well as v) grooving at grain boundaries, vi) void formation at the metal|YSZ-interface, vii) hole formation within the films and viii) reduction of the fraction of droplets. In the case of palladium films also ix) oxidation [between 300 °C ≤ T < 750 °C] and stronger de-wetting phenomena than for platinum [with x) waving of the film and xi) island formation at T ≥ 750 °C] have been found. Silver films are not oxidised, but show stronger de-wetting phenomena than platinum and palladium, with xi) island formation and xii) evaporation of the silver at T ≥ 550 °C. Interestingly, silver films on (111) orientated YSZ are thermally much more stable than silver films on the other orientated substrates up to 750 °C. The annealing effects were described by interface, grain boundary and surface energy minimization. - Highlights: • The thermal stability of Pt, Pd and Ag films has been investigated up to 850 °C. • Annealing effects are e.g. reduction of the fraction of twins and island formation. • Pd is also oxidised between 300 °C ≤ T < 750 °C. • Annealing effects depend on type of metal and on its initial microstructure. • Annealing effects depend also on the orientation of substrate.

  13. Air-stable platinum and palladium complexes featuring bis[2,4-bis(trifluoromethyl)phenyl]phosphinous acid ligands.

    Science.gov (United States)

    Kurscheid, Boris; Neumann, Beate; Stammler, Hans-Georg; Hoge, Berthold

    2011-12-23

    Secondary phosphane oxides, R(2)P(O)H, are commonly used as preligands for transition-metal complexes of phosphinous acids, R(2)P-OH (R=alkyl, aryl), which are relevant as efficient catalysts in cross-coupling processes. In contrast to previous work by other groups, we are interested in the ligating properties of an electron-deficient phosphinous acid, (R(f))(2)P-OH, bearing the strongly electron-withdrawing and sterically demanding 2,4-bis(trifluoromethyl)phenyl group towards catalysis-relevant metals, such as palladium and platinum. The preligand bis[2,4-bis(trifluoromethyl)phenyl]phosphane oxide, (R(f))(2)P(O)H, reacts smoothly with solid platinum(II) dichloride yielding the trans-configured phosphinous acid platinum complex trans-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)]. The deprotonation of one phosphinous acid ligand with an appropriate base leads to the cis-configured monoanion complex cis-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H](-), featuring the quasi-chelating phosphinous acid phosphinito unit, (R(f))(2)P-O-H···O=P(R(f))(2), which exhibits a strong hydrogen bridge substantiated by an O···O distance of 245.1(4) pm. The second deprotonation step is accompanied by a rearrangement to afford the trans-configured dianion trans-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)](2-). The reaction of (R(f))(2)P(O)H with solid palladium(II) dichloride initially yields a mononuclear palladium complex [PdCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)], which condenses under liberation of HCl to the neutral dinuclear palladium complex [Pd(2)(μ-Cl)(2){({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H}(2)]. The equilibrium between the mononuclear [PdCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)] and dinuclear [Pd(2)(μ-Cl)(2){({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H}(2)] palladium complexes is reversible and can be shifted in each direction by the addition of base or HCl, respectively. Treatment of palladium(II) hexafluoroacetylacetonate, [Pd(F(6)acac)(2)], with a slight excess of (R(f))(2)P

  14. Palladium and platinum nanoparticles attenuate aging-like skin atrophy via antioxidant activity in mice.

    Science.gov (United States)

    Shibuya, Shuichi; Ozawa, Yusuke; Watanabe, Kenji; Izuo, Naotaka; Toda, Toshihiko; Yokote, Koutaro; Shimizu, Takahiko

    2014-01-01

    Cu-Zn superoxide dismutase (Sod1) loss causes a redox imbalance as it leads to excess superoxide generation, which results in the appearance of various aging-related phenotypes, including skin atrophy. Noble metal nanoparticles, such as palladium (Pd) and platinum (Pt) nanoparticles, are considered to function as antioxidants due to their strong catalytic activity. In Japan, a mixture of Pd and Pt nanoparticles called PAPLAL has been used to treat chronic diseases over the past 60 years. In the present study, we investigated the protective effects of PAPLAL against aging-related skin pathologies in mice. Transdermal PAPLAL treatment reversed skin thinning associated with increased lipid peroxidation in Sod1-/- mice. Furthermore, PAPLAL normalized the gene expression levels of Col1a1, Mmp2, Has2, Tnf-α, Il-6, and p53 in the skin of the Sod1-/- mice. Pt nanoparticles exhibited marked SOD and catalase activity, while Pd nanoparticles only displayed weak SOD and catalase activity in vitro. Although the SOD and catalase activity of the Pt nanoparticles significantly declined after they had been oxidized in air, a mixture of Pd and Pt nanoparticles continued to exhibit SOD and catalase activity after oxidation. Importantly, a mixture of Pd and Pt nanoparticles with a molar ratio of 3 or 4 to 1 continued to exhibit SOD and catalase activity after oxidation, indicating that Pd nanoparticles prevent the oxidative deterioration of Pt nanoparticles. These findings indicate that PAPLAL stably suppresses intrinsic superoxide generation both in vivo and in vitro via SOD and catalase activity. PAPLAL is a potentially powerful tool for the treatment of aging-related skin diseases caused by oxidative damage.

  15. Palladium and platinum nanoparticles attenuate aging-like skin atrophy via antioxidant activity in mice.

    Directory of Open Access Journals (Sweden)

    Shuichi Shibuya

    Full Text Available Cu-Zn superoxide dismutase (Sod1 loss causes a redox imbalance as it leads to excess superoxide generation, which results in the appearance of various aging-related phenotypes, including skin atrophy. Noble metal nanoparticles, such as palladium (Pd and platinum (Pt nanoparticles, are considered to function as antioxidants due to their strong catalytic activity. In Japan, a mixture of Pd and Pt nanoparticles called PAPLAL has been used to treat chronic diseases over the past 60 years. In the present study, we investigated the protective effects of PAPLAL against aging-related skin pathologies in mice. Transdermal PAPLAL treatment reversed skin thinning associated with increased lipid peroxidation in Sod1-/- mice. Furthermore, PAPLAL normalized the gene expression levels of Col1a1, Mmp2, Has2, Tnf-α, Il-6, and p53 in the skin of the Sod1-/- mice. Pt nanoparticles exhibited marked SOD and catalase activity, while Pd nanoparticles only displayed weak SOD and catalase activity in vitro. Although the SOD and catalase activity of the Pt nanoparticles significantly declined after they had been oxidized in air, a mixture of Pd and Pt nanoparticles continued to exhibit SOD and catalase activity after oxidation. Importantly, a mixture of Pd and Pt nanoparticles with a molar ratio of 3 or 4 to 1 continued to exhibit SOD and catalase activity after oxidation, indicating that Pd nanoparticles prevent the oxidative deterioration of Pt nanoparticles. These findings indicate that PAPLAL stably suppresses intrinsic superoxide generation both in vivo and in vitro via SOD and catalase activity. PAPLAL is a potentially powerful tool for the treatment of aging-related skin diseases caused by oxidative damage.

  16. Bioaccessibility of palladium and platinum in urban aerosol particulates

    Science.gov (United States)

    Puls, Christoph; Limbeck, Andreas; Hann, Stephan

    2012-08-01

    To evaluate potential health hazards caused by environmental Platinum Group Elements (PGEs), bioaccessibility of the metals in question needs to be assessed. To gain appropriate data, airborne particulate matter samples of different size fractions (total suspended particles as well as PM10 and PM2.5) were taken in downtown Vienna, an urban site primarily polluted by traffic. Total PGE concentrations in these samples were in the low picogram per cubic meter range, as determined by ID-ICP-MS after microwave digestion. For elimination of elements interfering with the accurate quantification, the digested samples were subjected to a cleaning procedure involving cation exchange. For determination of the bioaccessible fraction, it was assumed that inhaled particles are removed from the respiratory system by mucociliary clearance and subsequently ingested. Accordingly, the solubility of PGE in synthetic gastric juice was investigated by batch extraction of particulate matter samples followed by microwave assisted UV-digestion, cation exchange cleanup and ID-ICP-MS. The acquired data was used to calculate the bioaccessible fraction of Pd and Pt in airborne particulate matter. Average GIT-extractable fractions for Pd and Pt in TSP were 41% and 27%, in PM10 34% and 26%, respectively, thus exceeding previously determined values for bioaccessibility of PGE from ground catalyst materials by up to an order of magnitude.

  17. Palladium(Ⅱ) and Platinum(Ⅱ) Compounds Derived From Potentially Terdentate Ligands

    Institute of Scientific and Technical Information of China (English)

    C. López

    2005-01-01

    @@ 1Introduction Transition metalcomplexes derived from potentially terdentate ligands have attracted great interest in the late years. Among all the examples described so far, those containing palladium(Ⅱ) or platinum(Ⅱ) and ligands holding three heteroatoms with different donor abilities are particularly relevant. In compounds of this kind, the potential hemilability[1] of one of the terminal σ(M-donor atom) bonds, plays an important role in the view of their applications in homogeneous catalysis[2]. On the other hand, it is well-known that in dimetallic complexes the presence of two different metals in a close vicinity may influence their mutual cooperation in a wide variety of processes[3]. Besides that, some examples of the utility of chiral palladium( Ⅱ ) as well as platinum( Ⅱ ) complexes as precursors for organic and/or organometallic synthesis, as chiral recognitors or discriminators, or even in Bio-Medicine have also been reported[4- 6]. However, chiral heterodimetallic compounds holding ferrocenyl units and potentially terdentate ligands are scarce.

  18. Platinum and palladium doped tin oxide thick film sensors for sensing methane and hydrogen

    Science.gov (United States)

    Choudhary, Meenakshi; Mishra, V. N.; Dwivedi, R.

    2013-01-01

    In this work, platinum (Pt) and palladium (Pd) doped SnO2 thick film sensors have been developed using solid state derived tin oxide powder. Thick film sensors were fabricated on a 1˝x1˝ alumina substrate. The crystal structure and particle size are confirmed by X-ray diffraction (XRD) pattern. The fabricated sensors are tested for varying concentration (1-5%) of hydrogen and methane gas at different operating temperatures (200-350 °C). The effect of Pt and Pd doping have been analysed on different operating temperature, sensitivity and response/recovery time. The doping effects are also very important from view point of the gas selectivity. Based on the experimental results, we have observed the formation of tetragonal structure and particle size of the powders is drastically decreases from 26 to 19 nm after replacing the platinum dopant with palladium. Both the doped sensors have been found to be sensitive for hydrogen as compare to methane however, Pd-doped SnO2 sensor are most selective for hydrogen with very fast response and recovery time (20 s, 101 s) due to the small size effect.

  19. Reactivity studies of pincer bis-protic N-heterocyclic carbene complexes of platinum and palladium under basic conditions

    Science.gov (United States)

    Marelius, David C; Moore, Curtis E; Rheingold, Arnold L

    2016-01-01

    Summary Bis-protic N-heterocyclic carbene complexes of platinum and palladium (4) yield dimeric structures 6 when treated with sodium tert-butoxide in CH2Cl2. The use of a more polar solvent (THF) and a strong base (LiN(iPr)2) gave the lithium chloride adducts monobasic complex 7 or analogous dibasic complex 8. PMID:27559382

  20. Reactivity studies of pincer bis-protic N-heterocyclic carbene complexes of platinum and palladium under basic conditions

    Directory of Open Access Journals (Sweden)

    David C. Marelius

    2016-06-01

    Full Text Available Bis-protic N-heterocyclic carbene complexes of platinum and palladium (4 yield dimeric structures 6 when treated with sodium tert-butoxide in CH2Cl2. The use of a more polar solvent (THF and a strong base (LiN(iPr2 gave the lithium chloride adducts monobasic complex 7 or analogous dibasic complex 8.

  1. 从二次金粉中提取金、碲、铂、钯、硒工艺研究%Research on Extraction of Gold, Tellurium, Platinum, Palladium and Selenium From Platinum and Palladium Concentrate

    Institute of Scientific and Technical Information of China (English)

    赵祝鹏; 王兴; 崔家友; 张善辉; 侯绍彬; 王子旺

    2016-01-01

    In connection with the platinum and palladium concentrates produced in the course of processing the copper anode slime, utilizing the process of platinum and palladium concentrate pretreated by hydrochloric acid, tellurium subsided by sodium sulfite, acid-leaching slag dissolved by sodium chlorite, gold restored by oxalate, platinum and palladium subsided by ammonium chloride and selenium restored by SO2. The recovery rate of platinum and palladium is over 98%, the recovery of tellurium is over 95%, and the recovery of selenium is over 97%. The process has the advantage of selective separation from gold, tellurium, platinum, palladium and selenium, simple operation and high precious metals recovery.%针对在处理铜阳极泥过程中产生的二次金粉,采用盐酸对二次金粉进行预处理,亚硫酸钠沉碲;使用氯酸钠溶解酸浸渣,草酸还原金工艺,氯化铵沉铂钯,二氧化硫还原硒工艺,碲回收率达到95%以上,铂、钯回收率均在98%以上,硒回收率在97%以上,该工艺可选择性分离金、碲、铂、钯、硒,具有操作简单、贵金属回收率高等优点。

  2. Heterolytic activation of dihydrogen by platinum and palladium complexes

    NARCIS (Netherlands)

    Almeida Leñero, K.Q.; Guari, Y.; Kramer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L.

    2013-01-01

    Wide bite angle diphosphine ligands were used to prepare [(diphosphine)M(2-(diphenylphosphino)pyridine)]2+ complexes (M = Pd, Pt). Except for the ligand with the largest bite angle, 2-(diphenylphosphino)pyridine coordinates in a bidentate mode leading to bis-chelate complexes. In the case of Xantpho

  3. Heterolytic activation of dihydrogen by platinum and palladium complexes

    NARCIS (Netherlands)

    Lenero, K.Q.A.; Guari, Y.; Kamer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L.

    2013-01-01

    Wide bite angle diphosphine ligands were used to prepare [(diphosphine)M(2-(diphenylphosphino)pyridine)] (2+) complexes (M = Pd, Pt). Except for the ligand with the largest bite angle, 2-(diphenylphosphino) pyridine coordinates in a bidentate mode leading to bis-chelate complexes. In the case of Xan

  4. Heterolytic activation of dihydrogen by platinum and palladium complexes

    NARCIS (Netherlands)

    Almeida Leñero, K.Q.; Guari, Y.; Kramer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L.

    2013-01-01

    Wide bite angle diphosphine ligands were used to prepare [(diphosphine)M(2-(diphenylphosphino)pyridine)]2+ complexes (M = Pd, Pt). Except for the ligand with the largest bite angle, 2-(diphenylphosphino)pyridine coordinates in a bidentate mode leading to bis-chelate complexes. In the case of

  5. Heterolytic activation of dihydrogen by platinum and palladium complexes

    NARCIS (Netherlands)

    Almeida Leñero, K.Q.; Guari, Y.; Kramer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L.

    2013-01-01

    Wide bite angle diphosphine ligands were used to prepare [(diphosphine)M(2-(diphenylphosphino)pyridine)]2+ complexes (M = Pd, Pt). Except for the ligand with the largest bite angle, 2-(diphenylphosphino)pyridine coordinates in a bidentate mode leading to bis-chelate complexes. In the case of Xantpho

  6. Adsorption of volatile polonium species on metals in various gas atmospheres. Pt. II. Adsorption of volatile polonium on platinum, silver and palladium

    Energy Technology Data Exchange (ETDEWEB)

    Maugeri, Emilio Andrea; Joerg Neuhausen; Dressler, Rugard; Piguet, David; Voegele, Alexander; Schumann, Dorothea [Paul Scherrer Institut (PSI), Villigen (Switzerland). Lab. for Radiochemistry; Misiak, Ryszard [The Henryk Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Eichler, Robert [Paul Scherrer Institut (PSI), Villigen (Switzerland). Lab. for Radiochemistry; Bern Univ. (Switzerland). Dept. for Chemistry and Biochemistry

    2016-07-01

    This work presents the results obtained from studying the interaction between polonium compounds formed in different atmospheres and platinum, palladium and silver surfaces obtained by thermochromatography. These results are of crucial importance for the design of cover gas filter systems for lead-bismuth eutectic (LBE)-based nuclear facilities such as accelerator driven systems (ADS). The results obtained from studying the interaction of polonium and platinum under inert atmosphere and reducing atmospheres with and without addition of moisture show that polonium is deposited at temperatures between 993 and 1221 K, with adsorption enthalpies ranging from -235 to -291 kJ mol{sup -1}, indicating a very strong adsorption of the polonium species present on platinum surfaces. The interaction between polonium and silver was investigated using purified inert, reducing and oxidizing carrier gases. Results show a deposition temperature between 867 and 990 K, with adsorption enthalpies ranging from -205 to -234 kJ mol{sup -1}. The interaction of polonium and palladium was studied in purified helium and purified hydrogen. For both conditions a deposition temperature of 1221 K was observed corresponding to an adsorption enthalpy of -340 kJ mol{sup -1}. No highly volatile polonium species was formed at any of the applied experimental conditions.

  7. Simultaneous nondestructive analysis of palladium, rhodium, platinum, and gold nanoparticles using energy dispersive X-ray fluorescence.

    Science.gov (United States)

    Fiedler, Haidi D; Drinkel, Emma E; Orzechovicz, Beatriz; Leopoldino, Elder C; Souza, Franciane D; Almerindo, Gizelle I; Perdona, Cristian; Nome, Faruk

    2013-11-01

    A selective method is proposed for the determination of palladium, gold, and sulfur in catalytic systems, by direct liquid analysis using energy dispersive X-ray fluorescence (EDXRF), under an atmosphere of helium or air. This method allows a nondestructive analysis of palladium, rhodium, platinum, and gold nanoparticulate catalysts stabilized by imidazolium propane sulfonate based zwitterionic surfactants, allowing the samples to be reused for catalytic studies. The signals from palladium, rhodium, platinum, and gold samples in the presence of imidazolium propane sulfonate-based zwitterionic surfactants obtained using EDXRF before (Pd(2+), Rh(2+), Pt(2+), and Au(3+)) and after (Pd(0), Rh(0), Pt(0), and Au(0)) formation of nanoparticles are essentially identical. The results show that the EDXRF method is nondestructive and allows detection and quantification of the main components of platinum, gold, rhodium, and palladium NPs, including the surfactant concentration, with detection and quantification limits in the range of 0.4-3 mg L(-1). The matrices used in such samples present no problems, even allowing the detection and quantification of interfering elements.

  8. Separation of gold, palladium and platinum in chromite by anion exchange chromatography for inductively coupled plasma atomic emission spectrometric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kwang Soon; Lee, Chang Heon; Park, Yeong Jae; Joe, Kih Soo; Kim, Won Ho [KAERI, Taejon (Korea, Republic of)

    2001-08-01

    A study has been carried out on the separation of gold, iridium, palladium, rhodium, ruthenium and platinum in chromite samples and their quantitative determination using inductively coupled plasma atomic emission spectrometry (ICP-AES). The dissolution condition of the minerals by fusion with sodium peroxide was optimized and chromatographic elution behavior of the rare metals was investigated by anion exchange chromatography. Spectral interference of chromium, a matrix of the minerals, was investigated on determination of gold. Chromium interfered on determination of gold at the concentration of 500 mg/L and higher. Gold plus trace amounts of iridium, palladium, rhodium and ruthenium, which must be preconcentrated before ICP-AES was separated by anion exchange chromatography after reducing Cr(VI) to Cr(III) by H{sub 2}O{sub 2}. AuCl{sup -}{sub 4} retained on the resin column was selectively eluted with acetone- HNO{sub 3}-H{sub 2}O as an eluent. In addition, iridium, palladium, rhodium and ruthenium remaining on the resin column were eluted as a group with concentrated HCl. However, platinum was eluted with concentrated HNO{sub 3}. The recovery yield of gold with acetone-HNO{sub 3}-H{sub 2}O was 100.7 {+-} 2.0 % , and the yields of palladium and platinum with concentrated HCl and HNO{sub 3} were 96.1 {+-} 1.8% and 96.6 {+-} 1.3%, respectively. The contents of gold and platinum in a Mongolian chromite sample were 32.6 {+-} 2.2 {mu}g/g and 1.6 {+-} 0.14 {mu}g/g, respectively. Palladium was not detected.

  9. Structural, mechanical and magneto-electronic properties of the ternary sodium palladium and platinum oxides

    Energy Technology Data Exchange (ETDEWEB)

    Sadiq, Saima [Malakand Univ., Chakdara Dir (Pakistan). Center for Computational Materials Science; Malakand Univ., Chakdara Dir (Pakistan). Dept. of Chemistry; Ali, Zahid; Ahmad, Iftikhar; Khan, Imad; Rehman, Gul [Malakand Univ., Chakdara Dir (Pakistan). Center for Computational Materials Science; Malakand Univ., Chakdara Dir (Pakistan). Dept. of Physics; Sadiq, Muhammad; Rehman, Najeeb Ur [Malakand Univ., Chakdara Dir (Pakistan). Dept. of Chemistry

    2015-07-01

    Ternary palladium and platinum oxides NaPd{sub 3}O{sub 4} and NaPt{sub 3}O{sub 4} are studied theoretically using DFT. The calculated structural parameters and geometry are found consistent with the experiments. The mechanical properties analysis show that both compounds are elastically stable; anisotropic and reveal the ductile nature. Electronic cloud explain that the chemical bond between Na and Pd/Pt is ionic, whereas between O and Pd/Pt is covalent. The electronic band structures and densities of states demonstrate that these compounds are metals. The d-state splitting explains the origin of the electronic behaviour of these oxides. The optimised magnetic phase energies and magnetic susceptibility confirm that these oxides are paramagnetic metals.

  10. Synthesis of platinum and palladium complexes with bis-(hydroxy imines

    Directory of Open Access Journals (Sweden)

    Lucas M. Arantes

    2012-06-01

    Full Text Available The Schiff bases are an important class of compounds well used as ligands in coordination chemistry. The functionalized bis-imines, that represent a specific group of Schiff base, have been studied in our research group both for the evaluation of biological activity, against fungi and cancer, as for organocatalyst. Here the bis-imines 1 and 4 were synthesized in good yields by condensation of hydroxylated benzaldehydes with phenylenediamines. After that they were matched with Platinum and palladium salts providing three metallic complex (2, 3 and 5 that were fully characterized by nuclear magnetic resonance and mass spectrometry with electrospray ionization. Now these complexes are being tested in cross-coupling reactions of Heck and Suzuki.

  11. Study of Interaction Platinum Salts (Ii and Palladium (Ii on the Biologically Active Ligand

    Directory of Open Access Journals (Sweden)

    Asmat Nizami Kyzy Azizova

    2014-09-01

    Full Text Available Studied complexing ability of platinum (II and palladium (II with a time of personal gray-oxygen and sulfur-containing ligands donor nitrogens in different taniyah. A combination of functional groups. It is found that the complexation unimportant role nature of the starting metal salts, the pH of the medium, the nature of the solvent and the ratio of reactants. Determine the actual denticity tiodiuksusnoy, tiodipro propionic acid, mercaptoethanol, and bis -- hydroxyethyl sulfide. Discovered that a molecule entering the reaction of cysteamine origin walks splitting S–S communication and the resulting deproto-bined mercamine enter into complexation. In non-aqueous medium splitting S–S communication occurs.

  12. Application of cellulose anion-exchangers to separation of palladium from platinum or iridium with glycine as complexing agent and atomic-absorption spectrometry for detection.

    Science.gov (United States)

    Brajter, K; Słonawska, K

    1983-07-01

    The use of glycine as complexing agent for chromatographie separation of palladium from platinum, or palladium from iridium, on cellulose anion-exchangers has been investigated and found possible over a wide range of concentration ratios. The method can be used for analysis of Pd-Ir alloys. The nature of the complexes taking part in the ion-exchange has been identified.

  13. Novel platinum-palladium bimetallic nanoparticles synthesized by Dioscorea bulbifera: anticancer and antioxidant activities.

    Science.gov (United States)

    Ghosh, Sougata; Nitnavare, Rahul; Dewle, Ankush; Tomar, Geetanjali B; Chippalkatti, Rohan; More, Piyush; Kitture, Rohini; Kale, Sangeeta; Bellare, Jayesh; Chopade, Balu A

    2015-01-01

    Medicinal plants serve as rich sources of diverse bioactive phytochemicals that might even take part in bioreduction and stabilization of phytogenic nanoparticles with immense therapeutic properties. Herein, we report for the first time the rapid efficient synthesis of novel platinum-palladium bimetallic nanoparticles (Pt-PdNPs) along with individual platinum (PtNPs) and palladium (PdNPs) nanoparticles using a medicinal plant, Dioscorea bulbifera tuber extract (DBTE). High-resolution transmission electron microscopy revealed monodispersed PtNPs of size 2-5 nm, while PdNPs and Pt-PdNPs between 10 and 25 nm. Energy dispersive spectroscopy analysis confirmed 30.88% ± 1.73% elemental Pt and 68.96% ± 1.48% elemental Pd in the bimetallic nanoparticles. Fourier transform infrared spectra indicated strong peaks at 3,373 cm(-1), attributed to hydroxyl group of polyphenolic compounds in DBTE that might play a key role in bioreduction in addition to the sharp peaks at 2,937, 1,647, 1,518, and 1,024 cm(-1), associated with C-H stretching, N-H bending in primary amines, N-O stretching in nitro group, and C-C stretch, respectively. Anticancer activity against HeLa cells showed that Pt-PdNPs exhibited more pronounced cell death of 74.25% compared to individual PtNPs (12.6%) or PdNPs (33.15%). Further, Pt-PdNPs showed an enhanced scavenging activity against 2,2-diphenyl-1-picrylhydrazyl, superoxide, nitric oxide, and hydroxyl radicals.

  14. Structures of polynuclear complexes of palladium(II) and platinum(II) formed by slow hydrolysis in acidic aqueous solution.

    Science.gov (United States)

    Torapava, Natallia; Elding, Lars I; Mändar, Hugo; Roosalu, Kaspar; Persson, Ingmar

    2013-06-07

    The aqua ions of palladium(II) and platinum(II) undergo extremely slow hydrolysis in strongly acidic aqueous solution, resulting in polynuclear complexes. The size and structures of these species have been determined by EXAFS and small angle X-ray scattering, SAXS. For palladium(II), the EXAFS data show that the Pd-O and Pd···Pd distances are identical to those of crystalline palladium(II) oxide, but the intensities of the Pd···Pd distances in the Fourier transform at 3.04 and 3.42 Å are significantly lower compared to those of crystalline PdO. Furthermore, no Pd···Pd distances beyond 4 Å are observed. These observations strongly indicate that the polynuclear palladium(II) complexes are oxido- and hydroxido-bridged species with the same core structure as solid palladium(II) oxide. Based on the number of Pd···Pd distances, as derived from the EXAFS data, their size can be estimated to be approximately two unit cells, or ca. 1.0 nm(3). For platinum(II), EXAFS data of the polynuclear species formed in the slow hydrolysis process show Pt-O and Pt···Pt distances identical to those of amorphous platinum(II) oxide, precipitating from the solution studied. The Pt···Pt distances are somewhat different from those reported for crystalline platinum(II) oxide. The polynuclear platinum(II) complexes have a similar structure to the palladium ones, but they are somewhat larger, with an estimated diameter of 1.5-3.0 nm. It has not been possible to precipitate any of these species by ultracentrifugation. They are detectable by SAXS, indicating diameters between 0.7 and 2 nm, in excellent agreement with the EXAFS observations. The number of oxido- relative to hydroxido bridges will increase with increasing size of the complex. The charge of the complexes will remain about the same, +4, at growth, with approximate formulas [Pd10O4(OH)8(H2O)12](4+) and [Pt14O8(OH)8(H2O)12](4+) for complexes with a size of 2 and 3 unit cells of the corresponding solid metal oxide

  15. Antitumor activity of phenylene bridged binuclear bis(imino-quinolyl)palladium(II) and platinum(II) complexes.

    Science.gov (United States)

    Motswainyana, William M; Onani, Martin O; Madiehe, Abram M; Saibu, Morounke

    2014-04-01

    Antitumor effects of a known bis(imino-quinolyl)palladium(II) complex 1 and its newly synthesized platinum(II) analogue 2 were evaluated against human breast (MCF-7) and human colon (HT-29) cancer cell lines. The complexes gave cytotoxicity profiles that were better than the reference drug cisplatin. The highest cytotoxic activities were pronounced in complex 2 across the two examined cancer cell lines. Both compounds represent potential active drugs based on bimetallic complexes.

  16. Catalytic wet oxidation of ammonia solution: activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst.

    Science.gov (United States)

    Hung, Chang-Mao

    2009-04-15

    Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H(2)PtCl(6), Pd(NO(3))(3) and Rh(NO(3))(3). Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes.

  17. Palladium, platinum, and rhodium contents of rocks near the lower margin of the Stillwater complex, Montana.

    Science.gov (United States)

    Zientek, M.L.; Foose, M.P.; Leung, Mei

    1986-01-01

    Statistical summaries are reported for Pd, Pt and Rh contents of rocks from the lower part of the Stillwater complex, the underlying contact-metamorphosed sediments, and post-metamorphic dykes and sills wholly within the hornfelses. Variability of the data among the rock types is attributed largely to differences in sulphide content. Non-correlation of sulphur with platinum-group assays of many rock types leads to the suggestion that the immiscible sulphide and silicate liquids did not completely equilibrate with respect to platinum-group elements. -G.J.N.

  18. Biogenic platinum and palladium nanoparticles as new catalysts for the removal of pharmaceutical compounds.

    Science.gov (United States)

    Martins, Mónica; Mourato, Cláudia; Sanches, Sandra; Noronha, João Paulo; Crespo, M T Barreto; Pereira, Inês A C

    2017-01-01

    Pharmaceutical products (PhP) are one of the most alarming emergent pollutants in the environment. Therefore, it is of extreme importance to investigate efficient PhP removal processes. Biologic synthesis of platinum nanoparticles (Bio-Pt) has been reported, but their catalytic activity was never investigated. In this work, we explored the potential of cell-supported platinum (Bio-Pt) and palladium (Bio-Pd) nanoparticles synthesized with Desulfovibrio vulgaris as biocatalysts for removal of four PhP: ciprofloxacin, sulfamethoxazole, ibuprofen and 17β-estradiol. The catalytic activity of the biological nanoparticles was compared with the PhP removal efficiency of D. vulgaris whole-cells. In contrast with Bio-Pd, Bio-Pt has a high catalytic activity in PhP removal, with 94, 85 and 70% removal of 17β-estradiol, sulfamethoxazole and ciprofloxacin, respectively. In addition, the estrogenic activity of 17β-estradiol was strongly reduced after the reaction with Bio-Pt, showing that this biocatalyst produces less toxic effluents. Bio-Pt or Bio-Pd did not act on ibuprofen, but this could be completely removed by D. vulgaris whole-cells, demonstrating that sulfate-reducing bacteria are among the microorganisms capable of biotransformation of ibuprofen in anaerobic environments. This study demonstrates for the first time that Bio-Pt has a high catalytic activity, and is a promising catalyst to be used in water treatment processes for the removal of antibiotics and endocrine disrupting compounds, the most problematic PhP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Copper-, palladium-, and platinum-containing complexes of an asymmetric dinucleating ligand.

    Science.gov (United States)

    Halvagar, Mohammad Reza; Neisen, Benjamin; Tolman, William B

    2013-01-18

    The coordination chemistry of an asymmetric dinucleating hexadentate ligand LH(2) comprising neutral alkyltriamine and potentially dianionic dicarboxamido-pyridyl donor sets with copper, palladium, and platinum has been explored. Monometallic, dicopper, and heterodinuclear Cu-Pd and -Pt complexes have been prepared and characterized, including by NMR, EPR, UV-vis, and IR spectroscopy and X-ray crystallography. For example, the monometallic complexes [(LH(2))MCl]X (M = Cu, X = OTf; M = Pd or Pt, X = Cl) were prepared, wherein the metal(II) ions are coordinated to the triamine portion and the pyridyldicarboxamide is unperturbed. Treatment of LH(2) with [MesCu](x) (Mes = mesityl) provided a monocopper(I) complex, again with the metal coordinated only to the trialkylamine donor set. Reaction of [(LH(2))CuCl]OTf with NaOMe resulted in an unexpected migration of the copper(II)-chloride fragment to the pyridyldicarboxamide site to yield Na[LCuCl], from which a dicopper complex LCu(2)Cl(2) and mixed-metal complexes LCu(Cl)M(Cl) (M = Pd, Pt) were prepared by addition of CuCl(2) or MCl(2), respectively. The heterodinuclear complexes were also prepared by addition of CuCl(2) to [(LH(2))MCl]Cl.

  20. 16 CFR 23.7 - Misuse of the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium,” and “osmium.”

    Science.gov (United States)

    2010-01-01

    ... § 23.7 Misuse of the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium,” and “osmium.” (a) It is unfair or deceptive to use the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium... marking or description misrepresents the product's true composition. The Platinum Group Metals (PGM)...

  1. Reactivity indexes for different geometries of palladium leads

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Carrillo, S C; Bolcatto, P G [Departamento de Fisica, Facultad de Ingenieria Quimica, Universidad Nacional de Litoral, Santiago del Estero 2829 S3000AOM Santa Fe Argentina (Argentina); Ortega, J, E-mail: scgomez@fiq.unl.edu.a [Departamento de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid (Spain)

    2009-05-01

    Electronic transport through metallic break junctions or molecules is clearly dependent not only on the electronic structure of the central nanodevice connecting the leads, but also the shape and crystalline orientation of the contacts which can define the possible conduction channels. In this work we examine different geometries of contacts of palladium characterizing them through global and local reactivity indexes as electrophilicity, chemical hardness and Fukui functions. In molecules, these indicators are essentially defined by the energies of the frontier molecular orbitals and in solids they are related with the local and partial density of states. We use for this purpose an ab-initio based code (FIREBALL), applied to plane contacts with (001) fcc faces and also pyramidal tips grown following a (001) and (111) packaging. The results allow us to have an insight about the chemical features of this type of nanojunctions.

  2. Triphenyl phosphine adducts of platinum(IV) and palladium(II) dithiocarbamates complexes: a spectral and in vitro study

    Science.gov (United States)

    Manav, N.; Mishra, A. K.; Kaushik, N. K.

    2004-11-01

    Triphenyl phosphine adducts of dithiocarbamate complexes of platinum(IV) and palladium(II) of the type [Pt(L) 2PPh 3Cl 2] and [Pd(L) 2PPh 3] [L: morpholine dithiocarbamate (L 1), aniline dithiocarbamate (L 2) and N-(methyl, cyclohexyl) dithiocarbamate (L 3)] were prepared and characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectral studies. Thermal studies of the complexes were carried out. In vitro antitumor activity has been screened towards human adenocarcinoma cell lines and showed significant inhibition even at very low concentration.

  3. Palladium, Platinum and Gold Concentrations in Fengshan Porphyry Cu-Mo Deposit, Hubei Province, China

    Institute of Scientific and Technical Information of China (English)

    WANG Minfang; DENG Xiaodong; BI Shijian; LI Zhanke

    2009-01-01

    The Fengshan porphyry-skarn copper-molybdenum (Cu-Mo) deposit is located in the south-eastern Hubei Province in east China. Cu-Mo mineralization is hosted in the Fengshan granodiorite porphyry stock that intruded the Triassic Daye Formation carbonate rocks in the early Cretaceous (~140 Ma), as well as the contact zone between granodiorite porphyry stock and carbonate rocks, forming the porphyry-type and skarn-type association. The Fengshan granodiorite stock and the immediate country rocks are strongly fractured and intensely altered by hydrothermal fluids. In addition to intense skarn alteration, the prominent alteration types are potassic, phyllic, and propylitic, whereas argillation is less common. Mineralization occurs as veins, stock works, and disseminations, and the main ore minerals are chalcopyrite, pyrite, molybdenite, bornite, and magnetite. The contents of palladium, platinum and gold (Pd, Pt and Au) are determined in nine samples from fresh and mineralized granodiorite and different types of altered rocks. The results show that the Pd content is systematically higher than Pt, which is typical for porphyry ore deposits worldwide. The Pt content ranges from 0.037 tul.765 ppb, and the Pd content ranges between 0.165and 17.979 ppb. Pd and Pt are more concentrated in porphyry mineralization than skarn mineralization, and have negative correlations with Au. The reconnaissance study presented here confirms the existence of Pd and Pt in the Fengshan porphyry-skarn Cu-Mo deposit. When compared with intracontinent and island arc geotectonic settings, the Pd, Pt, and Au contents in the Fengshan porphyry Cu-Mo deposit in the intracontinent is lower than the continental margin types and island are types. A combination of available data indicates that Pd and Pt were derived from oxidized alkaline magmas generated by the partial melting of an enriched mantle source.

  4. Catalytically activated palladium@platinum nanowires for accelerated hydrogen gas detection.

    Science.gov (United States)

    Li, Xiaowei; Liu, Yu; Hemminger, John C; Penner, Reginald M

    2015-03-24

    Platinum (Pt)-modified palladium (Pd) nanowires (or Pd@Pt nanowires) are prepared with controlled Pt coverage. These Pd@Pt nanowires are used as resistive gas sensors for the detection of hydrogen gas in air, and the influence of the Pt surface layer is assessed. Pd nanowires with dimensions of 40 nm (h) × 100 nm (w) × 50 μm (l) are first prepared using lithographically patterned nanowire electrodeposition. A thin Pt surface layer is electrodeposited conformally onto a Pd nanowire at coverages, θPt, of 0.10 monolayer (ML), 1.0 ML, and 10 ML. X-ray photoelectron spectroscopy coupled with scanning electron microscopy and electrochemical measurements is consistent with a layer-by-layer deposition mode for Pt on the Pd nanowire surface. The resistance of a single Pd@Pt nanowire is measured during the exposure of these nanowires to pulses of hydrogen gas in air at concentrations ranging from 0.05 to 5.0 vol %. Both Pd nanowires and Pd@Pt nanowires show a prompt and reversible increase in resistance upon exposure to H2 in air, caused by the conversion of Pd to more resistive PdHx. Relative to a pure Pd nanowire, the addition of 1.0 ML of Pt to the Pd surface alters the H2 detection properties of Pd@Pt nanowires in two ways. First, the amplitude of the relative resistance change, ΔR/R0, measured at each H2 concentration is reduced at low temperatures (T = 294 and 303 K) and is unaffected at higher temperatures (T = 316, 344, and 376 K). Second, response and recovery rates are both faster at all temperatures in this range and for all H2 concentrations. For higher θPt = 10 ML, sensitivity to H2 is dramatically reduced. For lower θPt = 0.1 ML, no significant influence on sensitivity or the speed of response/recovery is observed.

  5. Platinum Inhibits Low-Temperature Dry Lean Methane Combustion through Palladium Reduction in Pd-Pt/Al2 O3 : An In Situ X-ray Absorption Study.

    Science.gov (United States)

    Nassiri, Hanieh; Lee, Kee-Eun; Hu, Yongfeng; Hayes, Robert E; Scott, Robert W J; Semagina, Natalia

    2017-01-18

    Palladium-platinum bimetallic catalysts supported on alumina with palladium/platinum molar ratios ranging from 0.25 to 4 are studied in dry lean methane combustion in the temperature range of 200 to 500 °C. Platinum addition decreases the catalyst activity, which cannot be explained by the decrease in dispersion or the structure sensitivity of the reaction. In situ X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopy measurements have been conducted for monometallic Pd, Pt, and 2:1 Pd-Pt catalysts. Monometallic palladium is fully oxidized in the full temperature range, whereas platinum addition promotes palladium reduction, even in a reactive oxidizing environment. The Pd/PdO weight ratio in bimetallic Pd-Pt 2:1 catalysts decreases from 98/2 to 10/90 in the 200-500 °C temperature range under the reaction conditions. Thus, platinum promotes the formation of the reduced palladium phase with a significantly lower activity than that of oxidized palladium. The study sheds light on the effect of platinum on the state of the active palladium surface under low-temperature dry lean methane combustion conditions, which is important for methane-emission control devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Effects of High-Humidity Aging on Platinum, Palladium, and Gold Loaded Tin Oxide—Volatile Organic Compound Sensors

    Directory of Open Access Journals (Sweden)

    Maiko Nishibori

    2010-07-01

    Full Text Available This study is an investigation of high-humidity aging effects on the total volatile organic compound (T–VOC gas-sensing properties of platinum, palladium, and gold-loaded tin oxide (Pt,Pd,Au/SnO2 thick films. The sensor responses of the high-humidity aged Pt,Pd,Au/SnO2, a non-aged Pt,Pd,Au/SnO2, and a high-humidity aged Pt/SnO2 to T–VOC test gas have been measured. The high-humidity aging is an effective treatment for resistance to humidity change for the Pt,Pd,Au/SnO2 but not effective for the Pt/SnO2. The mechanism of the high-humidity aging effects is discussed based on the change of surface state of the SnO2 particles.

  7. Theoretical studies on vibrational spectra of mixed cyanide-halide complexes of platinum(IV) and palladium(IV)

    Science.gov (United States)

    Zhang, Yu; Zhang, Lin; Tao, Hanbing; Sun, Xiaojuan; Zhu, Longgen

    2003-02-01

    The vibrational spectra of mixed cyanide-halide complexes, M(CN) 4X 22- and M(CN) 5X 2- (M=Pt and Pd; X=F, Cl, Br and I), have been systematically investigated by ab initio RHF, B3LYP and MP2 methods with LanL2DZ and SDD basis sets. The calculated vibrational frequencies of platinum complexes are evaluated via comparison with the experimental values. In the infrared frequency region, the CN stretching vibrational frequencies calculated at B3LYP level with two basis sets are in good agreement with the observed values with deviations, -16-4 cm -1 for Pt(CN) 4X 22- and -18 to -2 cm -1 for Pt(CN) 5X 2-. However, in far-infrared region, the results obtained at RHF level are better than those calculated at B3LYP and MP2 levels. For RHF/SDD method, the deviations for PtX and PtC stretching vibrational frequencies are -14-1 and -12 to -2 cm -1 in the complex Pt(CN) 4X 22-, -19 to -11 and -15-14 cm -1 in the Pt(CN) 5X 2- complex, respectively. The vibrational frequencies of palladium(IV) and some platinum(IV) complexes that have not been experimentally reported are predicted.

  8. Palladium under potential deposition on platinum monocrystals: study of the Pd-H system in low dimensionality; Depot en sous potentiel de palladium sur monocristaux de platine: etude du systeme Pd-H en basse dimensionnalite

    Energy Technology Data Exchange (ETDEWEB)

    Lebouin, Ch.; Soldo Olivier, Y.; Chatenet, M.; Faure, R. [Grenoble-1 Univ. Joseph-Fourier, Lab. d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, CNRS-INPG-UFJ, 38 (France); Lebouin, Ch.; Millet, P. [Paris-11 Univ., Institut de Chimie Moleculaire et des Materiaux d' Orsay, UMR 8182, 91 - Orsay (France)

    2006-07-01

    In this work is studied the Pd-H system in a low dimensionality. The study is characterized by a palladium deposition of a nano-metric thickness, carried out by an electrochemical way, in epitaxy on the dense face of a platinum monocrystal. The palladium layers are obtained by under potential deposition in presence of chloride ions. These depositions have been carried out in using two methods 1)the volt-amperometric scanning and 2)the chrono-potentiometry. The volt-amperometric study has revealed the importance of the chloride ions in the obtention of a deposition in under potential deposition. Optimal experimental conditions (required chloride concentration, scanning zone in potential and scanning velocity) have then been defined. With the aim to better control the deposition, depositions by chrono-potentiometry have been carried out too. The obtained experimental results are explained. By these two methods, palladium depositions of the layer fraction to some complete layers have been carried out; these depositions have been analyzed by an electrochemical way in sulfuric acid or perchloric acid solution, using the under potential deposition of the hydrogen as characterization probe. Typical answers of the hydrogen adsorption/desorption on Pd/Pt(111) have been observed at about 0.16 V/ENH for {theta}(palladium){<=}1 and at about 0.21 V/ENH on the depositions zones where {theta}(palladium){>=}1 in sulfuric medium. These experimental results are explained. (O.M.)

  9. Structural, spectroscopic and quantum chemical studies of acetyl hydrazone oxime and its palladium(II) and platinum(II) complexes

    Science.gov (United States)

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T.; Buyukgungor, Orhan

    2015-09-01

    Acetyl hydrazone oxime, [(1E,2E)-2-(hydroxyimino)-1-phenylethylidene]acetohydrazone (hipeahH2) and its palladium(II) and platinum(II) complexes, [M(hipeahH)2] (M = PdII and PtII), have been synthesized and characterized by elemental analysis, UV-vis IR, NMR and LC-MS techniques. X-ray diffraction analysis of [Pd(hipeahH)2] shows that the two hipeahH2 ligands are not equal; one of the ligands loses the hydrazone proton, while the other one loses the oxime proton, resulting in a different coordination behavior to form five- and six-membered chelate rings. The molecular geometries from X-ray experiments in the ground state were compared using the density functional theory (DFT) with the B3LYP method combined with the 6-311++G(d,p) basis set for the ligand and the LanL2DZ basis set for the complexes. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR, NMR and UV-vis spectrometry. In addition, the isomer studies of ligand and its complexes were made by DFT.

  10. Process for applying a catalytically active coating, particularly one containing platinum and/or palladium on catalyst carrier. Verfahren zum Aufbringen eines katalytisch aktiven, insbesondere Platin und/oder Palladium enthaltenden Ueberzugs auf Katalysatortraeger

    Energy Technology Data Exchange (ETDEWEB)

    Bozon, A.; Lakatos, E.; Koberstein, E.; Pletka, H.D.; Voelker, H.

    1981-09-03

    The invention concerns an improved process for applying a platinum and/or palladium, coating or films, possibly one containing other platinum group metals and/or nonprecious metals, by means of solutions of the metal compounds on the outer surface of porous catalyst carriers, i.e. those having a large surface. It was found that aquaeous solutions of ammonium chloride can be used to advantage to pre-charge the catalyst carrier, instead of the previously used organic solvents, where the saturation of the catalyst carrier must not be exceeded. After impregnation with an aquaeous solution of the catalytically active elements, the liquid is finally removed by heating. In the engine exhaust gas test, the catalysts according to the invention proved superior to the conventional ones.

  11. 降低AgCl沉淀对铂和钯吸附的研究%Research of reducing the AgCl precipitate on the adsorption of platinum and palladium

    Institute of Scientific and Technical Information of China (English)

    韩丽娟; 胡军凯; 吴一微

    2012-01-01

    研究用盐酸沉淀银时,加入EDTA络合剂,降低AgCl沉淀对铂和钯吸附,用电感耦合等离子体发射光谱法测定溶液中的铂和钯,其回收率均大于98%.%Silver was precipitated in hydrochloric acid media by adding chelating agent of EDTA to reduce AgCl precipitate on the adsorption of platinum and palladium.The contents of platinum and palladium in the solution were determined by ICP-AES with their recoveries over 98%.

  12. Synthesis and reactivity of Ph/sub 2/PCH/sub 2/PPh/sub 2/- (dppm-) stabilized Pd-Co and Pd-Pt-Co clusters. Effect of platinum versus palladium on the neighboring palladium center

    Energy Technology Data Exchange (ETDEWEB)

    Braunstein, P.; de Meric de Bellefon, C.; Ries, M.

    1988-04-20

    The quantitative and regioselective synthesis of the mixed-metal cluster (PdPtCo/sub 2/(CO)/sub 7/(dppm)/sub 2/) (1b) was achieved by the reaction of the bimetallic complex (PdPtCl/sub 2/(dppm)/sub 2/) (dppm = /mu/-Ph/sub 2/PCH/sub 2/PPh/sub 2/) with (Co(CO)/sub 4/)/sup /minus//. As a result of phosphorus migration from palladium to cobalt, formal insertion of the Co(CO)/sub 3/ fragment into a metal-phosphorus bond of the precursor exclusively occurs into the more labile P /yields/ Pd bond. The lability of the exocyclic Co(CO)/sub 4/ fragment was evidenced and compared between 1b and (Pd/sub 2/Co/sub 2/(CO)/sub 7/(dppm)/sub 2/) (1a). Although a Pd-Co bond is involved, this lability is very sensitive to the neighboring metal center (Pd or Pt). Transmission of electronic effects from one metal-center to another was evidenced, and a platinum effect was observed in dissociating solvents, where 1a is partly dissociated but 1b is completely dissociated into (PdPtCo(CO)/sub 3/(S)(dppm)/sub 2/)(CO(CO)/sub 4/) (S = solvent). This is a reversible process, as is the equilibrium between 1 and halide anions. Solvento clusters were prepared that possess a labile coordination site on Pd leading to completely regioselective reactions with donor molecules, e.g., phosphines, CO, or C/sub 2/Ph/sub 2/. These ligands are labile (PR/sub 3/ < CO < C/sub 2/Ph/sub 2/ < MeCN < THF), and reversible CO uptake and substitution experiments showed that the Pd-bound CO in 4b is less labile than in 4a, indicating again a platinum effect on the reactive Pd center. The tris(bis(diphenylphosphino)methane) cationic cluster (Pd/sub 2/Co(CO)/sub 2/(dppm)/sub 3/)/sup +/ was isolated, in which all the metal-metal bonds are bridged by dppm ligands. Spectroscopic IR and /sup 1/H, /sup 31/P(/sup 1/H), and /sup 195/Pt(/sup 1/H) NMR data are discussed and confirm that in these reactions the PdMCo(dppm)/sub 2/ (M = Pd, Pt) framework is maintained.

  13. A rapid fire-assay/atomic-absorption method for the determination of platinum, palladium and gold in ores and concentrates: A modification of the tin-collection scheme.

    Science.gov (United States)

    Moloughney, P E; Faye, G H

    1976-05-01

    The tin-collection scheme of fire-assaying has been simplified to permit the rapid and accurate determination of platinum, palladium and gold in ores and related materials. The presence of tellurium in the charge ensures that the precious metals remain insoluble during the parting of the tin button with hydrochloric acid. The residue is easily collected and dissolved and the resultant solution analysed for the precious metals by AAS. The accuracy of the method has been established by application to five diverse certified reference materials.

  14. Kinetics of benzene hydrogenation on supported platinum, palladium, rhodium and ruthenium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, K.; Fueda, Y.; Kusunoiki, K.; Uchino, T.

    1982-10-01

    Although benzene hydrogenation has been widely utilized as a test reaction for the investigation of catalytic activity, the reaction mechanism has not been well elucidated. As to the Langmuir-Hinshelwood rate equations, there have been many reports for the reaction on nickel catalysts, but few papers have been published on platinum metal catalysts, especially on rhodium and ruthenium catalysts. In this communication, reaction rates were measured for benzene hydrogenation over commercially available Pt-, Pd-, Rh- and Ru-Al/sub 2/O/sub 3/ catalysts and the rate equation was derived. The thermodynamic consistency of the rate equation was then tested in the light of the rules established by Boudart et al. and Vannice et al.

  15. PALLADIUM, PLATINUM, RHODIUM, RUTHENIUM AND IRIDIUM IN PERIDOTITES AND CHROMITITES FROM OPHIOLITE COMPLEXES IN NEWFOUNDLAND.

    Science.gov (United States)

    Page, Norman J; Talkington, Raymond W.

    1984-01-01

    Samples of spinel lherzolite, harzburgite, dunite, and chromitite from the Bay of Islands, Lewis Hills, Table Mountain, Advocate, North Arm Mountain, White Hills Periodite Point Rousse, Great Bend and Betts Cove ophiolite complexes in Newfoundland were analyzed for the platinum-group elements (PGE) Pd, Pt, Rh, Ru and Ir. The ranges of concentration (in ppb) observed for all rocks are: less than 0. 5 to 77 (Pd), less than 1 to 120 (Pt), less than 0. 5 to 20 (Rh), less than 100 to 250 (Ru) and less than 20 to 83 (Ir). Chondrite-normalized PGE ratios suggest differences between rock types and between complexes. Samples of chromitite and dunite show relative enrichment in Ru and Ir and relative depletion in Pt and Pd.

  16. Microwave assisted synthesis, characterization and biological evaluation of palladium and platinum complexes with azomethines

    Science.gov (United States)

    Sharma, Krishna; Singh, Ritu; Fahmi, Nighat; Singh, R. V.

    2010-01-01

    Reactions of 3-acetyl-2,5-dimethylthiophene with thiosemicarbazide and semicarbazide hydrochloride resulted in the formation of new heterocyclic ketimines, 3-acetyl-2,5-dimethylthiophene thiosemicarbazone (C 9H 13N 3OS 2 or L 1H) and 3-acetyl-2,5- dimethylthiophene semicarbazone (C 9H 13N 3OS or L 2H), respectively. The Pd(II) and Pt(II) complexes have been synthesized by mixing metal salts in 1:2 molar ratios with these ligands by using microwave as well as conventional heating method for comparison purposes. The authenticity of these ligands and their complexes has been established on the basis of elemental analysis, melting point determinations, molecular weight determinations, IR, 1H NMR and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a monobasic bidentate manner and square planar environment around the metal atoms has been proposed to the complexes. Both the ligands and their complexes have been screened for their antimicrobial activities. The antiamoebic activity of both the ligands and their palladium compounds against the protozoan parasite Entamoeba histolytica has been tested.

  17. Microwave assisted synthesis, characterization and biological evaluation of palladium and platinum complexes with azomethines.

    Science.gov (United States)

    Sharma, Krishna; Singh, Ritu; Fahmi, Nighat; Singh, R V

    2010-01-01

    Reactions of 3-acetyl-2,5-dimethylthiophene with thiosemicarbazide and semicarbazide hydrochloride resulted in the formation of new heterocyclic ketimines, 3-acetyl-2,5-dimethylthiophene thiosemicarbazone (C(9)H(13)N(3)OS(2) or L(1)H) and 3-acetyl-2,5- dimethylthiophene semicarbazone (C(9)H(13)N(3)OS or L(2)H), respectively. The Pd(II) and Pt(II) complexes have been synthesized by mixing metal salts in 1:2 molar ratios with these ligands by using microwave as well as conventional heating method for comparison purposes. The authenticity of these ligands and their complexes has been established on the basis of elemental analysis, melting point determinations, molecular weight determinations, IR, (1)H NMR and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a monobasic bidentate manner and square planar environment around the metal atoms has been proposed to the complexes. Both the ligands and their complexes have been screened for their antimicrobial activities. The antiamoebic activity of both the ligands and their palladium compounds against the protozoan parasite Entamoeba histolytica has been tested.

  18. Synthesis, characterization and modification of LiFePO4 by doping with platinum and palladium for lithium-ion batteries

    Science.gov (United States)

    Talebi-Esfandarani, Majid

    Lithium iron phosphate (LiFePO4) with features of excellent thermal stability, non-toxicity, low cost and abundance in nature is one of the most promising cathode materials to be used in lithium ion batteries. However, as it suffers from the low electrical conductivity and poor ionic diffusion, it operates only at low charge/discharge current rates. In this thesis, a dual approach of metal doping and carbon coating was employed to solve the aforementioned problem. This work is mainly on the study, for the first time, of the effect of platinum and palladium doping of LiFePO 4 on its physical-chemical properties. The effect of Pt and Pd doping on the LiFePO4 performance as Li-ion cathode will be also shown. Sol-gel and hydrothermal methods were used to synthesize the LiFePO4 and doped-LiFePO4 cathode materials. The prepared materials were characterized using different methods such as XRD (X-ray Diffraction), XPS (X-ray Photoelectron Spectroscopy), SEM (Scanning Electron Microscopy) and BET (Brunauer Emmett Teller). The electrochemical characterization techniques including charge/discharge test, CV (Cyclic Voltammetry), EIS (Electrochemical Impedance Spectroscopy) and cycling were also used. The effects of metals doping on chemical-physical properties, particles sizes, morphology, structure and purity of the electrodes were investigated and their correlation to the electrochemical properties of materials were studied. In the first section, we determine the optimized amount of carbon support and morphology of the particles using SEM which help to obtain LiFePO 4/C cathode material with an excellent electrochemical performance. It was found that when the amount of coated carbon exceeds the optimized value, the discharge capacity of the LiFePO4/C material decreased. This might indicate a low diffusion of the Li+ ions through the carbon layers during the charge/discharge process. On the other hand, for LiFePO4 coated with carbon quantity lower than the optimum value, Li

  19. MONTANA PALLADIUM RESEARCH INITIATIVE

    Energy Technology Data Exchange (ETDEWEB)

    Peters, John; McCloskey, Jay; Douglas, Trevor; Young, Mark; Snyder, Stuart; Gurney, Brian

    2012-05-09

    Project Objective: The overarching objective of the Montana Palladium Research Initiative is to perform scientific research on the properties and uses of palladium in the context of the U.S. Department of Energy's Hydrogen, Fuel Cells and Infrastructure Technologies Program. The purpose of the research will be to explore possible palladium as an alternative to platinum in hydrogen-economy applications. To achieve this objective, the Initiatives activities will focus on several cutting-edge research approaches across a range of disciplines, including metallurgy, biomimetics, instrumentation development, and systems analysis. Background: Platinum-group elements (PGEs) play significant roles in processing hydrogen, an element that shows high potential to address this need in the U.S. and the world for inexpensive, reliable, clean energy. Platinum, however, is a very expensive component of current and planned systems, so less-expensive alternatives that have similar physical properties are being sought. To this end, several tasks have been defined under the rubric of the Montana Palladium Research Iniative. This broad swath of activities will allow progress on several fronts. The membrane-related activities of Task 1 employs state-of-the-art and leading-edge technologies to develop new, ceramic-substrate metallic membranes for the production of high-purity hydrogen, and develop techniques for the production of thin, defect-free platinum group element catalytic membranes for energy production and pollution control. The biomimetic work in Task 2 explores the use of substrate-attached hydrogen-producing enzymes and the encapsulation of palladium in virion-based protein coats to determine their utility for distributed hydrogen production. Task 3 work involves developing laser-induced breakdown spectroscopy (LIBS) as a real-time, in situ diagnostic technique to characterize PGEs nanoparticles for process monitoring and control. The systems engineering work in task 4

  20. 金宝山铂钯矿矿石选矿研究%Beneficiability Study of the Ore in Jingbaoshan Platinum-palladium Deposit

    Institute of Scientific and Technical Information of China (English)

    宋焕斌

    2006-01-01

    根据矿石的工艺性质,对金宝山铂钯矿石进行了大量探索性试验和条件试验,对磨矿细度、药剂制度和选矿工艺流程进行了详细研究.试验表明,铂钯的回收率为74.73%,对于这类微细粒低品位矿石,这是一个理想的结果;铜的回收率86.07%;镍的回收率为54.92%.精矿中氧化镁的含量偏高,达20.56%.%In accordance with the ore's process property, massive exploratory experiments and condition tests on the platinum-palladium ore in Jinbaoshan, detailed researches have been carried out into the grinding fineness, reagent and technological flowsheet. According to our test, the recovery ratio of platinum-palladium is 74.73%, which is an ideal result for micro-grained and low grade ores. The recovery ratio of copper is 86.07%, The recovery ratio of nickel is 54.92%. The content of MgO in the concentrate is on the high side,as high as 20.56%.

  1. A rapid and practical strategy for the determination of platinum, palladium, ruthenium, rhodium, iridium and gold in large amounts of ultrabasic rock by inductively coupled plasma optical emission spectrometry combined with ultrasound extraction

    Science.gov (United States)

    Zhang, Gai; Tian, Min

    2015-04-01

    This proposed method regulated the determination of platinum, palladium, ruthenium, rhodium, iridium and gold in platinum-group ores by nickel sulfide fire assay—inductively coupled plasma optical emission spectrometry (ICP-OES) combined with ultrasound extraction for the first time. The quantitative limits were 0.013-0.023μg/g. The samples were fused to separate the platinum-group elements from matrix. The nickel sulfide button was then dissolved with hydrochloric acid and the insoluble platinum-group sulfide residue was dissolved with aqua regia by ultrasound bath and finally determined by ICP-OES. The proposed method has been applied into the determination of platinum-group element and gold in large amounts of ultrabasic rocks from the Great Dyke of Zimbabwe.

  2. Platinum/Palladium hollow nanofibers as high-efficiency counter electrodes for enhanced charge transfer

    Science.gov (United States)

    Navarro Pardo, F.; Benetti, D.; Zhao, H. G.; Castaño, V. M.; Vomiero, A.; Rosei, F.

    2016-12-01

    Pt/Pd hollow nanofibers were obtained by sputtering a Pt/Pd alloy (80/20 wt%) onto polymer nanofibers (used as sacrificial template) and were used as counter-electrodes (CEs) in dye-sensitized solar cells (DSSCs). We demonstrate that optimization of nanofiber density and Pt/Pd sputtering thickness can increase the short circuit current density and consequently lead to a ∼15% enhancement in power conversion efficiency (PCE), when compared to the commonly used flat Pt/Pd CEs with the same thickness. The processes that contribute to such PCE improvement are: (i) increased surface area provided by the high aspect ratio hollow nanofibers and (ii) improved electro-catalytic performance, as validated by electrochemical impedance spectroscopy (EIS) measurements. The latter showed a two-fold decrease in the charge-transfer resistance of the nanostructured-CE, compared to the flat CE. The contribution of the Pt/Pd hollow nanofiber to light scattering was negligible as shown by reflectance measurements. These results suggest a simple and straightforward strategy to increase PCE in DSSCs, to minimize the use of precious metals used in this kind of devices and, more generally, to tailor the CE structure in photoelectrochemical systems to boost their functional properties, thanks to the advantages afforded by this complex morphology.

  3. Antimicrobial and antitumor activity of platinum and palladium complexes of novel spherical aramides nanoparticles containing flexibilizing linkages: Structure-property relationship

    Science.gov (United States)

    Elhusseiny, Amel F.; Hassan, Hammed H. A. M.

    2013-02-01

    Square planar Pd (II) and octahedral Pt (IV) complexes with novel spherical aramides nanoparticles containing flexible linkages ligands have been synthesized and characterized using analytical and spectral techniques. The synthesized complexes have been tested for their antimicrobial activity using Kirby-Bauer disc diffusion method. The antitumor activity has been performed using liver carcinoma (HEPG2), breast carcinoma (MCF7) and colon carcinoma (HCT 116) cell lines. Palladium complexes of polyamides containing sulfones showed the highest potency as antibacterial and antifungal agents. Platinum complexes containing sulfone and ether flexible linkages and chloro groups exhibited high potency as antitumor and antimicrobial agents. The uniform sizes of these nanomaterials could find biological uses such as immune assay and other medical purposes.

  4. The synthesis and characterization of complexes of zinc(II, cadmium(II, platinum(II and palladium(II with potassium 3-dithiocarboxy-3-aza-5-aminopentanoate

    Directory of Open Access Journals (Sweden)

    SRECKO TRIFUNOVIC

    2004-02-01

    Full Text Available Complexes of zinc(II, cadmium(II, platinum(II and palladium(II with a new polydentate dithiocarbamate ligand, 3-dithiocarboxy-3-aza-5-aminopentanoate (daap-, of the type M(daap2·nH2O (M = Zn(II, Cd(II, n = 2, or M = Pt(II, Pd(II, n = 0, have been prepared and characterized by elemental analysis, IR and UV/VIS spectroscopy, as well as magnetic measurements. The spectra of the complexes suggest a bidentate coordination of the daap- ligand to the metal ions via the sulfur atoms of the deprotonated dithiocarbamato group. The fact that under the same experimental conditions its S-methyl ester does not form complexes could be taken as proof of the suggested coordination mode.

  5. C-H Bond Activation of Bisimines by Palladium (Ⅱ) and Platinum (Ⅱ).Synthesis,Characterization of Bis (imino) aryl-palladium (Ⅱ) Pincer Complexes and Their Application in Carbon-Carbon Cross Coupling Reactions%C-H Bond Activation of Bisimines by Palladium (Ⅱ) and Platinum (Ⅱ).Synthesis, Characterization of Bis (imino) aryl-palladium (Ⅱ) Pincer Complexes and Their Application in Carbon-Carbon Cross Coupling Reactions

    Institute of Scientific and Technical Information of China (English)

    CHEN Rong; CHEN Ying; LIU Fang; LI Ping; HU Zhao-xia; WANG Hong-xing

    2013-01-01

    Abstract:The reactions of a variety of 4,6-dimethyl-1,3-bis (imino) benzenes 2a-g derived from 4,6-dimethylisophthalaldehyde and anilines or benzylamine with palladium (Ⅱ) acetate in anhydrous acetic acid under nitrogen were investigated.Experiment results demonstrate that cyclopalladations in such condition are applicable not only to the present system under study but also to the 5-substituted bis(imino)benzenes 6,7.The molecular structure of 3 b was further confirmed by X-Ray single-crystal diffraction.3b Crystallizes in orthorhombic,space groupP2 (1) 2 (1) 2 (1) with a =0.734 53 (8),b =1.683 8 (3),c =1.691 7(2) nm,α =β =γ =90°.Treatment of 2b with K2PtCl4 in anhydrous acetic acid affords the corresponding NCN-platinum pincer.Carbon-carbon cross coupling reactions catalyzed with 3b were investigated.These palladium complexes have been proved to be high effective catalysts for Suzuki coupling reaction.

  6. Process for the separation and recovery of palladium and platinum from spent automobile catalyst leach liquor using LIX 84I and Alamine 336.

    Science.gov (United States)

    Reddy, B Ramachandra; Raju, B; Lee, Jin Young; Park, Hyung Kyu

    2010-08-15

    Spent catalysts from automobile industry contain environmentally critical and economically valuable metals such as Pt, Pd, Fe, Ni, Mn, and Cr. In this paper, we present a process for the selective separation and complete recovery of palladium (Pd) and platinum (Pt) from hydrochloric acid leach liquors of spent automobile catalyst employing solvent extraction method. Typical composition of leach liquor used for the present study contains (mg/L): Pd-150, Pt-550, Mn-500, Ni-1000, Fe-1500, Cr-100 and 3 M HCl. Selective separation of Pd from the leach liquor is achieved with 0.5 vol.% LIX 84I (2-hydroxy-5-nonylacetophenone oxime in a mixture with a high flash point hydrocarbon diluent) in kerosene at an aqueous to organic (A/O) ratio of 3 in 2 stages, with an enrichment factor of three. Quantitative stripping of Pd from loaded organic is achieved with 0.5 M thiourea and 1 M HCl. Co-extraction of Fe and Pt with 5 vol.% Alamine 336 (tertiary amine of mixed tri-octyl/decyl amine) in kerosene followed by selective scrubbing of Fe with dilute HCl and complete stripping of Pt from loaded organic was proposed with 0.5 M thiourea and 0.1 M HCl. Purity of Pd and Pt strip solutions are 99.7%. Finally, the present process can solve environmental related issues and at the same time recover valuable metals in pure form.

  7. 从炭载体废催化剂回收铂钯%Recovery of Palladium and Platinum from Carbon Supported Waste Catalysts

    Institute of Scientific and Technical Information of China (English)

    刘时杰

    2014-01-01

    The carbon supported catalysts, Pd/C and Pt/C, are the very important chemical catalysts. The incineration technology is the most simple method for the recovery of platinum or palladium from the waste catalysts. The processes and technologies to prevent the loss of flying-ash during burning were introduced and some examples were listed. The principle of supercritical water oxidation (SCWO) and its technical processes were discussed, and its application prospect was reviewed.%Pd/C、Pt/C是非常重要的化工催化剂。最简单的从废催化剂中回收钯或铂的方法是焚烧法。介绍了工艺过程及防止焚烧时飞扬损失的各种技术措施,列举了应用实例。探讨了超临界水氧化法(SCWO)的原理,工艺过程及处理炭载体废催化剂的应用前景。

  8. Tetrahedral Palladium Nanocrystals: A New Support for Platinum Monolayer Electrocatalysts with High Activity and Stability in the Oxygen Reduction Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Kuanping [Brookhaven National Lab. (BNL), Upton, NY (United States); Choi, YongMan [Brookhaven National Lab. (BNL), Upton, NY (United States); Vukmirovic, Miomir B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Liu, Ping [Brookhaven National Lab. (BNL), Upton, NY (United States); Ma, Chao [Brookhaven National Lab. (BNL), Upton, NY (United States); Su, Dong [Brookhaven National Lab. (BNL), Upton, NY (United States); Adzic, Radoslav R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2012-10-01

    The recent availability of tetrahedral palladium (PdTH) nanocrystals with cleaned surfaces allowed us to evaluate their facet-specific electrochemical properties as a new support of platinum monolayer (PtML) catalysts. The Pd–PtML core-shell electrocatalyst was examined by combining structural analyses and Density Functional Theory (DFT) with electrochemical techniques. The surfaces of the PdTH core are composed of (111) facets wherein the Pd atoms are highly coordinated and have low surface energy. Our results revealed that in comparison with sphere Pd (PdSP)-supported PtML or pure Pt, the PdTH-supported PtML features more surface contraction and a downshift of d-band relative to the Fermi level. These geometric- and electronic-effects determine the higher activity of PtML/PdTH/C for the oxygen reduction reaction (ORR) compared to that of PtML/PdSP/C. This shape-property interdependence illuminated new approaches to basic- and applied- research on Pt-based ORR electrocatalysts of significant importance to the widespread use of fuel cells.

  9. Preparation and characterization of platinum (Pt) and palladium (Pd) nanoparticle decorated graphene sheets and their utilization for the elimination of basic fuchsin and indigo carmine dyes

    Science.gov (United States)

    Kurt, Belma Zengin; Durmus, Zehra; Durmus, Ali

    2016-01-01

    In this study, graphene nano sheets, prepared with chemical oxidation and reduction routes via modified-Hummer method, were successfully decorated with platinum (Pt) and palladium (Pd) nanoparticles. Structural and morphological features of resulted graphene-metal nanocomposites were characterized with FT-IR, XRD, SEM and TEM methods. Anti-oxidant activity (AOA) values of nanocomposites were determined. The IC50 values of Pt-graphene and Pd-graphene nanocomposites were found to be 46.1 and 90.2 μg/mL, respectively based on the ABTS method and 80.2 and 143.7 μg/mL according to the DPPH method. It was found that the graphene-metal nanocomposites exhibited superior free radical scavenging activity compared to several types of noble metal nano particles although the nanocomposites consist of much lower amount of active metal sites than the nano-crystalline metal powders. It was consequently reported that the graphene-metal nanocomposites could be successfully used for the photocatalytic elimination of fuchsin and indigo carmine dyes under light irradiation.

  10. The use of high performance liquid chromatography and solid phase extraction for separation of platinum, palladium and rhodium

    OpenAIRE

    2012-01-01

    Platinum group metals (PGMs) have received much attention in the fields of industry, geochemistry and medicine. Due to scarcity of PGMs and their high industrial demands, recycling of PGM bearing materials such as industrial wastes, automobile catalytic converters and similar products gained much attention in recent times. Particularly, separation of PGMs as a group from the material bearing the elements followed by their individual separation is crucial. In this study, an attempt was made to...

  11. Linear homobimetallic 4-thioacetyl-substituted NCN pincer palladium(II) and platinum(II) complexes with N-bidentate connecting units (NCN = [C6H2(CH2NMe2)2-2,6-R-4]−)

    NARCIS (Netherlands)

    Döring, K.; Taher, D.; Walfort, B.; Lutz, M.; Spek, A.L.; van Klink, G.P.M.; van Koten, G.; Lang, H.

    2008-01-01

    The synthesis and characterization of homobimetallic palladium and platinum complexes of type [(Me(O)CS-4-NCN–M ← N∩N → M–NCN-4-SC(O)Me](OTf)2 (Me(O)CS-4-NCN = [C6H2(CH2NMe2)2-2,6-SC(O)Me-4]−; N∩N = 4,4′-bipyridine (bipy); M = Pd, 12; M = Pt, 13) is reported. The required bifunctional thio-acetyl NC

  12. {ital E}3 transition probabilities in the platinum, mercury, and lead isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Egido, J.L.; Martin, V.; Robledo, L.M.; Sun, Y. [Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)]|[Analisis Numerico, Facultad de Informatica, Universidad Politecnica de Madrid, E-28660 Madrid (Spain)]|[Department of Physics and Atmospheric Science, Drexel University, Philadelphia, Pennsylvania 19104 (United States)]|[Joint Institute for Heavy Ion Research, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    1996-06-01

    Spectroscopical properties of the platinum, mercury, and lead isotopes are studied within the Hartree-Fock plus BCS framework with the finite range density-dependent Gogny force. These properties are also studied beyond mean-field theory by combining the use of generator-coordinate-method-like wave functions with the angular momentum projection technique as to generate many-body correlated wave functions that are at the same time eigenstates of the angular momentum operator. We apply this formalism to the calculation of reduced transition probabilities {ital B}({ital E}3) from the lowest-lying octupole collective state to the ground state of several isotopes of the platinum, mercury, and lead nuclei whose experimental {ital B}({ital E}3) values present a peculiar behavior. The projected calculations show a large improvement over the unprojected ones when compared with the experimental data. The unprojected calculations are unable to predict any structure in the {ital B}({ital E}3). {copyright} {ital 1996 The American Physical Society.}

  13. Gold Functionalized Platinum M12L24-Nanospheres and Their Application in Cyclization Reactions

    NARCIS (Netherlands)

    Leenders, S.H.A.M.; Dürr, M.; Ivanović-Burmazović, I.; Reek, J.N.H.

    2016-01-01

    Nanospheres can be formed by combining 24 bispyridinyl building blocks with a palladium or platinum precursor. These spheres can be functionalized on the inside with a gold(I) chloride complex leading to a high local concentration of gold(I) complexes. The high local concentration makes the neutral

  14. Structural analysis of platinum-palladium nanoparticles dispersed on titanium dioxide to evaluate cyclo-olefines reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, N., E-mail: necastillo@yahoo.co [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Edificio B, 04510 Mexico DF (Mexico); Centro de Investigacion y de Estudios Avanzados del IPN, Depto. de Fisica, Av. IPN 2508, C.P. 07360, Mexico DF (Mexico); Perez, R. [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Campus Morelos, 62251 Cuernavaca Morelos (Mexico); Martinez-Ortiz, M.J.; Diaz-Barriga, L. [Instituto Politecnico Nacional - ESIQIE, UPALM Edif. 7, 07738 Mexico DF (Mexico); Garcia, L. [Instituto Politecnico Nacional - ESIT, UPALM, 07738 Mexico DF (Mexico); Conde-Gallardo, A. [Centro de Investigacion y de Estudios Avanzados del IPN, Depto. de Fisica, Av. IPN 2508, C.P. 07360, Mexico DF (Mexico)

    2010-04-16

    Structural and chemical properties were correlated to explain catalytic behavior of Pt-Pd/TiO{sub 2} in a cyclo-olefin reaction. Bimetallic nanoparticles supported on TiO{sub 2} were prepared by wetness impregnation techniques at different concentrations of Pt and Pd {approx}1 metallic wt%. The physicochemical properties of these metallic nanoparticles supported on TiO{sub 2} were characterized by N{sub 2} physisorption (Brunauer-Emmett-Teller-BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The relationship between chemical composition, physicochemical properties and particle size on the cyclo-olefin reaction was then studied. XRD and TEM results show that these nanoparticles are composed of Pt-Pd with FFC structure (a = 0.389-0.391 nm) supported on TiO{sub 2} (anatase-like structure), and the materials present tetragonal structure nanoparticles (a = 0.37842, b = 0.37842, c = 0.95146 nm). Samples with higher contents of platinum and particle sizes of 4.2 nm show the highest catalytic conversion in cyclo-olefins reaction. Finally, structural examinations of Pt{sub x}-Pd{sub (1-x)}/TiO{sub 2} based system was then conducted to study the effects of metals on the nanostructure of the materials.

  15. Determination of platinum and palladium in road dust after their separation on immobilized fungus by electrothermal atomic absorption spectrometry

    Science.gov (United States)

    Woińska, Sylwia; Godlewska-Żyłkiewicz, Beata

    2011-07-01

    A flow solid phase extraction procedure based on biosorption of Pt(IV) and Pd(II) on Aspergillus sp. immobilized on cellulose resin Cellex-T was proposed for the separation and preconcentration of Pt and Pd before their determination by electrothermal atomic absorption spectrometry (ETAAS). The analytical conditions including sample pH, eluent type, flow rates of sample and eluent solutions were examined. The analytes were selectively retained on the biosorbent in acidic medium (pH 1) and subsequently eluted from the column with 1 mL of thiourea solution (0.25 mol L - 1 thiourea in 0.3 mol L - 1 HCl). The reproducibility of the procedure was below 5%. The limit of detection of the method was 0.020 ng mL - 1 for Pt and 0.012 ng mL - 1 for Pd. The method validation was performed by analysis of certified reference materials BCR-723 (tunnel dust) and SARM-76 (platinum ore). The developed separation procedure was applied to the determination of Pt and Pd in road dust samples by ETAAS. The applied biosorbent is characterized by high sorption capacity: 0.47 mg g - 1 for Pt and 1.24 mg g - 1 for Pd.

  16. Determination of platinum and palladium in road dust after their separation on immobilized fungus by electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Woinska, Sylwia; Godlewska-Zylkiewicz, Beata, E-mail: bgodlew@uwb.edu.pl

    2011-07-15

    A flow solid phase extraction procedure based on biosorption of Pt(IV) and Pd(II) on Aspergillus sp. immobilized on cellulose resin Cellex-T was proposed for the separation and preconcentration of Pt and Pd before their determination by electrothermal atomic absorption spectrometry (ETAAS). The analytical conditions including sample pH, eluent type, flow rates of sample and eluent solutions were examined. The analytes were selectively retained on the biosorbent in acidic medium (pH 1) and subsequently eluted from the column with 1 mL of thiourea solution (0.25 mol L{sup -1} thiourea in 0.3 mol L{sup -1} HCl). The reproducibility of the procedure was below 5%. The limit of detection of the method was 0.020 ng mL{sup -1} for Pt and 0.012 ng mL{sup -1} for Pd. The method validation was performed by analysis of certified reference materials BCR-723 (tunnel dust) and SARM-76 (platinum ore). The developed separation procedure was applied to the determination of Pt and Pd in road dust samples by ETAAS. The applied biosorbent is characterized by high sorption capacity: 0.47 mg g{sup -1} for Pt and 1.24 mg g{sup -1} for Pd.

  17. Complexes of platinum and palladium with β-diketones and DMSO: Synthesis, characterization, molecular modeling, and biological studies

    Science.gov (United States)

    do Couto Almeida, J.; Marzano, I. M.; de Paula, F. C. Silva; Pivatto, M.; Lopes, N. P.; de Souza, P. C.; Pavan, F. R.; Formiga, A. L. B.; Pereira-Maia, E. C.; Guerra, W.

    2014-10-01

    This work reports on the synthesis and characterization of new complexes of the type [MCl(L)DMSO], where L = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (HTPB) or 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HTTA) and M = Pt2+ or Pd2+. These complexes were characterized by elemental analyses, conductivity measurements, FT-IR, UV-Vis, high-resolution mass spectra (HRESIMS) and TG/DTA. In the complexes, the metallic ions bind to β-diketone via the oxygen atoms and to DMSO molecule via sulfur atom. The structures of complexes were optimized and theoretical data showed good agreement with the experimental results. The cytotoxic activity of the compounds was evaluated in a chronic myelogenous leukemia cell line. The platinum complexes were more cytotoxic than the free ligands and carboplatin and are promising candidates for further investigations. As example, the compound [PtCl(TPB)(DMSO)] inhibits the growth of K562 cells with an IC50 value equal to 2.5 μM. Furthermore, microbiological assays against Mycobacterium tuberculosis showed that all complexes exhibit low cytotoxicity against this bacterial strain while the free ligands exhibited MIC values of approximately 10 μg mL-1.

  18. Occupational asthma caused by palladium

    Energy Technology Data Exchange (ETDEWEB)

    Daenen, M.; Rochette, F.; Demedts, M.; Nemery, B. [K.U. Leuven, Pneumology (Belgium); Rogiers, P. [A.Z. St-Lucas, Brugge (Belgium); Walle, C. Van de [Siemens, Oostkamp (Belgium)

    1999-01-01

    Occupational exposure to complex platinum salts is a well-known cause of occupational asthma. Although there is evidence that platinum refinery workers may also be sensitized to other precious metals, such as palladium or rhodium, no instances of occupational asthma due to an isolated sensitization to palladium have been reported. A case is reported of occupational rhinoconjunctivitis and asthma in a previously healthy worker exposed to the fumes of an electroplating bath containing palladium. There was no exposure to platinum. Sensitization to palladium was documented by skin-prick tests. The skin-prick test was positive with Pd(NH{sub 3}){sub 4}Cl{sub 2}, but not with (NH{sub 4}){sub 2}PdCl{sub 4}. Corresponding salts of platinum were all negative. A bronchial provocation test with Pd(NH{sub 34})Cl{sub 2} (0.0001 % for a total of 315 s, followed by 0.001 % for a total of 210 s) led to an early decrease in forced expiratory volume in one second (-35%). A similar exposure (0.001 % for a total of 16 min) in an unrelated asthmatic gave no reaction. This case shows that an isolated sensitization to palladium can occur and that respiratory exposure to palladium is a novel cause of metal-induced occupational asthma. (au) 24 refs.

  19. 电感耦合等离子体原子发射光谱法测定银合金中的铂钯%Determination of Platinum and Palladium in Silver Alloy by Inductively Coupled Plasma Atomic Emission Spectrometry

    Institute of Scientific and Technical Information of China (English)

    佡云; 褚晓君

    2016-01-01

    采用硝酸溶解样品,盐酸沉淀分离银,过滤洗涤后,在5%(体积分数)硝酸介质中,用电感耦合等离子体原子发射光谱法(ICP-AES)测定银合金样品中的铂、钯,该方法用于多个银合金中铂钯的测定,加标回收率在96%~101%,相对标准偏差(RSD,n=10)小于5%。%The sample was dissolved with nitric acidhydrochloric acid was added to the sample to produce precipitation of silver chloridethen filter and wash it.Platinum and palladium in silver alloy samples are determinated by inductively coupled plasma atomic emission spectrometryICP-AES in a 5% volume fraction nitric acid .The method was applied to the determination of platinum and palladium in silver al-lay samples.The recovery rate was in the range of 96%~101% and the relative standard deviationRSDn=10 was less than 5%.

  20. Electrochemical Deposition of Platinum and Palladium on Gold Nanoparticles Loaded Carbon Nanotube Support for Oxidation Reactions in Fuel Cell

    Directory of Open Access Journals (Sweden)

    Surin Saipanya

    2014-01-01

    Full Text Available Pt and Pd sequentially electrodeposited Au nanoparticles loaded carbon nanotube (Au-CNT was prepared for the electrocatalytic study of methanol, ethanol, and formic acid oxidations. All electrochemical measurements were carried out in a three-electrode cell. A platinum wire and Ag/AgCl were used as auxiliary and reference electrodes, respectively. Suspension of the Au-CNT, phosphate buffer, isopropanol, and Nafion was mixed and dropped on glassy carbon as a working electrode. By sequential deposition method, PdPtPt/Au-CNT, PtPdPd/Au-CNT, and PtPdPt/Au-CNT catalysts were prepared. Cyclic voltammograms (CVs of those catalysts in 1 M H2SO4 solution showed hydrogen adsorption and hydrogen desorption reactions. CV responses for those three catalysts in methanol, ethanol, and formic acid electrooxidations studied in 2 M CH3OH, CH3CH2OH, and HCOOH in 1 M H2SO4 show characteristic oxidation peaks. The oxidation peaks at anodic scan contribute to those organic substance oxidations while the peaks at cathodic scan are related with the reoxidation of the adsorbed carbonaceous species. Comparing all those three catalysts, it can be found that the PdPtPt/Au-CNT catalyst is good at methanol oxidation; the PtPdPt/Au-CNT effectively enhances ethanol oxidation while the PtPdPd/Au-CNT exceptionally catalyzes formic acid oxidation. Therefore, a different stoichiometry affects the electrochemical active surface area of the catalysts to achieve the catalytic oxidation reactions.

  1. Recent strikes in South Africa’s platinum-group metal mines: effects upon world platinum-group metal supplies

    Science.gov (United States)

    Yager, Thomas R.; Soto-Viruet, Yadira; Barry, James J.

    2012-01-01

    The recent labor disputes over wages and working conditions that have affected South Africa’s three leading platinum-group metal (PGM) producers have affected an industry already plagued by market pressures and labor unrest and raised the specter of constraints in the world’s supply of these metals. Although low demand for these metals in 2011 and 2012 helped to offset production losses of recent years, and particularly those losses caused by the strikes in 2012, a prolonged resumption of strikes could cause severe shortages of iridium, platinum, rhodium, ruthenium, and, to a lesser extent, palladium.

  2. Palladium-Mediated Catalysis Leads to Intramolecular Narcissistic Self-Sorting on a Cavitand Platform.

    Science.gov (United States)

    Nagymihály, Zoltán; Caturello, Naidel A M S; Takátsy, Anikó; Aragay, Gemma; Kollár, László; Albuquerque, Rodrigo Q; Csók, Zsolt

    2017-01-06

    Palladium-catalyzed aminocarbonylation reactions have been used to directly convert a tetraiodocavitand intermediate into the corresponding carboxamides and 2-ketocarboxamides. When complex mixtures of the amine reactants are employed in competition experiments using polar solvents, such as DMF, no "mixed" products possessing structurally different amide fragments are detected either by (1)H or (13)C NMR. Only highly symmetrical cavitands are sorted out of a large number of potentially feasible products, which represents a rare example of intramolecular, narcissistic self-sorting. Our experimental results along with thermodynamic energy analysis suggest that the observed self-sorting is a symmetry-driven, kinetically controlled process.

  3. The electrooxidation mechanism of formic acid on platinum and on lead ad-atoms modified platinum studied with the kinetic isotope effect

    Science.gov (United States)

    Bełtowska-Brzezinska, M.; Łuczak, T.; Stelmach, J.; Holze, R.

    2014-04-01

    Kinetics and mechanism of formic acid (FA) oxidation on platinum and upd-lead ad-atoms modified platinum electrodes have been studied using unlabelled and deuterated compounds. Poisoning of the electrode surface by CO-like species was prevented by suppression of dissociative chemisorption of FA due to a fast competitive underpotential deposition of lead ad-atoms on the Pt surface from an acidic solution containing Pb2+ cations. Modification of the Pt electrode with upd lead induced a catalytic effect in the direct electrooxidation of physisorbed FA to CO2. With increasing degree of H/D substitution, the rate of this reaction decreased in the order: HCOOH > DCOOH ≥ HCOOD > DCOOD. HCOOH was oxidized 8.5-times faster on a Pt/Pb electrode than DCOOD. This primary kinetic isotope effect proves that the C-H- and O-H-bonds are simultaneously cleaved in the rate determining step. A secondary kinetic isotope effect was found in the dissociative chemisorption of FA in the hydrogen adsorption-desorption range on a bare Pt electrode after H/D exchange in the C-H bond, wherein the influence of deuterium substitution in the O-H group was negligibly small. Thus the C-H bond cleavage is accompanied by the C-OH and not the O-H bond split in the FA decomposition, producing CO-like species on the Pt surface sites.

  4. Characteristics of platinum-group elements in basalts from spreading axis of Mariana Trough

    Institute of Scientific and Technical Information of China (English)

    CAO Zhimin; ZHENG Jianbin; ZHOU Meifu; AN Wei; QI Liang

    2007-01-01

    Total platinum-group elements (PGEs) abundances in basalts from the spreading axis of Mariana Trough ranged from 0.418 × 10-9 to 1.022 × 10-9, and primitive mantle-normalized PGE patterns are of positive slope showing the relative enrichment of PPGE (platinum, palladium, rhodium) and gold relative to IPGE. Compared with other mantle-originated rocks, these basalts have lower PGE contents and wider ranges of primitive mantle-normalized ratios of palladium content to iridium one, palladium content to platinum one and palladium content to gold one exhibiting relative platinum and iridium depletion. Characteristics of PGE patterns indicated that the studied Mariana Trough basalts originated from low partial melting, and the MORB mantle beneath the spreading center had been contaminated by the arc-island mantle. In the aspect of trace elements, Mariana Trough basalts showed the enrichment of LILE, lead and LREE, indicating that they had been influenced by subduction compositions. All these demonstrated that Mariana Trough basalts are products of partial melting from a mixed mantle ( the contamination of MORB mantle by arc-island mantle).

  5. Determination of trace gold, platinum and palladium in lean-platinum ore by bismuth fire assaying-inductively coupled plasma mass spectrometry%铋试金-电感耦合等离子体质谱法测定贫铂矿石中痕量金铂钯

    Institute of Scientific and Technical Information of China (English)

    李可及; 赵朝辉; 范建雄

    2013-01-01

    为解决传统铅试金法中所存在的污染问题,通过理论计算、优化操作流程等方式建立了针对贫铂矿石中痕量金、铂、钯的铋试金-电感耦合等离子体质谱测定方法.结果表明,选用40.0g氧化铋、30.0g硼酸、20.0 g无水碳酸钠和2.0g面粉作为试金配料的组分,贵金属的选择性好,排除重金属的能力强,可基本满足贫铂矿石样品(20.0 g)中痕量金、铂、钯的测定需要.实验还针对铋扣难以完全回收的问题,采用了在出炉时趁热倾倒熔渣,使铋扣于空气中自然冷却然后取出的方法.在进行质谱测定时,选择197 Au、195 Pt、105 pd分别作为金、铂、钯的测定同位素,以185 Re、115In作为校正基体效应与信号漂移的内标元素.方法检出限(ng/g,以20.0g取样量计)分别为:0.51(Au)、0.43 (Pt)、0.50(Pd),Pt、Pd、Au测定结果的相对标准偏差(RSD,n=5)分别为4.7%、5.4%、9.7%.对GBW07291和GBW07293铂族元素地球化学标准物质中Pt、Pd、Au进行测定,测定值与认定值基本一致.方法可用于地质样品中痕量Au、Pt、Pd的准确测定.%In order to solve the pollution problem in traditional lead fire assaying method,the determination method of trace gold,platinum and palladium in lean-platinum ore by bismuth fire assaying-inductively coupled plasma mass spectrometry was established through theoretical calculation and optimization of operation procedures.The results showed that,the selectivity of precious metal by fire assaying formula containing 40.0 g of bismuth oxide,30.0 g of boric acid,20.0 g of anhydrous sodium carbonate and 2.0 g of flour was good.This formula had strong exclusion ability to precious metals and could meet the determination requirements of trace gold,platinum and palladium in lean-platinum ore samples (20.0 g).Aiming at the problem that bismuth button was hardly recovered,the melt slag was poured while hot.The bismuth button was naturally cooled in air,thus it could

  6. A facile reflux procedure to increase active surface sites form highly active and durable supported palladium@platinum bimetallic nanodendrites

    Science.gov (United States)

    Wang, Qin; Li, Yingjun; Liu, Baocang; Xu, Guangran; Zhang, Geng; Zhao, Qi; Zhang, Jun

    2015-11-01

    A series of well-dispersed bimetallic Pd@Pt nanodendrites uniformly supported on XC-72 carbon black are fabricated by using different capping agents. These capping agents are essential for the branched morphology control. However, the surfactant adsorbed on the nanodendrites surface blocks the access of reactant molecules to the active surface sites, and the catalytic activities of these bimetallic nanodendrites are significantly restricted. Herein, a facile reflux procedure to effectively remove the capping agent molecules without significantly affecting their sizes is reported for activating supported nanocatalysts. More significantly, the structure and morphology of the nanodendrites can also be retained, enhancing the numbers of active surface sites, catalytic activity and stability toward methanol and ethanol electro-oxidation reactions. The as-obtained hot water reflux-treated Pd@Pt/C catalyst manifests superior catalytic activity and stability both in terms of surface and mass specific activities, as compared to the untreated catalysts and the commercial Pt/C and Pd/C catalysts. We anticipate that this effective and facile removal method has more general applicability to highly active nanocatalysts prepared with various surfactants, and should lead to improvements in environmental protection and energy production.

  7. Electrocatalysts having platium monolayers on palladium, palladium alloy, and gold alloy core-shell nanoparticles, and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Adzic, Radoslav (Setauket, NY); Mo, Yibo (Naperville, IL); Vukmirovic, Miomir (Port Jefferson Station, NY); Zhang, Junliang (Rochester, NY)

    2010-12-21

    The invention relates to platinum-coated particles useful as fuel cell electrocatalysts. The particles are composed of a noble metal or metal alloy core at least partially encapsulated by an atomically thin surface layer of platinum atoms. The invention particularly relates to such particles having a palladium, palladium alloy, gold alloy, or rhenium alloy core encapsulated by an atomic monolayer of platinum. In other embodiments, the invention relates to fuel cells containing these electrocatalysts and methods for generating electrical energy therefrom.

  8. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by react

  9. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by

  10. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by react

  11. Platinum and palladium nano-structured catalysts for polymer electrolyte fuel cells and direct methanol fuel cells.

    Science.gov (United States)

    Long, Nguyen Viet; Thi, Cao Minh; Yong, Yang; Nogami, Masayuki; Ohtaki, Michitaka

    2013-07-01

    In this review, we present the synthesis and characterization of Pt, Pd, Pt based bimetallic and multi-metallic nanoparticles with mixture, alloy and core-shell structure for nano-catalysis, energy conversion, and fuel cells. Here, Pt and Pd nanoparticles with modified nanostructures can be controllably synthesized via chemistry and physics for their uses as electro-catalysts. The cheap base metal catalysts can be studied in the relationship of crystal structure, size, morphology, shape, and composition for new catalysts with low cost. Thus, Pt based alloy and core-shell catalysts can be prepared with the thin Pt and Pt-Pd shell, which are proposed in low and high temperature proton exchange membrane fuel cells (PEMFCs), and direct methanol fuel cells (DMFCs). We also present the survey of the preparation of Pt and Pd based catalysts for the better catalytic activity, high durability, and stability. The structural transformations, quantum-size effects, and characterization of Pt and Pd based catalysts in the size ranges of 30 nm (1-30 nm) are presented in electro-catalysis. In the size range of 10 nm (1-10 nm), the pure Pt catalyst shows very large surface area for electro-catalysis. To achieve homogeneous size distribution, the shaped synthesis of the polyhedral Pt nanoparticles is presented. The new concept of shaping specific shapes and morphologies in the entire nano-scale from nano to micro, such as polyhedral, cube, octahedra, tetrahedra, bar, rod, and others of the nanoparticles is proposed, especially for noble and cheap metals. The uniform Pt based nanosystems of surface structure, internal structure, shape, and morphology in the nanosized ranges are very crucial to next fuel cells. Finally, the modifications of Pt and Pd based catalysts of alloy, core-shell, and mixture structures lead to find high catalytic activity, durability, and stability for nano-catalysis, energy conversion, fuel cells, especially the next large-scale commercialization of next

  12. Synthesis, characterization and antimicrobial activity of novel platinum(IV) and palladium(II) complexes with meso-1,2-diphenyl-ethylenediamine-N,N‧-di-3-propanoic acid - Crystal structure of H2-1,2-dpheddp·2HCl·H2O

    Science.gov (United States)

    Radić, Gordana P.; Glođović, Verica V.; Ratković, Zoran R.; Novaković, Slađana B.; Garcia-Granda, Santiago; Roces, Laura; Menéndez-Taboada, Laura; Radojević, Ivana D.; Stefanović, Olgica D.; Čomić, Ljiljana R.; Trifunović, Srećko R.

    2012-12-01

    In the reaction of meso-1,2-diphenyl-ethylenediamine (1,2-dphen) with neutralized 3-chlor-propanoic acid, the new linear tetradentate edda-like ligand (edda = ethylenediamine-N,N'-diacetic ion) meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoic acid dihydrochloride monohydrate (H2-1,2-dpheddp·2HCl·H2O) was prepared. The corresponding platinum(IV) complex, s-cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoate)-platinum(IV) ([PtCl2(1,2-dpheddp)]) was synthesized by heating potassium-hexachloridoplatinate(IV) and H2-1,2-dpheddp·2HCl·H2O on steam bath for 12 h with neutralization by means of lithium-hydroxide. The palladium(II) complex, cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoate)-palladium(II) ([PdCl2(1,2-dpheddp)]) was obtained in the similar way using potassium-tetrachloridopalladate(II), H2-1,2-dpheddp·2HCl·H2O and lithium-hydroxide. The compounds were characterized by elemental analysis and infrared spectroscopy. The spectroscopically predicted structure of the synthesized tetradentate ligand was confirmed by X-ray analysis of the H2-1,2-dpheddp·2HCl·H2O. Antimicrobial activity of the ligand and corresponding palladium(II) and platinum(IV) complexes is investigated against 25 species of microorganisms. Testing is preformed by microdilution method and minimum inhibitory concentrations (MIC) and minimum microbicidal concentration (MMC) have been determined. The difference between antimicrobial activity of the ligand and corresponding platinum(IV) and palladium(II) complex is noticed and, in general, palladium(II) complex was the most active.

  13. Synthesis, structural, spectral, thermal and antimicrobial studies of palladium(II), platinum(II), ruthenium(III) and iridium(III) complexes derived from N,N,N,N-tetradentate macrocyclic ligand.

    Science.gov (United States)

    Rani, Soni; Kumar, Sumit; Chandra, Sulekh

    2011-05-01

    Palladium(II), platinum(II), ruthenium(III) and iridium(III) complexes of general stoichiometry [PdL]Cl(2), [PtL]Cl(2), [Ru(L)Cl(2)]Cl and [Ir(L)Cl(2)]Cl are synthesized with a tetradentate macrocyclic ligand, derived from 2,6-diaminopyridine with 3-ethyl 2,4-pentanedione. Ligand was characterized on the basis of elemental analyses, IR, mass, and (1)H NMR and (13)C NMR spectral studies. All the complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, electronic spectral techniques and thermal studies. The value of magnetic moments indicates that all the complexes are diamagnetic except Ru(III) complex which shows magnetic moments corresponding its one unpaired electron. The macrocyclic ligand and all its metal complexes were also evaluated in vitro against some plant pathogenic fungi and bacteria to assess their biocidal properties.

  14. Platinum metals in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Zereini, Fathi [Frankfurt Univ. (Germany). Dept. of Environmental Analytical Chemistry; Wiseman, Clare L.S. (ed.) [Toronto Univ. (Canada). School of the Environment

    2015-03-01

    This book contains the five chapters with the following topics: 1. SOURCES OF PGE EMISSIONS ELEMENTS: Sources of Platinum Group Elements (PGE) in the Environment; Impact of Platinum Group Element Emissions from Mining and Production Activities. 2. ANALYTICAL METHODS FOR THE DETERMINATION OF PGE IN BIOLOGICAL AND ENVIRONMENTAL MATRICES: Appraisal of Biosorption for Recovery, Separation and Determination of Platinum, Palladium and Rhodium in Environmental Samples; On the Underestimated Factors Influencing the Accuracy of Determination of Pt and Pd by Electrothermal Atomic Absorption Spectrometry in Road Dust Samples; Application of Solid Sorbents for Enrichment and Separation of Platinum Metal Ions; Voltammetric Analysis of Platinum in Environmental Matrices; Speciation Analysis of Chloroplatinates; Analysis of Platinum Group Elements in Environmental Samples: A Review. 3. OCCURRENCE, CHEMICAL BEHAVIOR AND FATE OF PGE IN THE ENVIRONMENT: Brazilian PGE Research Data Survey on Urban and Roadside Soils; Platinum, Palladium and Rhodium in a Bavarian Roadside Soil; Increase of Platinum Group Element Concentrations in Soils and Airborne Dust During the Period of Vehicular Exhaust Catalysts Introduction; Platinum-Group Elements in Urban Fluvial Bed Sediments-Hawaii; Long-Term Monitoring of Palladium and Platinum Contents in Road Dust of the City of Munich, Germany; Characterization of PGEs and Other Elements in Road Dusts and Airborne Particles in Houston, Texas; Accumulation and Distribution of Pt and Pd in Roadside Dust, Soil and Vegetation in Bulgaria; Increase of the Environmental Pt Concentration in the Metropolitan Area of Mexico City Associated to the Use of Automobile Catalytic Converters; Solubility of Emitted Platinum Group Elements (Pt, Pd and Rh) in Airborne Particulate Matter (PM10) in the Presence of Organic Complexing Agents; The Influence of Anionic Species (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup 2-}) on the Transformation and Solubility of Platinum in

  15. 氢还原重量法测定海绵铂、钯产品的灼烧损失量%Determination of Weight Loss Ignition in Sponge Platinum and Palladium Production by Hydrogen Reduction Gravimetry

    Institute of Scientific and Technical Information of China (English)

    郭俊梅; 韩守礼; 谭文进; 贺小塘; 李琨; 刘文; 李勇; 王欢; 吴喜龙

    2014-01-01

    Conditions for determination of weight loss ignition in sponge platinum and palladium production by hydrogen reduction gravimetry were systemic investigated. Effect of contents coming from oxygen, nitrogen, carbon and otherwise nonmetal coexist impurities on analytical result was investigated, and the determined results of the method were compared with that of thermo gravimetry. Results indicate that the weights loss ignition are of 0.0018%~0.0769% and 0.0018%~0.0694%, respectively, in sponge platinum and palladium under the conditions of 2 g sample, hydrogen reduction, subsection heating temperature to 800℃.Relative permissible deviation (RPD), relative standard deviation (RSD,n=11) and repeatability limit (r) are 2.1%~50%, 0.7%~16.0%, 0.0006%~0.0026%, for Pt, and 3.0%~15.8%, 1.0%~5.3%, 0.0003%~0.0020%, for Pd, respectively. The weights loss ignition was composed of oxygen and nitrogen contents, and it is not affected from charcoal content. The proposed method is easy to operated, reliable of analysis results, good accord with those of thermo gravimetry, and to satisfy the analytical requirement for 99.90%~99.99% sponge platinum and palladium production.%研究了氢还原重量法测定海绵铂、钯产品灼烧损失量的条件,考察了氧、氮、碳等非金属共存杂质元素含量对分析结果的影响,并与热重分析方法进行了对比。结果表明:称取2 g样品,氢还原分段升温至800℃,重量法测定海绵铂、钯的灼烧损失量分别为0.0018%~0.0769%和0.0018%~0.0694%,测定铂的相对允许差(RPD)、相对标准偏差(RSD)和重复性限(r)分别为2.1%~50%、0.7%~16.0%和0.0006%~0.0026%,对于钯分别为3.0%~15.8%、1.0%~5.3%和0.0003%~0.0020%。灼烧损失量主要由氧、氮含量组成,微量的炭对其影响忽略不计。氢还原重量法测定灼烧损失量操作简便,结果可靠,结果与热重分析方法的吻合,能够满足99.90%~99.99%的海绵铂、钯产品的分析要求。

  16. Research on New Technology for Extracting Precious Metals from Low Grade Gold Platinum Palladium Material%从低品位金铂钯物料中提取贵金属新工艺研究

    Institute of Scientific and Technical Information of China (English)

    马玉天; 陈大林; 郭晓辉; 潘从明; 张燕; 王立

    2014-01-01

    金川集团股份有限公司产生的低品位金钯铂物料为蒸残渣,通常是由贵金属精矿蒸馏分离锇、钌,水溶液氯化产生。现有蒸残渣处理工艺为反复氯化,由于受氯化效率的影响,依然有部分贵金属残留在外付渣中,造成贵金属流失。为提高贵金属回收率,金川集团贵金属冶炼厂组织进行了从蒸残渣中提纯贵金属的实验研究。通过长期实验探索,确定了蒸残渣氯化焙烧-盐酸浸出-有机溶剂萃取分离金铂钯的工艺路线。之后,又进行了工业化扩大试验,确定了最佳工艺技术条件,金、铂、钯直收率≥95%。与水溶液氯化工艺相比,该工艺具有贵金属直收率高、劳动强度低、生产周期短及生产成本低等特点。%The company produced platinum and palladium low grade gold material that was a kind of steamed residue,additionally,the steamed residue was produced during the process of precious metals concentrate distillation separation of osmium,ruthenium and aqueous chlorination.The existing steamed residue treatment technique of chloride repeatedly,because the effect of the efficiency of chloride,there were still some precious metal residues in the outside pay residue,has the problem of precious metals lossing.In order to improve the precious metal recovery,the smelting plant in the company completed a series of experimental studies on purification of precious metals from the steamed residue.Thus,after the experimental exploration for a long time, the steamed residue chloridizing roasting-hydrochloric acid leaching gold platinum palladium-organic solvent extraction separation process was determined.Then,the industrialized expanding test and the optimum technology conditions were also determined,meanwhile,the direct recovery rate was more than or equal to 95%during the technological process of gold,platinum and palladium.Compared with aqueous chlorination process,the method applied in the paper

  17. GFAAS Determination of Platinum, Palladium, Rhodium and Iridium in Ores%石墨炉原子吸收光谱法测定矿石中铂、钯、铑、铱

    Institute of Scientific and Technical Information of China (English)

    羊波; 杨新周; 李银科; 叶艳清; 胡秋芬

    2012-01-01

    矿石样品铂、钯、铑和铱经铅试金富集,所得金属合粒用硝酸-盐酸溶解,用石墨炉原子吸收光谱法测定矿石样品中铂、钯、铑和铱的含量。在优化的石墨炉工作条件下测得:铂的质量浓度在20-150μg·L-1、钯在15-120μg·L-1、铑和铱在6-100μg·L-1范围内与其吸光度呈线性关系,检出限(3s/k)依次为4.6,4.0,1.5,1.5μg·L-1。方法用于分析了2种矿石国家标准物质(GBW07341、GBW07342),测定结果与认定值相符。方法的回收率在87.6%~105.5%之间。测定值的日内和日间相对标准偏差(n=7)分别在2.8%~3.6%和3.5%~4.7%之间。%Platinum, palladium, rhodium and iridium in ore samples were enriched by the lead fire assaying method, and the alloy of precious metals obtained was dissolved in HNO3 and HCl. The contents of Pt, Pd, Rh and Ir in the sample solution were determined by GFAAS. It was found that under the optimum working conditions of the graphite furnace, linear relationships between values of absorbance and mass concentration were obtained in the ranges of 20--150 μg·L-1 for Pt, 15--120μg·L-1 for Pd, 6-100 μg·L-1 for Rh and It. Detection limits (3s/ k) found were 4. 6/lg ~ L-1 (Pt), 4. 0μg·L-1(Pd) and 1.5μg·L-1(Rh and It). The proposed method was used in the analysis of 2 ore CRM's (GBW 07341, GBW 07342) and the results obtained were in conformity with the certified values. Values of recovery found by standard addition method were in the range of 87. 6%--105. 5%. Values of intra-day and inter-day RSD's (n=7) found were in the ranges of 2. 8%--3. 6% and 3. 5%--4. 7% respectively.

  18. 电感耦合等离子体发射光谱法测定铂钯合金中的铑和铱%Determination of Rhodium and Iridium in Platinum Palladium Alloys by ICP-AES

    Institute of Scientific and Technical Information of China (English)

    宫嘉辰; 张颖; 王艳红; 褚晓君

    2015-01-01

    Simultaneous determination of Rh and Ir in environmental samples was carried out by inductively coupled plasma atomic emission spectrometry ( ICP -AES) after platinum palladium alloys dissolved with hydriochloric acid and nitric acid . Optimal experimental conditions including analytical spectral line , back‐ground interference and instrument parameter were investigated and established according to the different proportion of Rh and Ir in alloys .The present methodology gave recoveries between 99 .83% and 100 .15%and RSD less than 1 .5% , w hich make the result satisfactory .%铂钯合金用盐酸、硝酸溶解,采用电感耦合等离子体发射光谱法测定合金中的铑和铱。针对该合金中铂、钯所占比例不同,准确建立了铑、铱的元素分析谱线、背景干扰、仪器参数等实验条件。测定的铑、铱相对标准偏差均小于1.5%,加标后的回收率在99.83%~100.15%,分析结果令人满意。

  19. Synthesis of platinum(II) and palladium(II) complexes with 9,9-dihexyl-4,5-diazafluorene and their in vivo antitumour activity against Hep3B xenografted mice.

    Science.gov (United States)

    Wang, Q-W; Lam, P-L; Wong, R S-M; Cheng, G Y-M; Lam, K-H; Bian, Z-X; Ho, C-L; Feng, Y-H; Gambari, R; Lo, Y-H; Wong, W-Y; Chui, C-H

    2016-11-29

    Two complexes dichloro(9,9-dihexyl-4,5-diazafluorene)platinum(II) (Pt-DHF) and dichloro(9,9-dihexyl-4,5-diazafluorene)palladium(II) (Pd-DHF) were synthesized and their in vivo antitumour activity was investigated using an athymic nude mice model xenografted with human Hep3B carcinoma cells. Pt-DHF- and Pd-DHF-treated groups showed significant tumour growth inhibition (with about 9-fold and 3-fold tumour growth retardation) when compared with the vehicle control group. The liver toxicology effects on the animals of the two compounds were investigated. Pt-DHF and Pd-DHF-treated groups had a lower alanine transaminase and aspartate transaminase values than those of the vehicle treated group as the animals from the vehicle control group had very heavy hepatoma burden. We assume that both complexes could be further investigated as effective antitumour agents and it is worthwhile to study their underlying working mechanism.

  20. New palladium(II) and platinum(II) 5,5-diethylbarbiturate complexes with 2-phenylpyridine, 2,2'-bipyridine and 2,2'-dipyridylamine: synthesis, structures, DNA binding, molecular docking, cellular uptake, antioxidant activity and cytotoxicity.

    Science.gov (United States)

    Icsel, Ceyda; Yilmaz, Veysel T; Kaya, Yunus; Samli, Hale; Harrison, William T A; Buyukgungor, Orhan

    2015-04-21

    Novel palladium(ii) and platinum(ii) complexes of 5,5-diethylbarbiturate (barb) with 2-phenylpyridine (Hppy), 2,2'-bipyridine (bpy) and 2,2'-dipyridylamine (dpya) have been prepared and characterized by elemental analysis, IR, UV-Vis, NMR and ESI-MS. Single-crystal diffraction measurements show that complex consists of binuclear [Pd2(μ-barb-κN,O)2(ppy-κN,C)2] moieties, while complexes are mononuclear, [M(barb-κN)2(L-κN,N')] (L = bpy or dpya). has a composition of [Pt(dpya-κN,N')2][Ag(barb-κN)2]2·4H2O and was assumed to have a structure of [Pt(barb-κN)(Hppy-κN)(ppy-κN,C)]·3H2O. The complexes were found to exhibit significant DNA binding affinity by a non-covalent binding mode, in accordance with molecular docking studies. In addition, complexes and displayed strong binding with supercoiled pUC19 plasmid DNA. Cellular uptake studies were performed to assess the subcellular localization of the selected complexes. A moderate radical scavenging activity of and was confirmed by DPPH and ABTS tests. Complexes , , and showed selectivity against HT-29 (colon) cell line.

  1. Determination of Palladium in Resin by Lead Fire Assaying-Flame Atomic Absorption Spectrometric Method%铅试金富集-火焰原子吸收光谱法测定树脂中钯

    Institute of Scientific and Technical Information of China (English)

    王芳; 陈小兰; 林海山; 李小玲; 肖红新

    2013-01-01

    通过铅试金富集树脂中的钯并用银作钯灰吹保护,得到的银钯合粒用王水溶解,在5%的盐酸介质中,采用原子吸收光谱法测定钯,该法测钯的相对标准偏差RSD为0.53%,加标回收率在99.04%~100.10%之间。%Palladium in resin was enriched by lead assaying, using silver as a protective agent to produce silver-palladium alloy, and then the alloy was dissolved in aqua regia. Air acetylene flame atomic absorption spectrometric method was used to determinate palladium in 5%hydrochloric acid solution. The relative standard deviation (RSD) in determination of palladium is 0.53%and the recovery rate is between 99.04%~100.10%.

  2. Electroanalytical method for determination of lead(II) in orange and apple using kaolin modified platinum electrode.

    Science.gov (United States)

    El Mhammedi, M A; Achak, M; Bakasse, M; Chtaini, A

    2009-08-01

    This paper reports on the use of platinum electrode modified with kaolin (K/Pt) and square wave voltammetry for analytical detection of trace lead(II) in pure water, orange and apple samples. The electroanalytical procedure for determination of the Pb(II) comprises two steps: the chemical accumulation of the analyte under open-circuit conditions followed by the electrochemical detection of the preconcentrated species using square wave voltammetry. The analytical performances of the extraction method has been explored by studying the incubating time, and effect of interferences due to other ions. During the preconcentration step, Pb(II) was accumulated on the surface of the kaolin. The observed detection and quantification limits in pure water were 3.6x10(-9)molL(-1) and 1.2x10(-8)molL(-1), respectively. The precision of the method was also determined; the results was 2.35% (n=5).

  3. Problems, possibilities and limitations of inductively coupled plasma atomic emission spectrometry in the determination of platinum, palladium and rhodium in samples with different matrix composition

    Science.gov (United States)

    Petrova, P.; Velichkov, S.; Velitchkova, N.; Havezov, I.; Daskalova, N.

    2010-02-01

    The economic and geological importance of platinum group of elements has led to the development of analytical methods to quantify them in different types of samples. In the present paper the quantitative information for spectral interference in radial viewing 40.68 MHz inductively coupled plasma atomic emission spectrometry in the determination of Pt, Pd and Rh in the presence of complex matrix, containing Al, Ca, Fe, Mg, Mn, P and Ti as matrix constituents was obtained. The database was used for optimum line selections. By using the selected analysis lines the following detection limits in ng g - 1 were obtained: Pt 1700, Pd-1440, Rh-900. The reached detection limits determine the possibilities and limitation of the direct ICP-AES method in the determination of Pt, Pd and Rh in geological and environmental materials. The database for spectral interferences in the presence of aluminum can be used for the determination of platinum group of elements in car catalysts. The accuracy of the analytical results was experimentally demonstrated by two certified reference materials that were analyzed: SARM 7, Pt ore and recycled auto-catalyst certified reference material SRM 2556.

  4. Problems, possibilities and limitations of inductively coupled plasma atomic emission spectrometry in the determination of platinum, palladium and rhodium in samples with different matrix composition

    Energy Technology Data Exchange (ETDEWEB)

    Petrova, P.; Velichkov, S. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bontchev Str. bl. 11, 1113 Sofia (Bulgaria); Velitchkova, N. [Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bontchev Str., bl.24, 1113 Sofia (Bulgaria); Havezov, I. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bontchev Str. bl. 11, 1113 Sofia (Bulgaria); Daskalova, N., E-mail: das15482@svr.igic.bas.b [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bontchev Str. bl. 11, 1113 Sofia (Bulgaria)

    2010-02-15

    The economic and geological importance of platinum group of elements has led to the development of analytical methods to quantify them in different types of samples. In the present paper the quantitative information for spectral interference in radial viewing 40.68 MHz inductively coupled plasma atomic emission spectrometry in the determination of Pt, Pd and Rh in the presence of complex matrix, containing Al, Ca, Fe, Mg, Mn, P and Ti as matrix constituents was obtained. The database was used for optimum line selections. By using the selected analysis lines the following detection limits in ng g{sup -1} were obtained: Pt 1700, Pd-1440, Rh-900. The reached detection limits determine the possibilities and limitation of the direct ICP-AES method in the determination of Pt, Pd and Rh in geological and environmental materials. The database for spectral interferences in the presence of aluminum can be used for the determination of platinum group of elements in car catalysts. The accuracy of the analytical results was experimentally demonstrated by two certified reference materials that were analyzed: SARM 7, Pt ore and recycled auto-catalyst certified reference material SRM 2556.

  5. Palladium-catalyzed air-based oxidative coupling of arylboronic acids with H-phosphine oxides leading to aryl phosphine oxides.

    Science.gov (United States)

    Fu, Tingting; Qiao, Hongwei; Peng, Zhimin; Hu, Gaobo; Wu, Xueji; Gao, Yuxing; Zhao, Yufen

    2014-05-14

    We present a novel and highly efficient methodology that allows for the construction of C-P bonds via the palladium-catalyzed air-based oxidative coupling of various commercially available arylboronic acids with easily oxidized H-phosphine oxides leading to valuable aryl phosphine oxides, particularly triarylphosphine oxides, with the use of air as the green oxidant, broad substrate applicability and good to excellent yields. The described catalytic system should be an efficient complement to the Chan-Lam type reaction and be useful in synthetic programs.

  6. Electrochemical generation of volatile lead species using a cadmium cathode: Comparison with graphite, glassy carbon and platinum cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Saenz, Maria; Fernandez, Lenys, E-mail: lfernandez@usb.ve; Dominguez, Jose; Alvarado, Jose

    2012-05-15

    Working electrodes made out of pyrolytic graphite, glassy carbon, platinum and cadmium were compared for the electrochemical generation of volatile lead species. The same electrolytic cell, using each of the different working electrodes was coupled to an atomic absorption spectrometer and the experimental conditions were optimized in each case, using a univariate approach, to produce the maximum possible amount of volatile lead species. The experiments were focused on the variation of cathode hydrogen overvoltage by the application of a constant current during analysis. Under optimum conditions the performance of the electrochemical hydride generator cell should depend on the cathode material selected due to the different hydrogen overpotential of each material. The lead absorbance signal was taken as a measure of the efficiency of volatile lead species production. Best results were obtained using the Cd cathode, due to its relatively highest hydrogen overpotential, a carrier gas (Ar) flow rate of 55 mL min{sup -1} an electrolytic current of 0.8 A and a catholyte (HCl) concentration 0.05 mol L{sup -1}. The analytical figures of merit of the method using the Cd electrode were evaluated and the susceptibility of the method to interferences was assessed by its application to the determination of trace amounts of lead in the presence of the most significant interferents. The calibration curve was linear between 0.5 and 15 {mu}g L{sup -1} Pb. Detection limits and characteristic mass values were 0.21 {mu}g L{sup -1} and 0.26 {mu}g L{sup -1} respectively. A bovine liver standard reference material and a spiked urine sample were analyzed to check accuracy. - Highlights: Black-Right-Pointing-Pointer Cadmium cathode for the electrochemical generation (ECHG) of lead volatile species. Black-Right-Pointing-Pointer Cadmium cathode for the ECHG of lead hydrides improve merit figures. Black-Right-Pointing-Pointer The ECHG of the volatile species depends on the hydrogen

  7. VARIABLE PRESSURE OXYGEN-17 FTNMR AND STOPPED-FLOW KINETIC STUDY OF WATER EXCHANGE AND DMSO SUBSTITUTION ON SQUARE-PLANAR TETRAAQUA-PALLADIUM (II) AND -PLATINUM (II)

    OpenAIRE

    Ducommun, Y.; Nichols, P; Helm, L.; Elding, L.; Merbach, A.

    1984-01-01

    The very slow water exchange on Pt(H2O)2+4 was studied in the temperature range 273 to 334 K and pressure range 0.1 to 228 MPa by 17O FTNMR, following the increase in height of the signal from bound water observed when platinum(II) solutions are mixed with 170 enriched water. The much faster water exchange on Pd(H2O)2+4 studied in the temperature range 240 to 345 K and pressure range 0.1 to 260 MPa, by measuring the 17O FTNMR linewidths of the bound water resonance at 27.1 and 48.7 MHz. Compl...

  8. 树脂分离光度法测定金、钯、铂%Determination of gold ( Ⅲ ), platinum ( Ⅳ ) and palladium ( Ⅱ ) using spectrophotometry mothod with resin separation

    Institute of Scientific and Technical Information of China (English)

    马东兰; 王昀; 丁国生; 马狂飙; 王瑾晔

    2011-01-01

    用 Amberlyst A-26大孔阴离子交换树脂分离金(Ⅲ)、铂(Ⅳ)和钯(Ⅱ).在 HAc-NaAc缓冲液中,用易溶于水的显色剂N-烯丙基-N′-(对氨基苯磺酸钠)硫脲(ASATu)和N-间甲苯基-N′-(对氨基苯磺酸钠)硫脲(MMPT)测定.前者测定金(Ⅲ),后者同时测定铂(Ⅳ)和钯(Ⅱ).该法用于催化剂和阳极泥样品的测定,结果满意.其相对标准偏差(RSD)小于2.4%,回收率在96.0%~98.2%.铂(Ⅳ)和钯(Ⅱ)不需要予先分离可同时测定.%Separation of Au( Ⅲ ), Pt( Ⅳ ) and Pd( Ⅱ ) with Amberlyst A-26 macropore anion-exchange resin in solution was carried out. Determination of these ions was proceeded in the medium of an HAc-NaAc buffer solution, with water-soluble color reagents ASATu and MMPT, ASATu was used for the determination of Au(Ⅲ); the MMPT was used for simultaneous determination of Pt( Ⅳ ) and Pd( Ⅱ ). The method has good selectivity and sensitivity. It can be used for the determination of contents of Au ( Ⅲ ), Pt ( Ⅳ ) and Pd ( Ⅱ ) in catalyst materials and anode mud with satisfactory results. The relative standard deviations (RSDs) were less than 2.4%, and the recoveries (%)were in the range of 96.0% ~98.2%. Simultaneous determination of Platinum (Ⅳ) and Palladium ( Ⅱ ) could be easily achieved without pre-separation.

  9. Determination of Gold, Platinum and Palladium in Copper Slag by ICP-AES with Coprecipitation Separation and Enrichment%共沉淀分离富集-ICP-AES法测定铜灰渣中金、铂、钯

    Institute of Scientific and Technical Information of China (English)

    何一芳; 张学彬

    2014-01-01

    An analysis method for determination of gold, platinum and palladium in copper slag by inductively coupled plasma atomic emission spectrometry (ICP-AES) with tellurium co-precipitation separation and enrichment was developed. The factors affecting determination were investigated, and the optimal detection conditions were determined. The detection limits were 5.6 (Au) µg/L,8.2 (Pt) µg/L and 3.6 (Pd) µg/L, the recovery ratio was 93.2%~102%, the relative standard derivation (RSD) was 1.21%(Au)~3.45% (Pt). The determination results were in good agreement with fire assaying. The method was accurate, simple and fast, and easy to master.%建立了碲共沉淀分离富集、电感耦合等离子体原子发射光谱法(ICP-AES)测定铜灰渣样品中微量元素金、铂、钯的方法。研究了影响测量的各种因素,确定了最佳测定条件。方法的检出限为:Au 5.6µg/L、Pd 8.2µg/L、Pt 3.6µg/L,回收率93.2%~102%,相对标准偏差(RSD)为:1.21%(Au)~3.45%(Pd),方法测定结果与火试金法一致。方法准确、简便快速,易于掌握。

  10. Determination of Lead, Copper and Iron Contents in Palladium-Carbon by ICP-AES%ICP-AES法测定钯炭中铅、铜和铁量

    Institute of Scientific and Technical Information of China (English)

    任传婷; 徐光; 唐发静; 李青; 马媛; 方卫; 李光俐; 甘建壮

    2015-01-01

    A simple accurate and precise analytical method for the determination of lead, copper and iron in palladium-carbon catalysts by ICP-AES was proposed. The digestion of sample which contains lead, copper and iron in the range between 0.01%~0.1% in fresh or spent palladium-carbon, was obtained using both HNO3 and HClO4. The recoveries were ranged from 95.8% to 100.9%. The precision, expressed as relative standard deviation (RSD) of the method, is better than 5%.%采用硝酸-高氯酸分解试样,ICP-AES法同时测定铅、铜和铁.建立了一个准确、快速、简便的测定方法,适用于新制和失效钯炭中铅、铜和铁量的测定.Pb、Cu、Fe测定范围为0.01%~0.1%;方法的加标回收率为95.8%~100.9%;相对标准偏差RSD<5%.

  11. Determination of Platinum Metals in Carbonaceous Mineral Raw Materials by Stripping Voltammetry

    OpenAIRE

    Kolpakova, Nina Alexandrovna; Oskina, Yuliya Aleksandrovna; Dyachenko, Elena Nikolaevna; Pshenichkin, Anatoliy Yakovlevich

    2015-01-01

    The paper considers the possibility of determining platinum metals in mineral raw materials by stripping voltammetry on a graphite electrode modified by metals. Stripping voltammetry method is characterized by low determination limit, wide intervals of determined content and high sensitivity. As a result of the research the conditions for the determination of gold, platinum and palladium by stripping voltammetry have been selected. The comparison of the results of gold, palladium and platinum...

  12. Electrochemical generation of volatile lead species using a cadmium cathode: Comparison with graphite, glassy carbon and platinum cathodes

    Science.gov (United States)

    Sáenz, María; Fernández, Lenys; Domínguez, José; Alvarado, José

    2012-05-01

    Working electrodes made out of pyrolytic graphite, glassy carbon, platinum and cadmium were compared for the electrochemical generation of volatile lead species. The same electrolytic cell, using each of the different working electrodes was coupled to an atomic absorption spectrometer and the experimental conditions were optimized in each case, using a univariate approach, to produce the maximum possible amount of volatile lead species. The experiments were focused on the variation of cathode hydrogen overvoltage by the application of a constant current during analysis. Under optimum conditions the performance of the electrochemical hydride generator cell should depend on the cathode material selected due to the different hydrogen overpotential of each material. The lead absorbance signal was taken as a measure of the efficiency of volatile lead species production. Best results were obtained using the Cd cathode, due to its relatively highest hydrogen overpotential, a carrier gas (Ar) flow rate of 55 mL min- 1 an electrolytic current of 0.8 A and a catholyte (HCl) concentration 0.05 mol L- 1. The analytical figures of merit of the method using the Cd electrode were evaluated and the susceptibility of the method to interferences was assessed by its application to the determination of trace amounts of lead in the presence of the most significant interferents. The calibration curve was linear between 0.5 and 15 μg L- 1 Pb. Detection limits and characteristic mass values were 0.21 μg L- 1 and 0.26 μg L- 1 respectively. A bovine liver standard reference material and a spiked urine sample were analyzed to check accuracy.

  13. Investigations on the bioavailability of traffic-related platinum group elements (PGE) to the aquatic fauna with special consideration being given to palladium; Untersuchungen zur Bioverfuegbarkeit Kfz-emittierter Platingruppenelemente (PGE) fuer die aquatische Fauna unter besonderer Beruecksichtigung von Palladium

    Energy Technology Data Exchange (ETDEWEB)

    Sures, B.; Thielen, F.; Zimmermann, S. [Karlsruhe Univ. (T.H.) (Germany). Zoologisches Inst.

    2002-07-01

    The uptake and accumulation of the traffic-related platinum group elements (PGE) Pt, Pd and Rh by the aquatic fauna was investigated. Zebra mussels, eels and barbels were maintained in water containing either road dust or ground catalytic converter material. Following the exposure, samples of fish liver and kidney, as well as the soft tissues of the mussels, were analysed. Our results revealed that all three catalytic noble metals were accumulated by aquatic organisms. The highest bioavailability was found for Pd, followed by Pt and Rh. The concentration factor of Pd for Dreissena polymorpha was 5 times higher compared with Pb and only 6 times lower than the essential element Cu. With regard to the increasing emission of Pd the level of this metal has to be monitored very carefully in the environment. (orig.) [German] Die Aufnahme und Anreicherung der Kfz-buertigen Platingruppenelemente (PGE) Pt, Pd und Rh durch aquatische Tiere wurde an Dreikantmuscheln, Aalen und Barben untersucht. Hierzu wurden die Testorganismen in Wasser mit Strassenstaub einer stark befahrenen Strasse oder mit zerriebenem Autokatalysatormaterial ueber mehrere Wochen exponiert und anschliessend Leber und Niere der Fische sowie das Weichgewebe der Muscheln analysiert. Im Rahmen dieser Studien konnte nachgewiesen werden, dass alle drei Edelmetalle durch Fische wie durch Muscheln aufgenommen und angereichert werden. Fuer Pd fand sich die hoechste Bioverfuegbarkeit, gefolgt von Pt und Rh. Das Ausmass der Aufnahme von Pd durch Dreissena polymorpha war ca. 5fach hoeher als von Pb und 6fach niedriger verglichen mit dem essenziellen Element Cu. In Anbetracht der steigenden Emission von Pd sollte ein Umweltmonitoring die Verbreitung von Pd in der Umwelt klaeren. (orig.)

  14. Experimental investigations of the hydrothermal geochemistry of platinum and palladium: V. Equilibria between platinum metal, Pt(II), and Pt(IV) chloride complexes at 25 to 300°C

    Science.gov (United States)

    Gammons, Christopher H.

    1996-05-01

    The solubility of metallic Pt in HCl solutions was determined at 200 to 300°C at oxidation states buffered near the aqueous Pt(II)/Pt(IV) boundary. Equilibrium constants were obtained for the following disproportionation reactions: log K, 200° 250° 300°C 2PtCl 42- = PtCl 42- + Pt(s) + 2Cl - 1.47 1.70 1.54 (a) 2PtCl 3- = PtCl 5- + Pt(s) + Cl - 1.77 1.74 1.37 (b) with experimental uncertainties of approximately ±0.20 log units. These results are found to be in good agreement with previously published estimates for reaction at 60 to 152.5°C. The data indicate that the relative stability of the Pt(II) and Pt(IV) chloride complexes does not change appreciably with temperature. This is in contrast to previous work in the Au(0)/Au(I)/Au(III) system which demonstrates that the Au(I) chloride complexes are unstable with respect to Au (III) at low temperature, but become the dominant aqueous species at 300°C. Pt(IV) chloride complexes are unlikely to be important in high temperature hydrothermal fluids, as unrealistically high aqueous platinum concentrations are required to stabilize these species relative to Pt(II). In contrast, thermodynamic calculations suggest that Pt(IV) chloride or hydroxychloride complexes may be the dominant form of dissolved platinum in low temperature brines that are strongly oxidized (e.g., seawater). In oxygenated, Cl-rich solutions, the solubility of Pt is extremely high at pH < 6, such that the mobility of this metal will most likely be limited by surface adsorption reactions and/ or its abundance and rate of dissolution in the enclosing rock or soil. At neutral to alkaline pH, calculated solubilities are much lower, and saturation with Pt oxide phases may occur, as has recently been described in nature.

  15. Highly active carbon supported palladium catalysts decorated by a trace amount of platinum by an in-situ galvanic displacement reaction for formic acid oxidation

    Science.gov (United States)

    Li, Zuopeng; Li, Muwu; Han, Mingjia; Wu, Xin; Guo, Yong; Zeng, Jianhuang; Li, Yuexia; Liao, Shijun

    2015-03-01

    Aimed at reducing platinum usage and improved catalytic activity for formic acid oxidation, a series of Pt decorated Pd/C catalysts are prepared by an in-situ galvanic displacement reaction between freshly prepared Pd/C ink and H2PtCl6 in an aqueous solution. The catalysts with 4 nm particle sizes and 20 wt.% loadings have been characterized by transmission electron microscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy (XPS). The electrochemical evaluations by cyclic voltammetry are conducted to test out the CO tolerance and catalytic activities. In addition to XPS analysis, a theoretical calculation has been attempted the first time to find out the surface Pd/Pt molar ratios. The decay rate of the catalysts has been evaluated by the percentage of the forward/backward peak current retained using the value at the 20th cycle divided by that in the first cycle. Compared with a Pd/C benchmark, all Pt decorated Pd/C register enhanced activity while the cost remains virtually unchanged. The optimized catalyst is found to have a Pd/Pt molar ratio of 75:1 but with 2.5 times activity relative to that of Pd/C.

  16. Behaviour of palladium(II), platinum(IV), and rhodium(III) in artificial and natural waters: influence of reactor surface and geochemistry on metal recovery.

    Science.gov (United States)

    Cobelo-Garcia, Antonio; Turner, Andrew; Millward, Geoffrey E; Couceiro, Fay

    2007-03-07

    The recovery of dissolved platinum group elements (PGE: Pd(II), Pt(IV) and Rh(III)) added to Milli-Q water, artificial freshwater and seawater and filtered natural waters has been studied, as a function of pH and PGE concentration, in containers of varying synthetic composition. The least adsorptive and/or precipitative loss was obtained for borosilicate glass under most of the conditions employed, whereas the greatest loss was obtained for low-density polyethylene. Of the polymeric materials tested, the adsorptive and/or precipitative loss of PGE was lowest for fluorinated ethylene propylene (Teflon). The loss of Pd(II) in freshwater was significant due to its affinity for surface adsorption and its relatively low solubility. The presence of natural dissolved organic matter increases the recovery of Pd(II) but enhances the loss of Pt(IV). The loss of Rh(III) in seawater was significant and was mainly due to precipitation, whereas Pd(II) recovery was enhanced, compared to freshwater, because of its complexation with chloride. The results have important implications regarding protocols employed for sample preservation and controlled laboratory experiments used in the study of the speciation and biogeochemical behaviour of PGE.

  17. Palladium(II)-Catalyzed Annulation of Alkynes with 2-(Cyanomethyl)phenylboronates Leading to 3,4-Disubstituted 2-Naphthalenamines.

    Science.gov (United States)

    Tsukamoto, Hirokazu; Ikeda, Taishi; Doi, Takayuki

    2016-03-04

    1,2-Bis(diphenylphosphino)ethane (dppe)-ligated palladium(II) complexes catalyze the annulation of internal alkynes with 2-(cyanomethyl)phenylboronates to provide 3,4-disubstituted-2-naphthalenamines in good yields. The annulation reaction proceeds under mild and neutral conditions and requires methanol as an essential solvent. In addition to symmetrical alkynes, unsymmetrical alkynes substituted by aryl, alkyl, and alkynyl groups participate in the annulation to afford the corresponding 2-naphthalenamines with electron-withdrawing sp(2)- and sp-carbons preferentially located at the C-3 position. Substituents including an alkyl or alkoxy group on the cyanomethyl moiety and a halogen atom on the benzene ring in the boronates are compatible with the reaction conditions. The annulation proceeds through the transmetalation of the palladium(II) complexes with the boronates and alkyne insertion followed by nucleophilic addition of the generated alkenylpalladium(II) species to the intramolecular cyano group. Stoichiometric reactions revealed that the methanol solvent was effective for both transmetalation and catalyst regeneration.

  18. Biological activity of palladium(II) and platinum(II) complexes of the acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate and the X-ray crystal structure of the [Pd(asme)2] (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) complex.

    Science.gov (United States)

    Akbar Ali, Mohammad; Mirza, Aminul Huq; Butcher, Raymond J; Tarafder, M T H; Keat, Tan Boon; Ali, A Manaf

    2002-11-25

    Palladium(II) and platinum(II) complexes of general empirical formula, [M(NS)(2)] (NS=uninegatively charged acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate; M=Pt(II) and Pd(II)) have been prepared and characterized by a variety of physicochemical techniques. Based on conductance, IR and electronic spectral evidence, a square-planar structure is assigned to these complexes. The crystal and molecular structure of the [Pd(asme)(2)] complex (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) has been determined by X-ray diffraction. The complex has a distorted cis-square planar structure with the ligands coordinated to the palladium(II) ions as uninegatively charged bidentate NS chelating agents via the azomethine nitrogen and the mercaptide sulfur atoms. The distortion from a regular square-planar geometry is attributed to the restricted bite angles of the ligands. Antimicrobial tests indicate that the Schiff bases exhibit strong activities against the pathogenic bacteria, Bacillus subtilis (mutant defective DNA repair), methicillin-resistant Staphylococcus aureus, B. subtilis (wild type) and Pseudomonas aeruginosa and the fungi, Candida albicans (CA), Candida lypotica (2075), Saccharomyces cerevisiae (20341) and Aspergillus ochraceous (398)-the activities exhibited by these compounds being greater than that of the standard antibacterial and antifungal drugs, streptomycin and nystatin, respectively. The palladium(II) and platinum(II) complexes are inactive against most of these organisms but, the microbe, Pseudomonas aeruginosa shows strong sensitivity to the platinum(II) complexes. Screening of the compounds for their cytotoxicities against T-lymphoblastic leukemia cancer cells has shown that the acetone Schiff base of S-methyldithiocarbazate (Hasme) exhibits a very weak activity, whereas the S-benzyl derivative (Hasbz) is inactive. However, the palladium(II) complexes exhibit strong cytotoxicities against this cancer; their

  19. Novel palladium(II) and platinum(II) complexes with 1H-benzimidazol-2-ylmethyl-N-(4-bromo-phenyl)-amine: structural studies and anticancer activity.

    Science.gov (United States)

    Abdel Ghani, Nour T; Mansour, Ahmed M

    2012-01-01

    [MLCl(2)] (L = (1H-benzimidazol-2-ylmethyl)-N-(4-bromo-phenyl)-amine; M = Pd & Pt) and [PdL(OH(2))(2)]∙2X∙zH(2)O (X = Br, I, z = 2; X = SCN, z = 1; X = NO(3), z = 0) complexes have been synthesized as potential anticancer compounds and their structures were elucidated using elemental analysis, spectral, thermal analysis and X-ray powder diffraction. The benzimidazole (L) crystallizes in the space group P2(1)/c with a = 8.6660(3) Å, b = 16.6739(7) Å, c = 9.8611(4) Å and β = 113.505(3) ° and forms an infinite chain structure with a trans-zigzag type along the crystallographic axis "a", through the intermolecular H-bond. FT-IR and (1)H NMR studies revealed that the ligand L is coordinated to the metal ion via the pyridine-type nitrogen (N(py)) of the benzimidazole ring and secondary amino group (NH(sec)). Quantum mechanical calculations of energies, geometries, vibrational wavenumbers, and (1)H NMR of the benzimidazole L and its complexes were carried out by DFT/B3LYP method combined with 6-31G(d) and LANL2DZ basis sets. Natural bond orbital (NBO) analysis and frontier molecular orbitals (FMO) were performed at B3LYP/LANL2DZ level of theory. The benzimidazole L, in comparison to its metal complexes was screened for its antibacterial activity. The complexes showed cyctotoxic effects against human breast cancer (MCF7), hepatocarcinoma (HepG(2)) and colon carcinoma cells (HCT). The platinum complex (6) exhibited a moderate antitumor activity against MCF7 with IC(50) = 10.2 μM comparing to that reported for cis-platin 9.91 μM.

  20. High-pressure/high-temperature synthesis and characterization of the first palladium or platinum containing lithium transition-metal sulfides Li2M3S4 (M=Pd, Pt)

    Science.gov (United States)

    Heymann, Gunter; Niehaus, Oliver; Krüger, Hannes; Selter, Philipp; Brunklaus, Gunther; Pöttgen, Rainer

    2016-10-01

    The new lithium transition-metal sulfides Li2M3S4 (M=Pd, Pt) were obtained via multianvil high-pressure/high-temperature syntheses at 8 GPa and 1150 °C starting from a stoichiometric mixture of lithium nitride, sulfur, and palladium or platinum. Single crystal structure analyses indicated the space group P21/c (no. 14) with the following lattice parameters and refinement results: a=492.9(1), b=1005.9(2), c=614.9(2) pm, β=110.9 (1)°, R1=0.0165, wR2=0.0308 (all data) for Li2Pd3S4 and a=498.2(1), b=1005.5(2), c=613.0(2) pm, β=110.8(1)°, R1=0.0215, wR2=0.0450 (all data) for Li2Pt3S4. The crystal structures are built up from two distinct Pd/Pt sites, one of which is a special position (0,0,0), two sulfur sites, and one lithium site. The atoms Pd2/Pt2 form isolated square planar PdS4/PtS4 units, whereas the Pd1/Pt1 atoms form pairs of square planar PdS4/PtS4 units, which are connected via a common edge. These two structural motives built up a three-dimensional network structure by linking through common corners. The lithium atoms are positioned inside of the so formed channels. Li2M3S4 (M=Pd, Pt) are isostructural to the minerals jaguéite, Cu2Pd3Se4 and chrisstanleyite, Ag2Pd3Se4, which are up to now the only representatives of this structure type. Both compounds were studied with respect to their magnetic properties and can be classified as Pauli paramagnetic or diamagnetic. Regarding the possibility of lithium mobility inside the channels, of the structure, solid state 7Li NMR and high-temperature single crystal investigations revealed localization of the lithium atoms on their crystallographic sites.

  1. 微波马弗炉处理—火焰原子吸收光谱法测定废旧电路板中金银铂钯%Determination of gold, silver, platinum, palladium in waste circuit boards samples by flame atomic absorption spectrometry with microwave muffle furnace pretreatment

    Institute of Scientific and Technical Information of China (English)

    叶艳青; 羊波; 杨新周; 李银科; 胡秋芬

    2012-01-01

    A novel method for the determination of gold, silver, platinum and palladium in waste circuit board samples was investigated in this paper by flame atomic absorption spectrometry with microwave muffle furnace pretreatment. 5. 0 g of crashed waste circuit board samples was weighed and burned in microwave muffle furnace at 550 ℃ for 30 min to decompose organic matter. After the burning things were dissolved with aqua regia, gold, silver, platinum and palladium in the sample solution were determined by flame atomic absorption spectrometry. The detection limit of gold, silver, platinum and palladium was 0. 078, 0. 12, 0. 15 and 0. 15 mg/mL, respectively. The recoveries were between 90% and 108%. The method was applied to the same waste circuit board sample for 7 times. The relative standard deviations on the same day were between 2. 2% and 2. 9%, and the relative standard deviations on different day between 3,3% and 3. 5%. The method was applied to the analysis of waste circuit board and the results were consistent with those obtained by microwave digestion inductively coupled plasma atomic emission spectrometry.%研究了微波马弗炉加热处理样品,火焰原子吸收光谱法测定废旧电路板中金、银、铂、钯的方法.称取5.0g粉碎后废旧电路板样品,用微波马弗炉在550℃灼烧30 min分解有机物,用王水溶解样品,样品溶液中的金、银、铂、钯用火焰原子吸收光谱法进行测定.金、银、铂、钯的方法检出限分别为0.078、0.12、0.15和0.15 mg/mL;方法回收率在90%~108%之间;用本方法平行测定同一废旧电路板样品7次,日内相对标准偏差为2.2%~2.9%;日间相对标准偏差为3.3%~3.5%.将本方法用于废旧电路板分析,测得结果与微波消解—电感耦合等离子体发射光谱法一致.

  2. 火焰原子吸收光谱法测定尾气净化金属载体催化剂中铂钯铑%Determination of platinum, palladium, rhodium in metal carrier catalyst for exhaust gas purification by flame atomic absorption spectrometry

    Institute of Scientific and Technical Information of China (English)

    施意华; 王晟; 杨仲平; 靳晓珠; 胡圣虹; 邓水平

    2012-01-01

    建立了火焰原子吸收光谱法测定尾气净化金属载体催化剂中Pt、Pd、Rh含量的新方法.研究了试样分解方法、共沉淀条件、测定干扰因素及消除方法.采用盐酸-超声波处理尾气净化金属载体催化剂,过滤,不溶物用过氧化钠分解,盐酸酸化后全部转化为样品溶液.在含2~3 mol/L盐酸的样品溶液.中,加入10 mg氧化碲和10 mL 200 g/L氯化亚锡溶液共沉淀富集样品溶液中的Pt、Pd、Rh,与基体元素Fe、Ni、Al、Cr、Na等完全分离,共沉淀物用王水溶解后,采用火焰原子吸收光谱法测定Pt、Pd、Rh.方法的检出限分别为:Pt 4.72 μg/g,Pd1.13μg/g,Rh 1.06 μg/g.将本方法用于实际样品分析,结果与电感耦合等离子体原子发射光谱法测定值一致,相对标准偏差(RSD,n=11)分别为:3.0%(Pt),1.9%(Pd),4.2%(Rh).%A novel method for the determination of platinum, palladium and rhodium in metal carrier catalyst for exhaust gas purification was established by flame atomic absorption spectrometrometry (FAAS). The sample decomposition method) coprecipitation condition, interference factor and elimination method were studied. The metal carrier catalyst sample for exhaust gas purification was treated by hydrochloric acid-ultrasonic wave, and filtrated. The insoluble substance was decomposed with sodium peroxide and acidized with hydrochloric acid, and then it was mixed with sample solution. 10 mg of tellurium oxide and 10 mL of 200 g/L SnCl2 solution were added to sample solution in the medium of 2-3 mol/L hydrochloric acid for the coprecipitation, enrichment and separation of palladium, platinum and rhodium from matrix elements such as Fe, Ni, Al, Cr and Na. After the coprecipitate was dissolved with aqua regia, the content of palladium, platinum and rhodium was determined by flame a-tomic absorption spectrometry. The detection limits of method for Pt, Pd and Rh are 4. 72,1.13 and 1. 06,respectively. The proposed method was applied to

  3. Vapour Treatment Method Against Other Pyro- and Hydrometallurgical Processes Applied to Recover Platinum From Used Auto Catalytic Converters

    Institute of Scientific and Technical Information of China (English)

    Agnieszka FORNALCZYK; Mariola SATERNUS

    2013-01-01

    Today more and more cars are produced every year.All of them have to be equipped with catalytic converters,the main role of which is to obtain substances harmless to the environment instead of exhausted gases.Catalytic converters contain platinum group metals (PGM) especially platinum,palladium and rhodium.The price of these metals and their increasing demand are the reasons why today it is necessary to recycle used auto catalytic converters.There are many available methods of recovering PGM metals from them,especially platinum.These methods used mainly hydrometallurgical processes; however pyrometallurgical ones become more and more popular.The article presents results of the research mainly concerning pyrometallurgical processes.Two groups of research were carried out.In the first one different metals such as lead,magnesium and copper were used as a metal collector.During the tests,platinum went to those metals forming an alloy.In other research metal vapours were blown through catalytic converter carrier (grinded or whole).In the tests metals such as calcium,magnesium,cadmium and zinc were applied.As a result white or grey powder (metal plus platinum) was obtained.The tables present results of the research.Processing parameters and conclusions are also shown.To compare efficiency of pyrometallurgical and hydrometallurgical methods catalytic converter carrier and samples of copper with platinum obtained from pyrometallurgical method were solved in aqua regia,mixture of aqua regia and fluoric acid.

  4. Epitaxial overgrowth of platinum on palladium nanocrystals

    Science.gov (United States)

    Jiang, Majiong; Lim, Byungkwon; Tao, Jing; Camargo, Pedro H. C.; Ma, Chao; Zhu, Yimei; Xia, Younan

    2010-11-01

    This paper describes a systematic study on the epitaxial overgrowth of Pt on well-defined Pd nanocrystals with different shapes (and exposed facets), including regular octahedrons, truncated octahedrons, and cubes. Two different reducing agents, i.e., citric acid and L-ascorbic acid, were evaluated and compared for the reduction of K2PtCl4 in an aqueous solution in the presence of Pd nanocrystal seeds. When citric acid was used as a reducing agent, conformal overgrowth of octahedral Pt shells on regular and truncated octahedrons of Pd led to the formation of Pd-Pt core-shell octahedrons, while non-conformal overgrowth of Pt on cubic Pd seeds resulted in the formation of an incomplete octahedral Pt shell. On the contrary, localized overgrowth of Pt branches was observed when L-ascorbic acid was used as a reducing agent regardless of the facets expressed on the surface of Pd nanocrystal seeds. This work shows that both the binding affinity of a reducing agent to the Pt surface and the reduction kinetics for a Pt precursor play important roles in determining the mode of Pt overgrowth on Pd nanocrystal surface.

  5. Determination of Ruthenium, Rhodium, Palladium, Iridium and Platinum in Copper-Nickel Sulfide Ores by Bismuth-Antimony Fire Assay%铋锑试金测定硫化铜镍矿中钌铑钯铱铂

    Institute of Scientific and Technical Information of China (English)

    李可及; 刘淑君; 邵坤

    2014-01-01

    建立了用于预富集硫化铜镍矿中钌铑钯铱铂5种铂族元素的铋锑试金方法。40.0 g 氧化铋、25.0 g硼酸、10.0 g 碳酸钠、1.00 g 淀粉与10.0 g 待测样品于120 mL 瓷皿中,充分混匀,850℃入炉,20 min 后升至1000℃,保留40 min,出炉后趁热倾倒熔渣,使铋试金于空气中自然冷却。设计两段灰吹流程,铋试金先在镁砂灰皿内灰吹,直至剩余直径约5 mm,而后直接转入盛有20 g 熔融锑粉的坩埚盖中继续灰吹,获得直径约1 mm 的试金合粒。所得合粒经微波消解,冷却后定容至10 mL。铂钯用 ICP-OES 分析;钌铑铱质量数选择99 Ru,103 Rh 和191 Ir,以115 In 和185 Re 为内标,应用 ICP-MS 分析。对标准物质 GBW07196平行测定12次,铂族元素相对标准偏差为7.0%~9.5%。在10 g 取样量条件下,方法对 Ru, Rh, Pd, Ir 和 Pt 的检出限分别为0.027,0.016,0.11,0.10和0.11 ng/ g。应用本方法处理标准物质 GBW07194,GBW07195和 GBW07196均获得了满意的结果。%A bismuth-antimony fire assay method for the preconcentration of ruthenium, rhodium, palladium, iridium and platinum in copper-nickel sulfide ores was developed. 40. 0 g bismuth trioxide, 25. 0 g boric acid, 10. 0 g sodium carbonate and 1. 00 g starch were mixed with 10. 0 g sample in a 120 mL porcelain bowl, which was put in a furnace at 850 ℃. After 20 min the temperature was raised to 1000 ℃ and held for another 40 min, and then the bowl was taken out, with the slag poured, which left the bismuth button to air cooling. A two-step cupellation procedure was developed. During the first step, the bismuth button was cupellated in a magnesia cupel until its diameter reached 5 mm or so, then it was transferred to a crucible cover containing 20 g melting antimony and kept cupellating, at last a bead with a diameter of 1 mm was obtained. The bead was microwave-digested, after cooling down to room temperature, the solvent of which was transferred to a volumetric flask and

  6. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples.

    Science.gov (United States)

    Ghaedi, Mehrorang; Shokrollahi, Ardeshir; Niknam, Khodabakhsh; Niknam, Ebrahim; Najibi, Asma; Soylak, Mustafa

    2009-09-15

    The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of cadmium(II), lead(II), palladium(II) and silver(I). The analytical procedure involved the formation of understudy metals complex with bis((1H-benzo [d] imidazol-2yl)ethyl) sulfane (BIES), and quantitatively extracted to the phase rich in octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. Methanol acidified with 1molL(-1) HNO(3) was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The concentration of BIES, pH and amount of surfactant (Triton X-114) was optimized. At optimum conditions, the detection limits of (3 sdb/m) of 1.4, 2.8, 1.6 and 1.4 ng mL(-1) for Cd(2+), Pb(2+), Pd(2+) and Ag(+) along with preconcentration factors of 30 and enrichment factors of 48, 39, 32 and 42 for Cd(2+), Pb(2+), Pd(2+) and Ag(+), respectively, were obtained. The proposed cloud point extraction has been successfully applied for the determination of metal ions in real samples with complicated matrix such as radiology waste, vegetable, blood and urine samples.

  7. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Ghaedi, Mehrorang, E-mail: m_ghaedi@mail.yu.ac.ir [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Shokrollahi, Ardeshir [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Niknam, Khodabakhsh [Chemistry Department, Persian Gulf University, Bushehr (Iran, Islamic Republic of); Niknam, Ebrahim; Najibi, Asma [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Soylak, Mustafa [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

    2009-09-15

    The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of cadmium(II), lead(II), palladium(II) and silver(I). The analytical procedure involved the formation of understudy metals complex with bis((1H-benzo [d] imidazol-2yl)ethyl) sulfane (BIES), and quantitatively extracted to the phase rich in octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. Methanol acidified with 1 mol L{sup -1} HNO{sub 3} was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The concentration of BIES, pH and amount of surfactant (Triton X-114) was optimized. At optimum conditions, the detection limits of (3 sdb/m) of 1.4, 2.8, 1.6 and 1.4 ng mL{sup -1} for Cd{sup 2+}, Pb{sup 2+}, Pd{sup 2+} and Ag{sup +} along with preconcentration factors of 30 and enrichment factors of 48, 39, 32 and 42 for Cd{sup 2+}, Pb{sup 2+}, Pd{sup 2+} and Ag{sup +}, respectively, were obtained. The proposed cloud point extraction has been successfully applied for the determination of metal ions in real samples with complicated matrix such as radiology waste, vegetable, blood and urine samples.

  8. Fate of platinum metals in the environment.

    Science.gov (United States)

    Pawlak, Justyna; Łodyga-Chruścińska, Elżbieta; Chrustowicz, Jakub

    2014-07-01

    For many years now automotive exhaust catalysts have been used to reduce the significant amounts of harmful chemical substances generated by car engines, such as carbon monoxide, nitrogen oxides, and aromatic hydrocarbons. Although they considerably decrease environmental contamination with the above-mentioned compounds, it is known that catalysts contribute to the environmental load of platinum metals (essential components of catalysts), which are released with exhaust fumes. Contamination with platinum metals stems mainly from automotive exhaust converters, but other major sources also exist. Since platinum group elements (PGEs): platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru) and iridium (Ir) seem to spread in the environment and accumulate in living organisms, they may pose a threat to animals and humans. This paper discusses the modes and forms of PGE emission as well as their impact on the environment and living organisms.

  9. Arresting mantle formation and redirecting embryonic shell gland tissue by platinum2+ leads to body plan modifications in Marisa cornuarietis (Gastropoda, Ampullariidae).

    Science.gov (United States)

    Marschner, Leonie; Triebskorn, Rita; Köhler, Heinz-R

    2012-08-01

    To evaluate the threat that anthropogenic substances pose to animals when they are emitted into the environment, tests like the invertebrate embryo toxicity test with the ramshorn snail Marisa cornuarietis have been developed. These tests are used to investigate substances like the heavy metal platinum (Pt) that is used in catalytic converters and is gradually released in car exhausts. In 2010, our group reported that high Pt concentrations cause body plan alterations in snails and prevent the formation of an external shell during M. cornuarietis embryogenesis. Now, this study presents scanning-electron micrographs and histological sections of platinum(2+) (Pt(2+))-treated and untreated M. cornuarietis embryos and compares "normally" developing and "shell-less" embryos during embryogenesis, to reveal the exact course of events that lead to this body plan shift. Both groups showed similar development until the onset of torsion 70- to 82-h postfertilization. In the Pt(2+)-exposed embryos, the rudimentary shell gland (=anlage of both shell gland and mantle, which usually evaginates, grows, and eventually covers the visceral sac) does not spread across the visceral sac but remains on its ventral side. Without the excessive growth of the shell gland, a horizontal rotation of the visceral sac relative to head and foot does not occur, as being normal during the process of torsion.

  10. Platinum group metal nitrides and carbides: synthesis, properties and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanovskii, Alexander L [Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation)

    2009-04-30

    Experimental and theoretical data on new compounds, nitrides and carbides of the platinum group 4d and 5d metals (ruthenium, rhodium, palladium, osmium, iridium, platinum), published over the past five years are summarized. The extreme mechanical properties of platinoid nitrides and carbides, i.e., their high strength and low compressibility, are noted. The prospects of further studies and the scope of application of these compounds are discussed.

  11. Mineral resource of the month: platinum group metals

    Science.gov (United States)

    Loferski, Patricia J.

    2010-01-01

    The article focuses on platinum group metals (PGMs) and their properties. According to the author, PGMs, which include iridium, osmium, palladium, platinum, rhodium, and ruthenium, are among the rarest mineral commodities in the Earth's crust. PGMs are primarily used as catalytic converters that clean harmful exhaust from vehicle engines. They are also used in the chemical industry as catalysts in the production of nitric acid and in the petroleum refining industry.

  12. Determination of gold,platinum and palladium in geological samples by inductively coupled plasma mass spectrometry after concentration with 717 anion exchange resin%717阴离子交换树脂富集-电感耦合等离子体质谱法测定地质样品中痕量金铂钯

    Institute of Scientific and Technical Information of China (English)

    李丹; 王锝; 李彪

    2011-01-01

    The adsorption property and separation conditions of 717 anion exchange resin to trace gold,platinum and palladium in geological samples were studied. The sample was dissolved with HCl+ aqua regia under heating in water bath. Only Mo in dissolved elements had interference with the determination of Pd, which could be eliminated using mathematical formula correction. When the flow rate of eluent was 2 mL/min, the enrichment effects of gold, platinum and palladium in 5 % HCl medium reached its best, and the recoveries were close to 100 %. After correcting the influence of coexisting ions, the national first-class certified reference materials were determined by inductively coupled plasma mass spectrometry, and the difference between determination results and certified values was satisfactory. The detection limit of method were 0. 6 ng/mL, 0. 5 ng/mL and 0. 7 ng/mL for Pd, Pt and Au, respectively. Five random geological samples were analyzed by this method in comparison with NiS fire assay-ICP-MS method. The determination results were consistent. The results of two methods were checked by double sample's variance F test, and there was no significant difference.%研究了717型阴离子交换树脂对地质样品中痕量金、铂、钯的吸附性能及分离条件.采用水浴加热,HCl+王水的方式溶解样品,溶出的干扰元素只有Mo对Pd的测定造成干扰,采用数学公式校正可消除此干扰.在5%的HCl介质中,洗脱剂流速为2 mL/min时,金、铂、钯的富集效果最佳,回收率接近100%.经对共存离子影响的校正,用电感耦合等离子体质谱法测定国家一级标准物质,其结果较认定值不超差.方法检出限为Pd 0.6 ng/mL,Pt 0.5ng/mL,Au 0.7ng/mL.随机选取5个地质样品用本法进行分析,同时与硫镍试金-ICP-MS法进行比较,结果一致.两组结果经双样本方差F检验,无显著性差异.

  13. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  14. 浊点萃取-电感耦合等离子体质谱法测定环境样品中的痕量铂钯%Determination of trace platinum and palladium in environmental samples by cloud point extraction coupled with inductively coupled plasma-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    张欣; 刘崴; 李冰; 胡俊栋

    2012-01-01

    Accurate determination of precious metals at trace levels in environmental matrices is still a difficult task because of their complex components and the possible interferences during analyzing. Cloud point extraction (CPE) is a new kind of preconcentration and separation technology which has many prominent virtues such as completely phase separation, easy to be operated, high enrichment efficiency and less harmful for environment and operators. It has been successfully used in the determination of lead, zinc, cobalt, copper and many other metals. But the study about precious metals in environmental matrices using CPE was comparatively few. So in this paper a new method for the determination of trace amounts of platinum and palladium in environmental samples using CPE coupled with ICP-MS is described. Trace amounts of Pt and Pd were extracted from the sample solutions in the form of coordination complex with 2-mercaptobenzothiazole (2-MBT) in 1 mol/L HC1 medium,using a non-ionic surfactant Triton Χ-100. The main parameters affecting extraction and determination were evaluated in detail, such as the solution acidity, the amount of 2-MBT, the concentration of Triton X-100 and SnCl2, the extraction temperature and time, as well as the interferences. Under optimized conditions, the recoveries of Pt and Pd were all above 95%. The detection limits obtained for Pt and Pd were 0. 22 ng/g and 0. 17 ng/g, respectively. CPE has an effective alleviation of interfering ions and a relatively sensitivity for separating the elements of Pt and Pd from large amount of co-existing ions which could influence the subsequent determination by ICP-MS. The method was successfully applied to the analysis of trace amounts of Pt and Pd in water, road dust and soil samples. The results showed that this method is reliable and can meet the most request of Pt and Pd determination in many environmental samples.%建立了浊点萃取-电感耦合等离子体质谱法测定环境样品

  15. Palladium-catalyzed Carbonylative Cyclization of 2-Bromocyclohex-1-enecarbalde-hydes with Aliphatic Primary Amines Leading to 3-Aminohydroisoindol-1-ones

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Yeon Kyu; Cho, Chan Sik; Yoon, Nam Sik [Kyungpook National Univ., Daegu (Korea, Republic of)

    2013-09-15

    It has been shown that 2-bromocyclohex-1-enecarbaldehydes, which are readily prepared from α-methylene containing cyclohexanones under the bromination conditions of Vilsmeier-Haak reaction, undergo carbonylative cyclization with aliphatic primary amines in the presence of a palladium catalyst and a bidentate phosphorus ligand to give 3-aminohydroisoindol-1-ones. The present reaction provides a promising route for the synthesis of valuable heterocycles from readily available starting ketones. Further study of synthetic applications to heterocycles using these ketones is currently under investigation. Palladium-catalyzed carbonylation of organic halides (or triflates) followed by intramolecular cyclization (carbonyl-ative cyclization) has been widely explored and used as a promising synthetic tool for the construction of the structural core of many pharmacologically and biologically active lactones and lactams.

  16. Toxicity of platinum compounds.

    Science.gov (United States)

    Hartmann, Jörg Thomas; Lipp, Hans-Peter

    2003-06-01

    Since the introduction of platinum-based combination chemotherapy, particularly cisplatin, the outcome of the treatment of many solid tumours has changed. The leading platinum compounds in cancer chemotherapy are cisplatin, carboplatin and oxaliplatin. They share some structural similarities; however, there are marked differences between them in therapeutic use, pharmacokinetics and adverse effects profiles [1-4]. Compared to cisplatin, carboplatin has inferior efficacy in germ-cell tumour, head and neck cancer and bladder and oesophageal carcinoma, whereas both drugs seem to have comparable efficacy in advanced non-small cell and small cell lung cancer as well as ovarian cancer [5-7]. Oxaliplatin belongs to the group of diaminocyclohexane platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid [8,9]. Other platinum compounds such as oral JM216, ZD0473, BBR3464 and SPI-77, which is a pegylated liposomal formulation of cisplatin, are still under investigation [10-13], whereas nedaplatin has been approved in Japan for the treatment of non-small cell lung cancer and other solid tumours. This review focuses on cisplatin, carboplatin and oxaliplatin.

  17. Development of radioactive platinum group metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.S.; Kim, Y.S.; Kim, Y.E. [and others

    1999-03-01

    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metals such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solutions was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400m{sup 2}/g.The content of palladium impregnated on the support was 1 to 10 wt. %. Hydrogen isotope exchange efficiency of more than 93% to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its activity is unimportant as in nuclear industries. (author). 86 refs., 44 tabs., 88 figs.

  18. Development of radioactive platinum group metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.S.; Kim, Y.S.; Kim, Y.E. [and others

    1999-03-01

    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metals such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solutions was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400m{sup 2}/g.The content of palladium impregnated on the support was 1 to 10 wt. %. Hydrogen isotope exchange efficiency of more than 93% to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its activity is unimportant as in nuclear industries. (author). 86 refs., 44 tabs., 88 figs.

  19. Recovery of palladium from a spent automobile catalyst leaching solution by a thiodiglycolamide derivative

    OpenAIRE

    2015-01-01

    In the sequence of previous research on the development of novel liquid-liquid amidetype compounds to efficiently and selectively extract platinum-group metals (PGMs) from concentrated hydrochloric acid media, a specific thiodiglycolamide derivative – N,N’-dimethyl-N,N’-dicyclohexylthiodiglycolamide (DMDCHTDGA) – has been applied for the recovery of palladium(II) from a spent automobile catalyst leaching solution, containing palladium(II) and rhodium(III) as PGMs. The results obtained are rat...

  20. Ozone Sensing Based on Palladium Decorated Carbon Nanotubes

    OpenAIRE

    2014-01-01

    Multiwall carbon nanotubes (MWCNTs) were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd) deposited by drop coating on platinum interdigitated electrodes on a SiO2 substrate. The sensor exhibited a resistance change to ozone (O3) with a response time of 60 s at different temperatures and the capability of detecting conc...

  1. 浊点萃取-电感耦合等离子体质谱法测定植物样品中的痕量铂与钯%Determination of trace platinum and palladium in plant samples by cloud point extraction coupled with inductively coupled plasma-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    刘崴; 张欣; 李冰; 胡俊栋; 杨红霞; 黄中起

    2013-01-01

    建立了浊点萃取电感耦合等离子体质谱法测定植物样品中痕量铂与钯的方法,方法检出限分别为0.17 ng/g和0.10 ng/g,样品加标回收率在85%~110%之间.利用建立的方法对采自北京环路旁的植物样品进行了测定,铂与钯含量范围分别为0.35 ~5.35 ng/g和1.95~10.85 ng/g,钯的含量普遍高于铂的含量.%A method for the determination of trace amounts of platinum and palladium in plant samples using cloud point extraction ( CPE) coupled with inductively coupled plasma mass spectrometry ( ICP-MS) is described. The method detection limits for Pt and Pd were 0. 17 ng/g and 0. 10 ng/g, respectively. The standard recoveries were 85% ~110%. The method was successfully applied to the analysis of amounts of Pt and Pd in plant samples collected from the sides of the main ring roads in Beijing. The results indicated that the content ranges of Pt and Pd were 0. 35 ~5. 35 ng/g and 1. 95 ~10. 85 ng/g, respectively, and the content of Pd was more than Pt content generally.

  2. Platinum impact assessment

    OpenAIRE

    Yip, Joyce Pui Yan

    2007-01-01

    This paper presents a comprehensive strategic analysis of Company X's strategies to mitigate its risks from volatile platinum prices, since Platinum is a critical component of fuel cells. It is recommended that Company X consider leasing platinum to lower cash flow requirements to meet its platinum demand over the next 5 years. A shorter platinum leasing period will reduce Company X's platinum market risk. OEMs can set up metal accounts with catalyst suppliers to eliminate Company X from plat...

  3. The influence of ethylenediamine tetra acetic acid (EDTA) on the transformation and solubility of metallic palladium and palladium(II) oxide in the environment.

    Science.gov (United States)

    Zereini, Fathi; Wiseman, Clare L S; Vang, My; Albers, Peter; Schneider, Wolfgang; Schindl, Roland; Leopold, Kerstin

    2015-05-01

    The environmental occurrence of elevated concentrations of platinum (Pt), palladium (Pd) and rhodium (Rh) from automotive catalytic converters has been well-documented. Limited information exists regarding their chemical behavior post-emission, however, especially in the presence of commonly occurring complexing agents. The purpose of this study is to examine the influence of ethylenediamine tetra acetic acid (EDTA) on the possible environmental transformation and solubility of Pd by conducting batch experiments using metallic palladium (Pd black) and palladium(ii) oxide (PdO). Changes in the particle surface chemistry of treated samples were analyzed using X-ray Photoelectron Spectroscopy (XPS) and Transition Electron Microscopy/Energy Dispersive X-ray Spectrometry (TEM/EDX) techniques. Metallic palladium was partially transformed into PdOx (x environmental immobility of Pd, small amounts of this element emitted in metallic form are likely to be soluble in the presence of complexing agents such as EDTA.

  4. New transition metal-rich rare-earth palladium/platinum aluminides with RET{sub 5}Al{sub 2} composition. Structure, magnetism and {sup 27}Al NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Benndorf, Christopher [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Stegemann, Frank; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie

    2015-06-01

    REPd{sub 5}Al{sub 2} compounds with RE = Ce-Gd as well as Y and Lu have been previously synthesized. Although some compounds with the small lanthanides also exist, the compounds with intermediate-sized rare-earth elements (RE = Tb-Yb) had not been prepared. We report on the missing members of the REPd{sub 5}Al{sub 2} (RE = Tb-Yb) series as well as on the new REPt{sub 5}Al{sub 2} (RE = Y, Gd-Tm, Lu) series, which we have synthesized and structurally as well as magnetically characterized. All members crystallize isostructurally in the ZrNi{sub 2}Al{sub 5} type with an anti-arrangement of the T = Pd/Pt and Al atoms. YPd{sub 5}Al{sub 2} and LuPd{sub 5}Al{sub 2}, as well as the respective platinum homologs, YPt{sub 5}Al{sub 2} and LuPt{sub 5}Al{sub 2}, have been characterized also by {sup 27}Al magic-angle spinning nuclear magnetic resonance spectroscopy. Consistent with the XRD analysis, the spectra indicate the existence of only one distinct Al site in the structure.

  5. Production of Nanopowders of Platinum Metals Using the Chemical Reduction Method

    Institute of Scientific and Technical Information of China (English)

    PYATAKHINA E. S.; BUSLAYEVA T. M.; VOLCHKOVA E. V.; KHRISTICH E. A.; SERGEYEVA T. Yu.

    2012-01-01

    The literary data on the application of various methods for the production of nanopowders of platinum metals and alloys have been summarized,and the selection of the method of chemical reduction from salt solutions has been substantiated as the simplest and most affordable.The optimum conditions for the production of nanoparticles of metal palladium and platinum/cobalt alloy,using the effect of boranes with various structures,have been selected.

  6. Experimental investigations of the hydrothermal geochemistry of platinum and palladium: IV. The stoichiometry of Pt(IV) and Pd(II) chloride complexes at 100 to 300°C

    Science.gov (United States)

    Gammons, C. H.

    1995-05-01

    A technique based on the common ion effect was used to obtain information on the stoichiometry of the Pt(IV) and Pd(II) chloride complexes at elevated temperature. The solubility of AgCl(s) was measured in solutions of fixed mHCl and varying ΣPt(IV) or ΣPd(II) concentration. Parallel experiments were conducted at Me/Cl mole ratios (Me = Pt or Pd) of 0.0-0.5 for mHCl = 0.03-3.0, at T = 100, 200, and 300°C. The average Cl ligand numbers for Pt ranged from 4.2 to 5.8, with the majority of values > 5. These results are adequately explained by a mixture of the simple monomeric species PtCl 62t-, PtCl 5-, and PtCl 40. The temperature dependence of the equilibrium constant for the dissociation reaction PtCl 62- = PtCl 5- + Cl - was obtained: log K = 2.40(±0.25) - 1278/ T, K (valid to 573 K), which is in good agreement with published low temperature data. The neutral PtCl 40 species may become important at 300°C and low chloride concentrations (0.016 m HCl). Extrapolation of existing data indicates that the Pt(IV) chloride complexes are stable with respect to Pt(II) chloride complexes over a range of ƒO 2-pH conditions which narrows quickly with increase in temperature. Nonetheless, PtCl 62- may be the dominant form of dissolved Pt in highly oxidized brines to at least 100°C. The average Cl ligand numbers for palladium ranged from 2.164 to 2.83, and were insensitive to temperature. These results could be explained by a mixture of PdCl 2 and PdCl 3-. However, this is in disagreement with published experimental data which indicate that PdCl 4-2 is the predominant form of aqueous Pd at high chloride concentrations. An alternate explanation is that a significant quantity of the total aqueous Pd was present as polynuclear complexes, due to the very high Pd/Cl ratios of the experiments. Insufficient data exist to discriminate between these two hypotheses.

  7. Examining the surfaces in used platinum catalysts

    Directory of Open Access Journals (Sweden)

    Trumić B.

    2009-01-01

    Full Text Available For the purpose of finding more advanced platinum catalyst manufacturing technologies and achieving a higher degree of ammonia oxidation, metallographic characterization has been done on the surface of catalyst gauzes and catalyst gripper gauzes made from platinum and palladium alloys. For the examined samples of gauzes as well as the cross section of the wires, a chemical analysis was provided. The purpose of this paper is the metallographic characterization of examined alloys carried out by way of electronic microscopic scanning, X-rays as well as chemical assays which contributed greatly to a better understanding of the surface deactivation, in other words a better consideration of structural changes occurring on the wire surface.

  8. Facet effects of palladium nanocrystals for oxygen reduction in ionic liquids and for sensing applications

    Science.gov (United States)

    Tang, Yongan; Chi, Xiaowei; Zou, Shouzhong; Zeng, Xiangqun

    2016-03-01

    Palladium nanocrystals enclosed by {100} and {110} crystal facets, were successfully synthesized through an aqueous one-pot synthesis method. A new thermal annealing approach was developed for fabricating these palladium nanocrystals as a working electrode on a gas permeable membrane to study the facet effects of the oxygen reduction process in an ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpy][NTf2]). Results were compared with the same processes at a conventional platinum electrode. Our study shows that the structural difference between the two facets of Pd nanocrystals has little effect on the oxygen reduction process but significantly affects the oxidation process of the superoxide. It is found that the Pd{110}/IL interface can better stabilize superoxide radicals revealed by a more positive oxidation potential compared to that of Pd{100}. In addition, the analytical characteristic of utilizing both palladium nanocrystals as electrodes for oxygen sensing is comparable with a polycrystal platinum oxygen sensor, in which Pd{110} presents the best sensitivity and lowest detection limit. Our results demonstrate the facet-dependence of oxygen reduction in an ionic liquid medium and provide the fundamental information needed to guide the applications of palladium nanocrystals in electrochemical gas sensor and fuel cell research.Palladium nanocrystals enclosed by {100} and {110} crystal facets, were successfully synthesized through an aqueous one-pot synthesis method. A new thermal annealing approach was developed for fabricating these palladium nanocrystals as a working electrode on a gas permeable membrane to study the facet effects of the oxygen reduction process in an ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpy][NTf2]). Results were compared with the same processes at a conventional platinum electrode. Our study shows that the structural difference between the two facets of Pd

  9. Sensitization to palladium in Europe

    NARCIS (Netherlands)

    Muris, J.; Goossens, A.; Gonçalo, M.; Bircher, A.J.; Giménez-Arnau, A.; Foti, C.; Bruze, M.; Andersen, K.E.; Rustemeyer, T.; Feilzer, A.J.; Kleverlaan, C.J.

    2015-01-01

    Background Recently, sodium tetrachloropalladate (Na2PdCl4) was found to be a more sensitive palladium patch test allergen than palladium dichloride (PdCl2). Objectives To determine the optimal test concentration of Na2PdCl4, to evaluate the prevalence of palladium sensitization with Na2PdCl4 and Pd

  10. [Platinum compounds: metabolism, toxicity and supportive strategies].

    Science.gov (United States)

    Lipp, H P; Hartmann, J T

    2005-02-09

    Although the leading platinum compounds, cisplatin, carboplatin, and oxaliplatin, share some structural similarities, there are marked differences between them in therapeutic uses, pharmacokinetics, and adverse effects profiles. Compared with cisplatin, carboplatin has inferior efficacy in germ-cell tumors, head and neck cancers, and bladder and esophageal carcinomas, whereas the two drugs appear to have comparable efficacy in ovarian cancer, extensive small-cell lung cancers (SCLC), and advanced non-small-cell lung cancers (NSCLC). Oxaliplatin belongs to the group of diaminocyclohexane (DACH) platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid. Nedaplatin has been registered in Japan, whereas other derivatives, like JM216 (which is the only orally available platinum derivative), ZD0473, BBR3464, and SPI-77 (a liposomal formulation of cisplatin), are still under investigation. The adverse effects of platinum compounds are reviewed together with possible prevention strategies.

  11. High plasma exposure to pemetrexed leads to severe hyponatremia in patients with advanced non small cell lung cancer receiving pemetrexed-platinum doublet chemotherapy

    Directory of Open Access Journals (Sweden)

    Gota V

    2014-06-01

    Full Text Available Vikram Gota,1 Krunal Kavathiya,1 Kartik Doshi,1 Murari Gurjar,1 Solai E Damodaran,1 Vanita Noronha,2 Amit Joshi,2 Kumar Prabhash2 1Department of Clinical Pharmacology, Advanced Centre for Treatment Research and Education in Cancer, 2Department of Medical Oncology, Tata Memorial Hospital, Mumbai, India Background: Pemetrexed-platinum doublet therapy is a standard treatment for stage IIIb/IV nonsquamous non small cell lung cancer (NSCLC. While the regimen is associated with several grade ≥3 toxicities, hyponatremia is not a commonly reported adverse effect. Here we report an unusually high incidence of grade ≥3 hyponatremia in Indian patients receiving pemetrexed-platinum doublet, and the pharmacological basis for this phenomenon. Methods: Forty-six patients with advanced NSCLC were enrolled for a bioequivalence study of two pemetrexed formulations. All patients received the pemetrexed-platinum doublet for six cycles followed by single-agent pemetrexed maintenance until progression. Pharmacokinetic blood samples were collected at predefined time points during the first cycle and the concentration-time profile of pemetrexed was investigated by noncompartmental analysis. Hyponatremic episodes were investigated with serum electrolytes, serum osmolality, urinary sodium, and urine osmolality. Results: Sixteen of 46 patients (35% had at least one episode of grade ≥3 hyponatremia. Twenty-four episodes of grade ≥3 hyponatremia were observed in 200 cycles of doublet chemotherapy. Plasma exposure to pemetrexed was significantly higher in patients with high-grade hyponatremia than in those with low-grade or no hyponatremia (P=0.063 and P=0.001, respectively. Pemetrexed clearance in high-grade hyponatremia was quite low compared with normal and low-grade hyponatremia (P=0.001 and P=0.055, respectively. Median pemetrexed exposure in this cohort was much higher than that reported in the literature from Western studies. Conclusion: Higher exposure to

  12. Platinum group metal recovery and catalyst manufacturing process

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. S.; Kim, Y. S.; Yoo, J. H.; Lee, H. S.; Ahn, D. H.; Kim, K. R.; Lee, S. H.; Paek, S. W.; Kang, H. S.

    1998-03-01

    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metal such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solution was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400 m{sup 2}/g. The content of palladium impregnated on the support was 10 wt.%. Hydrogen isotope exchange efficiency of 93 % to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its actively is unimportant as in nuclear industries. (author). 63 refs., 38 tabs., 36 figs.

  13. Silver-palladium cathode

    Energy Technology Data Exchange (ETDEWEB)

    Poizot, Philippe [Laboratoire de Reactivite et Chimie des Solides, UMR CNRS 6007, Universite de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cedex (France); Simonet, Jacques, E-mail: jacques.simonet@univ-rennes1.f [Laboratoire MaCSE, UMR CNRS 6226, Universite de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France)

    2010-12-15

    The formation of silver-palladium electrodes is described. It mainly corresponds to the palladization of silver by means of treatment with palladium salts (nitrate and sulphate) in acidic media. Other ways may exist such as the modification of solid conductors like carbons by deposition of a silver-palladium alloy. By using those electrodes in polar aprotic solvents, the one-electron cleavage of carbon-halogen bonds of most alkyl iodides and bromides may yield free alkyl radicals. Coupling and cross-coupling reactions can easily be carried out at such electrodes. The present review aims at discussing the electro-catalytic process as well as providing an update on the state of the art on this new mode of scission regarding carbon-heteroatom bonds.

  14. Novel Base Metal-Palladium Catalytic Diesel Filter Coating with NO2 Reducing Properties

    DEFF Research Database (Denmark)

    Johansen, K.; Dahl, S.; Mogensen, G.

    2007-01-01

    A novel alternative base metal/palladium coat has been developed that has limited NO2 formation and which even removes NO2 in a wide temperature range.Soot combustion, HC conversion and CO conversion properties are comparable to current platinum based solutions but the coating has a more attractive...... price structure. The novel base metal/palladium catalytic coat has been applied on commercial silicon carbide wall flow diesel filters and tested in an engine test bench. Results from engine bench tests concerning soot combustion, HC-, CO-, NO2- removal with the novel coat will are compared to present...

  15. PLATINUM AND FUEL CELLS

    Science.gov (United States)

    Platinum requirements for fuel cell vehicles (FCVS) have been identified as a concern and possible problem with FCV market penetration. Platinum is a necessary component of the electrodes of fuel cell engines that power the vehicles. The platinum is deposited on porous electrodes...

  16. Aptamer selection for fishing of palladium ion using graphene oxide-adsorbed nanoparticles.

    Science.gov (United States)

    Cho, Yea Seul; Lee, Eun Jeong; Lee, Gwan-Ho; Hah, Sang Soo

    2015-12-01

    A new aptamer selection method using graphene oxide (GO)-adsorbed nanoparticles (GO-adsorbed NPs) was employed for specific fishing of palladium ion. High affinity ssDNA aptamers were isolated through 13 rounds of selection and the capacity of the selected DNA aptamers for palladium ion uptake was measured, clarifying that DNA01 exhibits the highest affinity to palladium ion with a dissociation constant (Kd) of 4.60±1.17 μM. In addition, binding ability of DNA01 to palladium ion was verified against other metal ions, such as Li(+), Cs(+), Mg(2+), and Pt(2+). Results of the present study suggest that future modification of DNA01 may improve palladium ion-binding ability, leading to economic recovery of palladium from water solution.

  17. Ozone sensing based on palladium decorated carbon nanotubes.

    Science.gov (United States)

    Colindres, Selene Capula; Aguir, Khalifa; Cervantes Sodi, Felipe; Vargas, Luis Villa; Salazar, José Moncayo; Febles, Vicente Garibay

    2014-04-14

    Multiwall carbon nanotubes (MWCNTs) were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd) deposited by drop coating on platinum interdigitated electrodes on a SiO₂ substrate. The sensor exhibited a resistance change to ozone (O₃) with a response time of 60 s at different temperatures and the capability of detecting concentrations up to 20 ppb. The sensor shows the best response when exposed to O3 at 120 °C. The device shows a very reproducible sensor performance, with high repeatability, full recovery and efficient response.

  18. Comparative analysis of high temperature strength of platinum and its binary alloys with low content of alloying element

    Directory of Open Access Journals (Sweden)

    Stanković Draško S.

    2012-01-01

    Full Text Available The comparative analysis of platinum and its binary alloys (containing alloying elements up to 10 mass% mechanical properties at high temperatures has been carried out. The goal of the analysis was to investigate new application possibilities for products based on platinum and platinum alloys, and to expand the existing database of platinum metals, originating from the RTB group, Serbia. Palladium, rhodium, ruthenium, iridium and gold were used as alloying elements. In order to examine the effect of alloying elements’ low concentrations on the high-temperature platinum durability, creep rate, rupture time, tensile strength and relative elongation at high temperatures, up to 1400 °C, were determined. In addition, changes in the structure of dislocations were tracked. The summary of investigation results led to conclusion that, of all the alloying elements used, the best influence on high-temperature platinum durability has rhodium.

  19. Mechanism of Platinum Derivatives Induced Kidney Injury

    Directory of Open Access Journals (Sweden)

    Feifei YAN

    2015-09-01

    Full Text Available Platinum derivatives are the most widely used chemotherapeutic agents to treat solid tumors including ovarian, head and neck, and testicular germ cell tumors, lung cancer, and colorectal cancer. Two major problems exist, however, in the clinic use of platinum derivatives. One is the development of tumor resistance to the drug during therapy, leading to treatment failure. The other is the drug’s toxicity such as the cisplatin’s nephrotoxicity, which limits the dose that can be administered. This paper describes the mechanism of platinum derivatives induced kidney injury.

  20. Lead

    Science.gov (United States)

    ... found? Who is at risk? What are the health effects of lead? Get educational material about lead Get certified as a Lead Abatement Worker, or other abatement discipline Lead in drinking water Lead air pollution Test your child Check and maintain your home ...

  1. Innovative Use of Palladium Compounds to Selectively Detect Live Enterobacteriaceae Cells in Milk by Polymerase Chain Reaction.

    Science.gov (United States)

    Soejima, Takashi; Iwatsuki, Kei-Ji

    2016-09-23

    Ethidium- and propidium-monoazide (EMA and PMA) have been used in combination with PCR for more than a decade to facilitate the discrimination of live and dead bacteria (LD discrimination). These methods, however, require many laborious procedures, including the use of a darkroom. Here, we demonstrate an innovative use of palladium compounds involving lower limits of detection and quantification of targeted live cells, fewer laborious procedures, lower costs, and potentially higher throughput analysis than the use of EMA and PMA. We have also recently reported platinum compounds for LD discrimination, but platinum compounds carry 3 times higher costs because of the requirement for much larger amounts for LD discrimination than palladium compounds. Palladium compounds can penetrate dead (compromised) but not live bacteria and can be chelated primarily by chromosomal DNA and cell wall transmembrane proteins, with small amounts of DNA-binding proteins in vivo The new mechanism for palladium compounds is obviously different from that of platinum compounds which primarily target DNA. Combining palladium compounds with PCR in water resulted in much clearer discrimination between live and dead Enterobacteriaceae bacteria compared with the PMA method. Palladium-PCR correlated with reference plating or with the currently used PMA-PCR method for pasteurized milk, based on EN ISO 16140:2003 validation. Palladium-PCR enabled us to specifically detect and assay viable Enterobacteriaceae cells at concentrations of 5 to 10 CFU/ml in milk following USA/EU regulations after a 4.5-h process in a typical laboratory exposed to natural/electric light, as specified by USA/EU regulations.

  2. Global exploration and production capacity for platinum-group metals from 1995 through 2015

    Science.gov (United States)

    Wilburn, David R.

    2012-01-01

    Platinum-group metals (PGMs) are required in a variety of commercial, industrial, and military applications for many existing and emerging technologies, yet the United States is highly dependent on foreign sources of PGMs. Information on global exploration for PGMs since 1995 has been used in this study as a basis for identifying locations where the industry has determined that exploration has provided data sufficient to warrant development of a new mine or expansion of an existing operation or where a significant increase in capacity for PGMs is anticipated by 2015. Discussions include an overview of the industry and the selected sites, factors affecting mineral supply, and circumstances leading to the development of mineral properties with the potential to affect mineral supply. Of the 52 sites or regional operations that were considered in this analysis, 16 sites were producing before 1995, 28 sites commenced production from 1995 through 2010, and 8 sites were expected to begin production from 2011 through 2015 if development plans came to fruition. The United States imports PGMs primarily from Canada, Russia, South Africa, and Zimbabwe to meet increasing demand for these materials in a variety of specialized and high-tech applications. Feed sources of PGMs are changing in South Africa and Russia, which together accounted for about 89 percent of platinum production and 82 percent of palladium production in 2009. A greater amount of South African PGM capacity is likely to come from deeper, higher cost Upper Group Reef seam 2 deposits and deposits in the Eastern Bushveld area. Future Russian PGM capacity is likely to come from ore zones with generally lower PGM content and different platinum-to-palladium ratios than the nickel-rich ore that dominated PGM supply in the 1990s. Because PGM supply from Canada and Russia is derived as a byproduct of copper and nickel mining, the PGM supply from these countries is influenced by economic, environmental, political, and

  3. Global exploration and production capacity for platinum-group metals from 1995 through 2015

    Science.gov (United States)

    Wilburn, David R.

    2012-01-01

    Platinum-group metals (PGMs) are required in a variety of commercial, industrial, and military applications for many existing and emerging technologies, yet the United States is highly dependent on foreign sources of PGMs. Information on global exploration for PGMs since 1995 has been used in this study as a basis for identifying locations where the industry has determined that exploration has provided data sufficient to warrant development of a new mine or expansion of an existing operation or where a significant increase in capacity for PGMs is anticipated by 2015. Discussions include an overview of the industry and the selected sites, factors affecting mineral supply, and circumstances leading to the development of mineral properties with the potential to affect mineral supply. Of the 52 sites or regional operations that were considered in this analysis, 16 sites were producing before 1995, 28 sites commenced production from 1995 through 2010, and 8 sites were expected to begin production from 2011 through 2015 if development plans came to fruition. The United States imports PGMs primarily from Canada, Russia, South Africa, and Zimbabwe to meet increasing demand for these materials in a variety of specialized and high-tech applications. Feed sources of PGMs are changing in South Africa and Russia, which together accounted for about 89 percent of platinum production and 82 percent of palladium production in 2009. A greater amount of South African PGM capacity is likely to come from deeper, higher cost Upper Group Reef seam 2 deposits and deposits in the Eastern Bushveld area. Future Russian PGM capacity is likely to come from ore zones with generally lower PGM content and different platinum-to-palladium ratios than the nickel-rich ore that dominated PGM supply in the 1990s. Because PGM supply from Canada and Russia is derived as a byproduct of copper and nickel mining, the PGM supply from these countries is influenced by economic, environmental, political, and

  4. Stabilizing platinum in phosphoric acid fuel cells

    Science.gov (United States)

    Remick, R. J.

    1982-01-01

    Platinum sintering on phosphoric acid fuel cell cathodes is discussed. The cathode of the phosphoric acid fuel cell uses a high surface area platinum catalyst dispersed on a conductive carbon support to minimize both cathode polarization and fabrication costs. During operation, however, the active surface area of these electrodes decreases, which in turn leads to decreased cell performance. This loss of active surface area is a major factor in the degradation of fuel cell performance over time.

  5. Effect of precursor nature on the performance of palladium-cobalt electrocatalysts for direct methanol fuel cells

    Science.gov (United States)

    Serov, Alexey; Nedoseykina, Tatyana; Shvachko, Oleg; Kwak, Chan

    The performance of platinum-free palladium-cobalt catalysts in oxygen reduction was investigated for a direct methanol fuel cell. The dependence of catalytic activity on precursor nature was determined for two classes of precursors; namely, palladium chloride and palladium nitrate. The nitrate precursor exhibits much higher catalytic performance than the chloride precursor. X-ray absorption fine structure (XAFS) spectra indicate that the structure of palladium catalyst prepared from nitrate is much closer to Pd 3Co structure that can explain high catalytic activity. The MEA prepared from the nitrate catalyst achieved the peak power density of 125 mW cm -2, which is much higher than 19 mW cm -2 measured on the cell prepared from the chloride catalyst.

  6. Effect of Rotation Rate on the Formation of Platinum-modified Polyaniline Film and Electrocatalytic Oxidation of Methanol

    Institute of Scientific and Technical Information of China (English)

    Qiu Hong LI; Lin NIU; Chang Qiao ZHANG; Feng Hua WEI; Hu ZHANG

    2004-01-01

    The oxidation of methanol was investigated on platinum-modified polyaniline electrode. Changes in the electrode rotation rates (Ω) during platinum electrodeposition remarkably affect the formation and distribution of platinum in the polymer matrix and consequently lead to different currents of methanol oxidation. The results show that platinum loading is proportional to rotation ratesΩ1/2.

  7. A dual-emissive ionic liquid based on an anionic platinum(II) complex

    OpenAIRE

    Ogawa, Tomohiro; Yoshida, Masaki; Ohara, Hiroki; Kobayashia, Atsushi; Kato, Masako

    2015-01-01

    An ionic liquid fabricated froman anionic cyclometalated platinum(II) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.

  8. A dual-emissive ionic liquid based on an anionic platinum(ii) complex.

    Science.gov (United States)

    Ogawa, Tomohiro; Yoshida, Masaki; Ohara, Hiroki; Kobayashi, Atsushi; Kato, Masako

    2015-09-07

    An ionic liquid fabricated from an anionic cyclometalated platinum(ii) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.

  9. Platinum and palladium alloys suitable as fuel cell electrodes

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention concerns electrode catalysts used in fuel cells, such as proton exchange membrane (PEM) fuel cells. The invention is related to the reduction of the noble metal content and the improvement of the catalytic efficiency by low level substitution of the noble metal to provide new...

  10. Platinum and palladium alloys suitable as fuel cell electrodes

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention concerns electrode catalysts used in fuel cells, such as proton exchange membrane (PEM) fuel cells. The invention is related to the reduction of the noble metal content and the improvement of the catalytic5 efficiency by low level substitution of the noble metal to provide new...

  11. Platinum and Palladium Alloys Suitable as Fuel Cell Electrodes

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention concerns electrode catalysts used in fuel cells, such as proton exchange membrane (PEM) fuel cells. The invention is related to the reduction of the noble metal content and the improvement of the catalytic efficiency by low level substitution of the noble metal to provide new...

  12. Hydrogenation of cottonseed oil with nickel, palladium and platinum catalysts

    Science.gov (United States)

    A number of commercial catalysts have been used to study hydrogenation of cottonseed oil, with the goal of minimizing trans fatty acid (TFA) content. Despite the different temperatures used, catalyst levels, and reaction times, the data from each catalyst type fall on the same curve when the TFA le...

  13. The electroanalytical detection of hydrazine: a comparison of the use of palladium nanoparticles supported on boron-doped diamond and palladium plated BDD microdisc array.

    Science.gov (United States)

    Batchelor-McAuley, Christopher; Banks, Craig E; Simm, Andrew O; Jones, Timothy G J; Compton, Richard G

    2006-01-01

    We show that both a random distribution of palladium nanoparticles supported on a BDD electrode or a palladium plated BDD microelectrode array can each provide a sensing platform for the electrocatalytic detection of hydrazine. The palladium nanoparticle modified electrode displays a sensitivity and limit of detection of 60 mA mol(-1) L and 2.6 microM respectively while the array has a sensitivity of 8 mA mol(-1) L with a detection limit of 1.8 microM. The beneficial cost implications of using palladium nano- or micro-particles in sensors compared to a palladium macroelectrode are evident. Interestingly the array of the nanoparticles shows similar sensitivity and limit of detection to the microelectrode array which probably indicates that the random distribution of the former leads to 'clumps' of nanoparticles that effectively act as microelectrodes.

  14. Single palladium nanowire growth in place assisted by dielectrophoresis and focused ion beam.

    Science.gov (United States)

    La Ferrara, Vera; Alfano, Brigida; Massera, Ettore; Di Francia, Girolamo

    2009-05-01

    Here we report, for the first time, on the combined use of Focused Ion Beam and Dielectrophoresis techniques for the fabrication of a nanodevice whose operating mechanism relies on a single palladium nanowire. Focused Ion Beam is used to deposit, without photolithographic masks, platinum microelectrodes on a silicon/silicon nitride substrate. Dielectrophoresis is employed for assembling the palladium nanowire, starting from a saturated palladium particles solution, and precisely positioning it between the nanocontacts. The nanodevice works as a hydrogen sensor, confirming the reliability of technology. Its electrical response has been recorded, at room temperature, in a dynamic environment, where different hydrogen concentrations, from 0.1% to 4% in dry air, have been introduced. Its sensitivity, towards 0.1% to 1% gas concentrations in dry air, has been calculated, too.

  15. Novel Base Metal-Palladium Catalytic Diesel Filter Coating with NO2 Reducing Properties

    DEFF Research Database (Denmark)

    Johansen, K.; Dahl, S.; Mogensen, G.

    2007-01-01

    A novel alternative base metal/palladium coat has been developed that has limited NO2 formation and which even removes NO2 in a wide temperature range.Soot combustion, HC conversion and CO conversion properties are comparable to current platinum based solutions but the coating has a more attracti...... solutions. Furthermore, durability results from base metal/Pd coated DPFs installed on operating taxis and related tests cycle data is given....

  16. Uptake of platinum by zebrafish (Danio rerio) and ramshorn snail (Marisa cornuarietis) and resulting effects on early embryogenesis.

    Science.gov (United States)

    Osterauer, Raphaela; Haus, Nadine; Sures, Bernd; Köhler, Heinz-R

    2009-11-01

    Platinum group elements (PGEs), platinum, palladium and rhodium are widely used in automobile catalytic converters. PGEs are emitted into the environment and enter the aquatic ecosystem via runoff rainwater. The present study investigated the bioavailability of platinum chloride for the zebrafish (Danio rerio) and the ramshorn snail (Marisa cornuarietis) and determined the bioaccumulation rate of platinum. Applying the fish early life stage assay for D. rerio (DarT) and the Marisa embryo toxicity test ("Mariett") for M. cornuarietis, effects of platinum chloride on the embryonic development were investigated. Platinum concentrations tested in this study ranged from environmentally relevant concentrations of 38 ng L(-1) up to a concentration of 74.2 microg L(-1) for D. rerio and of 200 ngL(-1) up to 98.7 microg L(-1) for M. cornuarietis. Platinum was found to be accumulated in both organisms. Bioaccumulation factors (BAFs) were in the range of 5-55 for D. rerio and of 218.4-723.9 for M. cornuarietis, depending on the tested Pt concentrations. During the embryonic development, platinum was shown to alter the heart rate of both organisms already at the lowest tested concentration. At higher concentrations, platinum decelerated the hatching rate of the embryos of both species. Additionally, a retardation of the general development and a loss of weight due to platinum exposure was observed in M. cornuarietis. Results of this study contribute important data on the ecotoxicity of a rarely studied element.

  17. 2-Methoxycycloocta-1,5-dienyl platinum complexes as precursors for platinum nanoparticles

    Indian Academy of Sciences (India)

    Ninad Ghavale; Sandip Dey; Vimal K Jain; R Tewari

    2009-02-01

    Thermolysis of [Pt2 (-OR)2 (C8H12OMe)2] (R = Me or Ac) in hexadecylamine (HDA) at 210°C under argon atmosphere gave platinum nanoparticles which were characterized by XRD, EDAX and TEM analysis. Both spherical (∼ 10 nm) and rod-like (∼ 19 nm length with aspect ratio of 2.3) face centred cubic (fcc) platinum metal nanoparticles could be isolated. The thermogravimetric analyses of these complexes revealed that they undergo a single step decomposition leading to the formation of platinum metal powder.

  18. Lead

    Science.gov (United States)

    ... Chapter 6 Chapter 7 Chapter 8 Chapter 9 Appendix I Appendix II Tables Figures State Programs Alabama Alaska Arizona ... Tool Kit Resources Healthy Homes and Lead Poisoning Prevention Training Center (HHLPPTC) Training Tracks File Formats Help: ...

  19. Hydrogen absorption induced metal deposition on palladium and palladium-alloy particles

    Science.gov (United States)

    Wang, Jia X.; Adzic, Radoslav R.

    2009-03-24

    The present invention relates to methods for producing metal-coated palladium or palladium-alloy particles. The method includes contacting hydrogen-absorbed palladium or palladium-alloy particles with one or more metal salts to produce a sub-monoatomic or monoatomic metal- or metal-alloy coating on the surface of the hydrogen-absorbed palladium or palladium-alloy particles. The invention also relates to methods for producing catalysts and methods for producing electrical energy using the metal-coated palladium or palladium-alloy particles of the present invention.

  20. Behind platinum's sparkle.

    Science.gov (United States)

    Yam, Vivian W W

    2010-09-01

    As a rare and precious metal that is also resistant to wear and tarnish, platinum is known to be particularly well-suited to jewellery. Vivian Yam reflects on how, beyond its prestigious image, platinum has also found its way into a variety of fields ranging from the petrochemical to the pharmaceutical industry.

  1. Effects of nanosized metallic palladium loading and calcination on characteristics of composite silica

    Institute of Scientific and Technical Information of China (English)

    吴玉程; 吴侠; 李广海; 张立德

    2003-01-01

    In order to investigate the effects of nanosized metallic palladium loading and calcination on the characteristics of composite silica,the silica was prepared by sol-gel technique,leading to an amorphous solid with mesoporosity,and the pore size distribution is narrow,centered at 3-5 nm.The composite silica was formed by impregnating palladium precursor into the porous network with sequel calcination in hydrogen.The results show that the nanosized palladium as guest phase in the composite silica is subjected to the mesoporous structure and calcination,resulting in the changes of optical adsorption that red-shifted to higher wavelength with the palladium loading and the heating temperature.The tailoring of the optical properties can be ascribed to the effect of the nanosized metal particles and interactions occurred between palladium and silica.

  2. Combinations of concentration and strain gradient hydrogen diffusion factors in palladium alloy membranes

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, F.A. [School of Chemistry, Queen' s University Belfast, Belfast (Ireland); Bucur, R.V. [Dept. Inorganic Chemistry, University Uppsala, Uppsala (Sweden); Tong, X.Q. [Dept. of Chemistry, University of Southamton, Southampton, (United Kingdom); Sakamoto, Y. [Dept. of Mater. Science, Nagasaki University, Nagasaki (Japan); Kandasamy, K. [Dept. of Physics, University of Jaffna, Jaffna (Sri Lanka)

    1998-07-01

    Utilisations of palladium and palladium alloys as membranes for hydrogen permeation have been subjects of continuing academic and technological interest. From both standpoints, certain membranes of the palladium-platinum alloy series have been particular subjects of several studies in more recent years. Such recent series of studies have illustrated some special advantages of certain Pd-Pt alloys in providing experimental evidence of general needs of appreciation that developments of elastic strain gradients arising from lattice expansions (and contractions) produced by hydrogen entry into (and removal from) interstitial lattice sites - should be considered in combination with reliable knowledge of the pressure-composition (p-c(n)) - temperature relationships of palladium and palladium alloys in considerations of hydrogen diffusion problems. Further, in particular, a body of results, obtained with Pd{sub 81},Pt{sub 19}, and Pd{sub 77}Ag{sub 23} and Pd membranes, has also drawn attention to requirements for very serious considerations also to be given to concurrent time dependent developments of lattice strain gradients in conjunction with the hydrogen concentration gradients, in regard to estimations of hydrogen diffusion coefficients, D{sub H}, including dependencies of D{sub H} on the hydrogen contents of the membranes. 34 refs.

  3. Functional palladium tetrapod core of heterogeneous palladium-platinum nanodendrites for enhanced oxygen reduction reaction

    Science.gov (United States)

    Nguyen, Trung-Thanh; Pan, Chun-Jern; Liu, Jyong-Yue; Chou, Hung-Lung; Rick, John; Su, Wei-Nien; Hwang, Bing-Joe

    2014-04-01

    The synthesis, characterization, and application of bimetallic Pd-Pt nanocatalysts with heterogeneous structures are reported. The Pd tetrapod core is demonstrated to enhance the catalytic activity and durability of Pd@Pt nanodendrites for the oxygen reduction reaction (ORR). Special attention is given to the effects of oxalate-ion-formaldehyde during the hydrothermal synthesis of various Pd morphologies at different temperatures. Pd tetrapod synthesis can be delicately achieved without directly using hazardous CO gas. 30 wt% Pt on tetrapodal and truncated-octahedral Pd cores and 50 wt% Pt on tetrapodal Pd cores are prepared and compared against the commercial Pt/C catalyst (E-Tek) for ORR. The Pdtetrapod@30 wt% Pt catalyst exhibits the highest ORR activity. Overall, the Pd tetrapod core is a functional morphology which offers high-index facets for the subsequent deposition of Pt(110) nanodendrites, with the bimetallic interaction between two materials allowing for good electron transfer from the Pd core onto the Pt surfaces. Both effects contribute to the increased catalytic activity of Pdtetrapod@30 wt% Pt, even under a lower loading of Pt. Furthermore, Pdtetrapod@30 wt% Pt has a rather large particle size (∼39.5 nm) which enhances durability and resistance to the agglomeration of Pt.

  4. Surface characterization of silver and palladium modified glassy carbon

    Indian Academy of Sciences (India)

    Aleksandra A Perić-Grujić; Olivera M Nešković; Miomir V Veljković; Zoran V Laušević; Mila D Laušević

    2007-12-01

    In this work, the influence of silver and palladium on the surface of undoped, boron doped and phosphorus doped glassy carbon has been studied. The silver and palladium concentrations in solution, after metal deposition, were measured by atomic absorption spectrophotometer. The morphology of metal coatings was characterized by scanning electron microscopy. In order to investigate the nature and thermal stability of surface oxygen groups, temperature-programmed desorption method combined with mass spectrometric analyses, was performed. The results obtained have shown that silver and palladium spontaneously deposit from their salt solutions at the surface of glassy carbon samples. Silver deposits have dendrite structure, whilst palladium forms separate clusters. The highest amount of both silver and palladium deposits at the surface of sample containing the highest quantity of surface oxide complexes. It has been concluded that carboxyl groups and structure defects are responsible for metal reduction. Calculated desorption energies have shown that the surface modification by metal deposition leads to the formation of more stable surface of undoped and doped glassy carbon samples.

  5. Platinum hypersensitivity and desensitization.

    Science.gov (United States)

    Miyamoto, Shingo; Okada, Rika; Ando, Kazumichi

    2015-09-01

    Platinum agents are drugs used for various types of cancer. With increased frequency of administration of platinum agents, hypersensitivity reactions appear more frequently, occurring in over 25% of cases from the seventh cycle or second line onward. It then becomes difficult to conduct treatment using these agents. Various approaches have been investigated to address hypersensitivity reactions to platinum agents. Desensitization, which gradually increases the concentration of the anticancer drug considered to be the antigen until the target dosage, has been reported as being particularly effective, with a success rate of 80-100%. The aims of this paper are to present the current findings regarding hypersensitivity reactions to platinum agents and to discuss attempts of using desensitization against hypersensitivity reactions worldwide. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Heterogeneous platinum-catalyzed hydrogenation of dialkyl(diolefin)platinum(II) complexes: A new route to platinum surface alkyls

    OpenAIRE

    McCarthy, Thomas J.; Shih, Yen-Shiang; Whitesides, George M.

    1981-01-01

    Platinum metal catalyzes the reduction of dialkyl(diolefin)platinum(II) complexes by dihydrogen to alkanes and platinum(0). The reaction involves adsorption of the platinum(II) complex on the platinum(0) catalyst surface with conversion of the alkyl moieties to platinum surface alkyls; these appear as alkane products. The platinum atom originally present in the soluble organoplatinum species becomes part of the platinum(0) surface.

  7. Targeting Platinum Compounds: synthesis and biological activity

    OpenAIRE

    VAN ZUTPHEN, Steven

    2005-01-01

    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of novel (solid-phase) synthetic methods and to the discovery of several compounds with promising biological properties.

  8. Targeting Platinum Compounds : synthesis and biological activity

    NARCIS (Netherlands)

    Zutphen, Steven van

    2005-01-01

    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of

  9. Platinum-group elements in southern Africa: mineral inventory and an assessment of undiscovered mineral resources: Chapter Q in Global mineral resource assessment

    Science.gov (United States)

    Zientek, Michael L.; Causey, J. Douglas; Parks, Heather L.; Miller, Robert J.

    2014-01-01

    The platinum-group elements, platinum, palladium, rhodium, ruthenium, iridium, and osmium, possess unique physical and chemical characteristics that make them indispensable to modern technology and industry. However, mineral deposits that are the main sources of these elements occur only in three countries in the world, raising concerns about potential disruption in mineral supply. Using information in the public domain, mineral resource and reserve information has been compiled for mafic and ultramafic rocks in South Africa and Zimbabwe that host most of the world’s platinum-group element resources.

  10. Platinum-induced neurotoxicity: A review of possible mechanisms.

    Science.gov (United States)

    Kanat, Ozkan; Ertas, Hulya; Caner, Burcu

    2017-08-10

    Patients treated with platinum-based chemotherapy frequently experience neurotoxic symptoms, which may lead to premature discontinuation of therapy. Despite discontinuation of platinum drugs, these symptoms can persist over a long period of time. Cisplatin and oxaliplatin, among all platinum drugs, have significant neurotoxic potential. A distal dose-dependent symmetrical sensory neuropathy is the most common presentation of platinum neurotoxicity. DNA damage-induced apoptosis of dorsal root ganglion (DRG) neurons seems to be the principal cause of neurological symptoms. However, DRG injury alone cannot explain some unique symptoms such as cold-aggravated burning pain affecting distal extremities that is observed with oxaliplatin administration. In this article, we briefly reviewed potential mechanisms for the development of platinum drugs-associated neurological manifestations.

  11. Ozone Sensing Based on Palladium Decorated Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Selene Capula Colindres

    2014-04-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd deposited by drop coating on platinum interdigitated electrodes on a SiO2 substrate. The sensor exhibited a resistance change to ozone (O3 with a response time of 60 s at different temperatures and the capability of detecting concentrations up to 20 ppb. The sensor shows the best response when exposed to O3 at 120 °C. The device shows a very reproducible sensor performance, with high repeatability, full recovery and efficient response.

  12. Ozone Sensing Based on Palladium Decorated Carbon Nanotubes

    Science.gov (United States)

    Colindres, Selene Capula; Aguir, Khalifa; Sodi, Felipe Cervantes; Vargas, Luis Villa; Moncayo Salazar, José A.; Febles, Vicente Garibay

    2014-01-01

    Multiwall carbon nanotubes (MWCNTs) were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd) deposited by drop coating on platinum interdigitated electrodes on a SiO2 substrate. The sensor exhibited a resistance change to ozone (O3) with a response time of 60 s at different temperatures and the capability of detecting concentrations up to 20 ppb. The sensor shows the best response when exposed to O3 at 120 °C. The device shows a very reproducible sensor performance, with high repeatability, full recovery and efficient response. PMID:24736133

  13. Palladium Decorated Graphene-Nanoribbon Network for Enhanced Gas Sensing.

    Science.gov (United States)

    Kuru, Cihan; Choi, Duyoung; Choi, Chulmin; Kim, Young Jin; Jin, Sungho

    2015-03-01

    The fabrication of large-scale graphene nanoribbon (GNR) network and its application for gas sensing are reported. A large area, nanoscale GNR network was produced by a facile approach of silver nanowires (Ag NWs) templated graphene masking and subsequent 02 plasma etching. GNR network shows significantly enhanced sensitivity to ammonia gas compared to pristine graphene layer. The gas detection sensitivity of the nanoscale GNR network is even further improved by decorating GNR network with palladium (Pd) or platinum (Pt) nanoparticles, which show a relative resistance response of 65% and 45%, respectively to 50 ppm (parts per million) of ammonia (NH3) in nitrogen (N2) at room temperature as well as good reversibility in air.

  14. Sensitization to palladium in Europe

    DEFF Research Database (Denmark)

    Muris, Joris; Goossens, An; Gonçalo, Margarida

    2015-01-01

    BACKGROUND: Recently, sodium tetrachloropalladate (Na2 PdCl4 ) was found to be a more sensitive palladium patch test allergen than palladium dichloride (PdCl2 ). OBJECTIVES: To determine the optimal test concentration of Na2 PdCl4 , to evaluate the prevalence of palladium sensitization with Na2 Pd......Cl4 and PdCl2 , and to compare the results with nickel sensitization in a European multicentre study. MATERIALS AND METHODS: In addition to the European or national baseline series including NiSO4 ·6H2 0 5% pet., consecutive patients were tested with PdCl2 and Na2 PdCl4 2%, 3% and 4% pet. in eight...... and showed suboptimal reactivity. The prevalence of palladium sensitization doubled with Na2 PdCl4 and was similar to that of nickel. Interestingly, in contrast to nickel sensitization, palladium sensitization was not related to female sex. CONCLUSIONS: Three per cent Na2 PdCl4 pet. is the most suitable...

  15. Palladium(II)-catalyzed direct alkoxylation of arenes: evidence for solvent-assisted concerted metalation deprotonation.

    Science.gov (United States)

    Anand, Megha; Sunoj, Raghavan B

    2011-09-16

    Density functional theory investigations on the mechanism of palladium acetate catalyzed direct alkoxylation of N-methoxybenzamide in methanol reveal that the key steps involve solvent-assisted N-H as well as C-H bond activations. The transition state for the critical palladium-carbon bond formation through a concerted metalation deprotonation (CMD) process leading to a palladacycle intermediate has been found to be more stable in the methanol-assisted pathway as compared to an unassisted route.

  16. 胶体钯在原子吸收光谱法测定全血中铅、镉、锰应用研究%Study on the application of colloidal palladium in the determination of lead, cadmium and manganese in blood by atomic absorption spectrometry

    Institute of Scientific and Technical Information of China (English)

    董明; 张爱华; 孙毅; 杨展鸿; 潘巧裕; 罗晓婷

    2016-01-01

    目的:研究以胶体钯作为基体改进剂在石墨炉原子吸收光谱法测定全血中铅、镉、锰的应用效果。方法用血样稀释剂将全血样品稀释10倍后,以胶体钯为基体改进剂,优化待测元素的灰化和原子化温度后,以石墨炉原子吸收光谱仪检测全血中铅、镉、锰水平,并与普通钯盐作为基体改进剂的应用效果进行比较。结果胶体钯作为基体改进剂的最佳用量为5.00μL;其可将全血中铅、镉、锰的灰化温度分别提高至900、800和1400℃,将原子化温度分别提高至1900、1800和2000℃;与普通钯盐比较,胶体钯使3种待测元素有更宽的灰化和原子化温度范围。本方法全血中铅、镉、锰分别在质量浓度0.12~100.00、0.05~4.00和0.02~10.00μg/L呈良好线性关系,相关系数均大于0.999;最低检出浓度分别为1.20、0.50和0.20μg/L(以样品稀释10倍计);平均加标回收率分别为99.2%~104.0%、102.8%~105.5%和98.3%~103.2%;批内相对标准偏差( RSD)分别为1.2%~2.6%、2.7%~5.3%和2.3%~2.8%,批间RSD分别为1.6%~3.9%、4.0%~6.1%和3.2%~4.4%。结论胶体钯用于测定全血中的铅、镉、锰,背景干扰小,有利于改善检测的精密度和灵敏度,是一种优良的基体改进剂。%Objective To study the application of colloidal palladium as a matrix modifier in the determination of lead , cadmium and manganese in whole blood by graphite furnace atomic absorption spectrometry (GFAAS).Methods The whole blood samples were diluted 10 times by blood diluents , and then the colloidal palladium was applied as a chemical modifier to improve the ashing and atomizing temperature .The levels of lead , cadmium and manganese in whole blood were determined by GFAAS .The effects of palladium chloride as a conventional matrix modifier were compared

  17. Enhancement of anodic oxidation of formic acid on palladium decorated Pt/C catalyst

    Science.gov (United States)

    Wu, Yan Ni; Liao, Shi Jun; Su, Yun Lan; Zeng, Jian Huang; Dang, Dai

    A palladium decorated Pt/C catalyst, Pt@Pd/C, is prepared by a colloidal approach with a small amount of platinum as core. It is found that the catalyst shows excellent activity towards anodic oxidation of formic acid at room temperature and its activity is 60% higher than that of Pd/C. Decoration of palladium shell on the platinum core is supported by XPS results. Due to the use of platinum as core, active components are dispersed very well and the particle sizes are smaller than those of Pd/C. The cyclic voltammetry measurement clearly shows synthetic electro-oxidation effects of formic acid on Pt@Pd/C. It is speculated that the high performance of Pt@Pd/C may result from the unique core-shell structure and synergistic effect of Pt and Pd at the interface. The preparation method for Pt@Pd/C reported in this work will provide additional options for the design of catalysts for direct formic acid fuel cell (DFAFC).

  18. Selective ligandless cloud point extraction of palladium from water and dust samples.

    Science.gov (United States)

    Mohammadi, Sayed Zia; Mohammadnezhad, Mohsen

    2015-01-01

    In this study, the phase-separation phenomenon of non-ionic surfactants was used for separation and preconcentration of Pd(II). The cloud point extraction (CPE) method is based on the formation of PdI2 which is then entrapped in the non-ionic surfactant Triton X-114. Ethanol acidified with 0.5 M HNO3 was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry. The main factors affecting CPE efficiency, such as sample solution pH, concentration of iodide ion and Triton X-114, equilibration temperature and time, were all investigated and optimized. At optimum conditions, a calibration curve was constructed for the determination of palladium according to the ligandless CPE procedure. Linearity was maintained between 1.0 to 500.0 ng/mL. The LOD based on three times the SD of the blank divided by the slope of analytical curve, (3Sb/m) was 0.3 ng/mL. Seven replicate determinations of a solution containing of 4.0 μg palladium gave a mean absorbance of 0.359 with RSD±1.85%. The high efficiency of CPE to carry out the determination of palladium in complex matrixes was demonstrated. The proposed method has been applied to the determination of trace amounts of palladium in a platinum-iridium alloy, water, and dust samples, with satisfactory results.

  19. Copper-based electrochemical sensor with palladium electrode for cathodic stripping voltammetry of manganese.

    Science.gov (United States)

    Kang, Wenjing; Pei, Xing; Bange, Adam; Haynes, Erin N; Heineman, William R; Papautsky, Ian

    2014-12-16

    In this work, we report on the development of a palladium-based, microfabricated point-of-care electrochemical sensor for the determination of manganese using square wave cathodic stripping voltammetry. Heavy metals require careful monitoring, yet current methods are too complex for a point-of-care system. Voltammetry offers an attractive approach to metal detection on the microscale, but traditional carbon, gold, or platinum electrodes are difficult or expensive to microfabricate, preventing widespread use. Our sensor uses palladium working and auxiliary electrodes and integrates them with a copper-based reference electrode for simple fabrication and compatibility with microfabrication and printed circuit board processing, while maintaining competitive performance in electrochemical detection. Copper electrodes were prepared on glass substrate using a combination of microfabrication procedures followed by electrodeposition of palladium. The disposable sensor system was formed by bonding a poly(dimethylsiloxane) (PDMS) well to the glass substrate. Cathodic stripping voltammetry of manganese using our new disposable palladium-based sensors exhibited 334 nM (18.3 ppb) limit of detection in borate buffer. The sensor was used to demonstrate manganese determination in natural water samples from a pond in Burnet Woods, located in Cincinnati, OH, and the Ohio River.

  20. Automated on-line preconcentration of palladium on different sorbents and its determination in environmental samples.

    Science.gov (United States)

    Sánchez Rojas, Fuensanta; Bosch Ojeda, Catalina; Cano Pavón, José Manuel

    2007-01-01

    The determination of noble metals in environmental samples is of increasing importance. Palladium is often employed as a catalyst in chemical industry and is also used with platinum and rhodium in motor car catalytic converters which might cause environmental pollution problems. Two different sorbents for palladium preconcentration in different samples were investigated: silica gel functionalized with 1,5-bis(di-2-pyridyl)methylene tbiocarbohydrazide (DPTH-gel) and [1,5-Bis(2-pyridyl)-3-sulphophenyI methylene thiocarbonohydrazide (PSTH) immobilised on an anion-exchange resin (Dowex lx8-200)]. The sorbents were tested in a micro-column, placed in the auto-sampler arm, at the flow rate 2.8 mL min(-1). Elution was performed with 4 M HCl and 4 M HNO3, respectively. Satisfactory results were obtained for two sorbents.

  1. Oxygen Reduction on Platinum

    DEFF Research Database (Denmark)

    Nesselberger, Markus

    This thesis investigates the electro reduction of oxygen on platinum nanoparticles, which serve as catalyst in low temperature fuel cells. Kinetic studies on model catalysts as well as commercially used systems are presented in order to investigate the particle size effect, the particle proximity...... carbon (HSAC) supported Pt nanoparticle (Pt/C) catalysts (of various size between 1 and 5 nm). The difference in SA between the individual Pt/C catalysts (1 to 5 nm) is very small and within the error of the measurements. The factor four of loss in SA when comparing platinum bulk and Pt/C can largely...

  2. Biomineralization of platinum by microorganisms

    Science.gov (United States)

    Pavlova, L. M.; Radomskaya, V. I.; Shumilova, L. P.; Ionov, A. M.; Sorokin, P.

    2017-04-01

    The mechanism of platinum biomineralization by microscopic fungi is displayed based on data of electron microscopy, infrared and X-ray photoelectronic spectroscopy. It was suggested the platinum sorption process by microscopic fungi has some stages. The initial interaction is carried out by the mechanisms of physical and chemical sorption. Hereafter the reduction process of adsorbed platinum ions up to zero state is performed, probably, for account of organic compounds, which are produced by fungi biomass as metabolism result, and the process terminates by nulvalent particles aggregating up to nanosize forms. Obtained data on the platinum biomineralization extends the concept concerning the character of forming platinum nanoparticles in carbonous paleobasin.

  3. 从复杂银阳极泥中提取金、钯工艺优化与研究%Research and Optimization on Process of Extraction Gold and Palladium from the Complex Silver Anode Slime

    Institute of Scientific and Technical Information of China (English)

    潘从明; 李明; 黄虎军; 魏建强; 李进武; 冯岩

    2014-01-01

    复杂银阳极泥回收金工艺是通过对其水溶液氯化得到分金液,使用亚钠进行还原得到合格金粉,由于外购原料增多,经水溶液氯化得到的分金液含有铂钯,分金液亚钠还原效率仅能控制在65%左右,需二次亚钠还原回收金。然而,得到的二次金粉中钯含量超标,返工易富集循环,不利于钯回收。本研究改进了复杂银阳极泥氯化分金液在进行亚钠一次还原后提取金、钯的工艺,具体工艺流程:首先,通过小型试验对还原后液开展DBC萃金并提纯金工艺,萃余液在进行传统的提取钯工艺的基础上,采用水合肼还原二氯二氨络亚钯得到钯黑。之后,进行工业扩大试验,确定最佳工艺技术条件。整个工艺过程中,金和钯的直收率分别为99.52%和94.53%,技术指标良好。%Extraction gold from the complex silver anode slime is that points of gold liquid can be obtained by chloridizing the aqueous solution of the silver anode slime,and then qualified gold powders are obtained after reducing sodium nitrite.Because of the more outsourcing raw material,obtained the points of gold liquid contain platinum as well as palladium,the efficiency of sodium nitrite reduction of the liquid can only be controlled around 65%,thus sodium nitrite reduction for the second time is required.However,the content of palladium in the gold powders exceed standard,and the reword can lead to enrichment of circulation,which will go against the recycle of palladium.Extraction gold and palladium from the complex silver anode slime after sodium nitrite reduction for the first time.Firstly,on the basis of traditional technology of extraction in raffinate and small text on DBC extraction of gold,and we apply palladium black hydrazine hydrate to reduce two chlorine two ammino and palladium so as to get palladium black.And then Industry expanding test is carried out in order to identify the best condition during

  4. Platinum single crystal electrodes for the electrocatalysis of methane oxidation

    Directory of Open Access Journals (Sweden)

    Mayara Munaretto

    2011-03-01

    Full Text Available The main objective of this paper is to characterize the voltammetric profiles of platinum single crystals of low Miller indexes Pt(100 and Pt(110 and study their catalytic activities on the oxidation of methane. In this way, it was developed a metallic surface modified by presence of other metal oxide, which presents catalytic activity for this reaction. It is well known that the electrooxidation of methane (CH4 leads mainly to the formation of CO2 and H2O, however, the oxidation can also lead to the formation of CO, a reaction intermediate that has strong interaction with metal surfaces, such as platinum. This molecule tends to accumulate on the platinum surface and to passive it, due to the self-poisoning, decreasing its catalytic activity. Therefore, the main aim of this work was the development of a platinum electrode modified by deposition of titanium oxide, which presented electrocatalytic properties for the oxidation of methane.

  5. Recovery of Elemental Palladium by Shewanella putrefaciens

    Science.gov (United States)

    Akasaka, S.; Xia, X.; Sawada, K.; Enokida, Y.; Yamamoto, I.; Ohnuki, T.

    2006-12-01

    Microbial reduction of metals plays an important role in environmental behavior and provides a technique for the recovery of metals from industrial wastewater. Recently, demand for platinum group metals (PGMs) increases by their catalytic properties. The extreme rarity of PGMs have led to a growing interest in their recovery. Palladium, one of PGMs, has different oxidation states of Pd(II) and Pd(0). The oxidized form of Pd(II) is soluble, while the reduced form of Pd(0) is insoluble. In this study, microbial reduction of palladium by Fe(III)- reducing bacterium, Shewanella putrefaceins was conducted. This bacterium is known to be capable of reducing metals, such as Mn(IV), U(VI), or Tc(VII) with organic C or H2 as an electron donor. In order to investigate the potential of S. putrefaciens to reduce Pd(II) in solution, resting cells or heat-killed cells were suspended under anaerobic conditions with lactate or H2 as an electron donor. The cells of S. putrefaciens (NBRC3908) were grown in aerobic medium, harvested by centrifugation, and then washed with 25 mmol/dm3 HEPES and 100 mmol/dm3 NaCl (HEPES-NaCl) solution (pH 7.0). The heat-killed cells were autoclaved for 20 min at 121 degrees C. The cell suspension (21.5 mg in dry weight) was resuspended in the HEPES-NaCl solution which contained 1.0 mmol/dm3 Na2PdCl4 (Wako Pure chemical Industries, Ltd). The suspensions were bubbled with N2 for 15 min before 10 mmol/dm3 lactate or 4.8 v/v% H2 was added. The suspensions were then incubated at 30 degrees C. Redox potential (Eh) and pH of the solutions were measured in an inert glove box with Ar gas. Concentration of Pd(II) was measured by Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). Deposited Pd and cells were analyzed by X-ray powder diffraction (XRD) and Scanning Electron Microscope (SEM) with Energy-Dispersive Spectroscopy (EDS). Approximately 86% of Pd(II) of the initial concentration was removed from solution by the resting cells within 24 h when

  6. Bio-inspired routes for synthesizing efficient nanoscale platinum electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jennifer N. [Univ. of California, San Diego, CA (United States); Wang, Joseph [Univ. of California, San Diego, CA (United States)

    2014-08-31

    The overall objective of the proposed research is to use fundamental advances in bionanotechnology to design powerful platinum nanocrystal electrocatalysts for fuel cell applications. The new economically-viable, environmentally-friendly, bottom-up biochemical synthetic strategy will produce platinum nanocrystals with tailored size, shape and crystal orientation, hence leading to a maximum electrochemical reactivity. There are five specific aims to the proposed bio-inspired strategy for synthesizing efficient electrocatalytic platinum nanocrystals: (1) isolate peptides that both selectively bind particular crystal faces of platinum and promote the nucleation and growth of particular nanocrystal morphologies, (2) pattern nanoscale 2-dimensional arrays of platinum nucleating peptides from DNA scaffolds, (3) investigate the combined use of substrate patterned peptides and soluble peptides on nanocrystal morphology and growth (4) synthesize platinum crystals on planar and large-area carbon electrode supports, and (5) perform detailed characterization of the electrocatalytic behavior as a function of catalyst size, shape and morphology. Project Description and Impact: This bio-inspired collaborative research effort will address key challenges in designing powerful electrocatalysts for fuel cell applications by employing nucleic acid scaffolds in combination with peptides to perform specific, environmentally-friendly, simultaneous bottom-up biochemical synthesis and patterned assembly of highly uniform and efficient platinum nanocrystal catalysts. Bulk synthesis of nanoparticles usually produces a range of sizes, accessible catalytic sites, crystal morphologies, and orientations, all of which lead to inconsistent catalytic activities. In contrast, biological systems routinely demonstrate exquisite control over inorganic syntheses at neutral pH and ambient temperature and pressures. Because the orientation and arrangement of the templating biomolecules can be precisely

  7. Gravimetric determination and radiochemical separation of palladium(II) with ethyl-. cap alpha. -isonitrosoacetoacetate

    Energy Technology Data Exchange (ETDEWEB)

    Manwati, S.J.; Sawant, A.D. (Institute of Science, Bombay (India). Inorganic and Nuclear Chemistry Lab.)

    1984-10-01

    The use of ethyl-..cap alpha..-isonitrosoacetoacetate for the determination of palladium is reported. Pd can be estimated quantitatively from 0.5M to 2M HCl solution. Accurate results are obtained in 1M solution with an accuracy better than 1%. Decontamination values against platinum and other metals usually associated with Pd are greater than 10/sup 5/. The time required for gravimetric determination is about an hour, for radiochemical separation about 25 min and the recovery is better than 90%.

  8. Palladium-Catalysed Coupling Reactions

    NARCIS (Netherlands)

    de Vries, Johannes G.; Beller, M; Blaser, HU

    2012-01-01

    Palladium-catalysed coupling reactions have gained importance as a tool for the production of pharmaceutical intermediates and to a lesser extent also for the production of agrochemicals, flavours and fragrances, and monomers for polymers. In this review only these cases are discussed where it seems

  9. E platinum, a newly synthesized platinum compound, induces apoptosis through ROS-triggered ER stress in gastric carcinoma cells.

    Science.gov (United States)

    Wang, Xiaoping; Guo, Qinglong; Tao, Lei; Zhao, Li; Chen, Yan; An, Teng; Chen, Zhen; Fu, Rong

    2017-01-01

    Gastric cancer (GC) is still one of the leading causes of death in cancer-related diseases. In this study, we aimed to investigate the antitumor effect of E Platinum, a newly platinum-based chemotherapeutic agent bearing the basic structure of Oxaliplatin, in a variety of gastric carcinoma cells and the underlying mechanisms. We demonstrated that E Platinum significantly induced apoptosis in gastric cancer cells via mitochondrial apoptotic pathway as a result of increased reactive oxygen species (ROS). We also found that E Platinum enhanced Ca(2+) flux out from the endoplasmic reticulum by increasing the protein expression of IP3R type 1 (IP3R1) and decreasing the expression of ERp44. Dysfunction of Ca(2+) homeostasis in endoplasmic reticulum (ER) leads to accumulation of unfolded proteins and ER stress. Mechanically, E Platinum increased ER stress associated protein expression such as GRP78, p-PERK, p-eIF2α, ATF4, and CHOP. However, knocking down CHOP reversed E Platinum-induced apoptosis by blocking mitochondrial apoptotic pathway. Furthermore, 10 mg/kg of E Platinum significantly suppressed BGC-823 tumor growth in vivo without toxicity, which correlated with induction of apoptosis and expression of ER stress related proteins in tumor tissues. Taken together, E Platinum inhibited tumor growth and induced apoptosis by ROS-mediated ER stress activation both in vitro and in vivo. Our study indicated that E Platinum may be a potential and effective treatment for gastric cancer in clinical. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Palladium interaction with silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, M., E-mail: Marialuisa.Gentile@manchester.ac.uk [Centre for Nuclear Energy Technology (C-NET), School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M13 9PL (United Kingdom); Xiao, P. [Materials Science Centre, School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom); Abram, T. [Centre for Nuclear Energy Technology (C-NET), School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2015-07-15

    In this work the palladium interaction with silicon carbide is investigated by means of complementary analytical techniques such as thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Thermoscans were carried out on pellets of palladium, α-SiC and β-SiC high purity powders in the temperature range comprised between 293 K and 1773 K, in order to study the effect of temperature on the palladium-silicon carbide reaction. Thermoscans of α-SiC pellets containing 5 at.%Pd show that during differential calorimetry scans three exothermic peaks occurred at 773 K, 1144 K and 1615 K, while thermoscans of β-SiC pellets containing 3 at.%Pd and 5 at.%Pd do not show peaks. For the pellet α-SiC–5 at.%Pd XRD spectra reveal that the first peak is associated with the formation of Pd{sub 3}Si and SiO{sub 2} phases, while the second peak and the third peak are correlated with the formation of Pd{sub 2}Si phase and the active oxidation of silicon carbide respectively. Thermogravimetry scans show weight gain and weight loss peaks due to the SiO{sub 2} phase formation and the active oxidation. Additionally XPS fittings reveal the development of SiC{sub x}O{sub y} phase during the first exothermic peak up to the temperature of 873 K. The experimental data reveals that alpha silicon carbide is attacked by palladium at lower temperatures than beta silicon carbide and the reaction mechanism between silicon carbide and palladium is strongly affected by silicon carbide oxidation.

  11. Palladium interaction with silicon carbide

    Science.gov (United States)

    Gentile, M.; Xiao, P.; Abram, T.

    2015-07-01

    In this work the palladium interaction with silicon carbide is investigated by means of complementary analytical techniques such as thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Thermoscans were carried out on pellets of palladium, α-SiC and β-SiC high purity powders in the temperature range comprised between 293 K and 1773 K, in order to study the effect of temperature on the palladium-silicon carbide reaction. Thermoscans of α-SiC pellets containing 5 at.%Pd show that during differential calorimetry scans three exothermic peaks occurred at 773 K, 1144 K and 1615 K, while thermoscans of β-SiC pellets containing 3 at.%Pd and 5 at.%Pd do not show peaks. For the pellet α-SiC-5 at.%Pd XRD spectra reveal that the first peak is associated with the formation of Pd3Si and SiO2 phases, while the second peak and the third peak are correlated with the formation of Pd2Si phase and the active oxidation of silicon carbide respectively. Thermogravimetry scans show weight gain and weight loss peaks due to the SiO2 phase formation and the active oxidation. Additionally XPS fittings reveal the development of SiCxOy phase during the first exothermic peak up to the temperature of 873 K. The experimental data reveals that alpha silicon carbide is attacked by palladium at lower temperatures than beta silicon carbide and the reaction mechanism between silicon carbide and palladium is strongly affected by silicon carbide oxidation.

  12. Synthesis and characterization of nanostructured palladium-based alloy electrocatalysts

    Science.gov (United States)

    Sarkar, Arindam

    Low temperature fuel cells like proton exchange membrane fuel cells (PEMFC) are expected to play a crucial role in the future hydrogen economy, especially for transportation applications. These electrochemical devices offer significantly higher efficiency compared to conventional heat engines. However, use of exotic and expensive platinum as the electrocatalyst poses serious problems for commercial viability. In this regard, there is an urgent need to develop low-platinum or non-platinum electrocatalysts with electrocatalytic activity for the oxygen reduction reaction (ORR) superior or comparable to that of platinum. This dissertation first investigates non-platinum, palladium-based alloy electrocatalysts for ORR. Particularly, Pd-M (M = Mo and W) alloys are synthesized by a novel thermal decomposition of organo-metallic precursors. The carbon-supported Pd-M (M = Mo, W) electrocatalyts are then heat treated up to 900°C in H2 atmosphere and investigated for their phase behavior. Cyclic voltammetry (CV) and rotating disk electrode (RDE) measurements reveal that the alloying of Pd with Mo or W significantly enhances the catalytic activity for ORR as well as the stability (durability) of the electrocatalysts. Additionally, both the alloy systems exhibit high tolerance to methanol, which is particularly advantageous for direct methanol fuel cells (DMFC). The dissertation then focuses on one-pot synthesis of carbon-supported multi-metallic Pt-Pd-Co nanoalloys by a rapid microwave-assisted solvothermal (MW-ST) method. The multi-metallic alloy compositions synthesized by the MW-ST method show much higher catalytic activity for ORR compared to their counterparts synthesized by the conventional borohydride reduction method. Additionally, a series of Pt encapsulated Pd-Co nanoparticle electrocatalysts are synthesized by the MW-ST method and characterized to understand their phase behavior, surface composition, and electrocatalytic activity for ORR. Finally, the dissertation

  13. Cisplatin and platinum drugs at the molecular level. (Review).

    Science.gov (United States)

    Boulikas, Teni; Vougiouka, Maria

    2003-01-01

    Over twenty years of intensive work toward improvement of cisplatin, and with hundreds of platinum drugs tested, has resulted in the introduction of the widely used carboplatin and of oxaliplatin used only for a very narrow spectrum of cancers. A number of interesting platinum compounds including the orally administered platinum drug JM216, nedaplatin, the sterically hindered platinum(II) complex ZD0473, the trinuclear platinum complex BBR3464, and the liposomal forms Lipoplatin and SPI-77 are under clinical evaluation. This review summarizes the molecular mechanisms of platinum compounds for DNA damage, DNA repair and induction of apoptosis via activation or modulation of signaling pathways and explores the basis of platinum resistance. Cisplatin, carboplatin, oxaliplatin and most other platinum compounds induce damage to tumors via induction of apoptosis; this is mediated by activation of signal transduction leading to the death receptor mechanisms as well as mitochondrial pathways. Apoptosis is responsible for the characteristic nephrotoxicity, ototoxicity and most other toxicities of the drugs. The major limitation in the clinical applications of cisplatin has been the development of cisplatin resistance by tumors. Mechanisms explaining cisplatin resistance include the reduction in cisplatin accumulation inside cancer cells because of barriers across the cell membrane, the faster repair of cisplatin adducts, the modulation of apoptotic pathways in various cells, the upregulation in transcription factors, the loss of p53 and other protein functions and a higher concentration of glutathione and metallothioneins in some type of tumors. A number of experimental strategies to overcome cisplatin resistance are at the preclinical or clinical level such as introduction of the bax gene, inhibition of the JNK pathway, introduction of a functional p53 gene, treatment of tumors with aldose reductase inhibitors and others. Particularly important are combinations of platinum

  14. Platinum Acetylide Two-Photon Chromophores (Preprint)

    Science.gov (United States)

    2007-04-01

    the higher energy range that lead to its photodegradation . Secondly, because there is a quadratic dependence of two-photon absorption (2PA) on the...to either an electron donating amino- fluorenyl or electron withdrawing benzothiazolyl-fluorene that are themselves known as two-photon absorbing dyes ...groups in place of phenyl groups have shown a doubling of the intrinsic cr2value at 740 nm.40,41In this paper we describe novel platinum dyes that

  15. Leaching platinum-group metals in a sulfuric acid/chloride solution

    Science.gov (United States)

    Mahmoud, M. H. H.

    2003-04-01

    A leaching process was established based on the ability of platinum-group metals to form stable chloro-complexes in acidic chloride solutions. Industrial catalyst losses were examined for the recovery of platinum, palladium, and rhodium by leaching with a mixture of sulfuric acid and sodium chloride to avoid using aqua regia or autoclave conditions. Extraction of platinum and rhodium in 60% H2SO4 at 135°C steadily increased with increasing NaCl concentrations reaching 95% and 85%, respectively, at 0.1 M NaCl after two hours. By comparison, palladium was dissolved more quickly but also reached 85% under the same conditions. Extraction of each metal increased with temperatures up to 125°C but plateaued at higher temperatures. Similar behavior was observed with increasing H2SO4 concentrations up to 60%. More than 99% extraction of each metal was obtained after ten hours using 0.1 M NaCl and 60% H2SO4 at 125°C.

  16. Spontaneous incorporation of gold in palladium-based ternary nanoparticles makes durable electrocatalysts for oxygen reduction reaction

    Science.gov (United States)

    Wang, Deli; Liu, Sufen; Wang, Jie; Lin, Ruoqian; Kawasaki, Masahiro; Rus, Eric; Silberstein, Katharine E.; Lowe, Michael A.; Lin, Feng; Nordlund, Dennis; Liu, Hongfang; Muller, David A.; Xin, Huolin L.; Abruña, Héctor D.

    2016-01-01

    Replacing platinum by a less precious metal such as palladium, is highly desirable for lowering the cost of fuel-cell electrocatalysts. However, the instability of palladium in the harsh environment of fuel-cell cathodes renders its commercial future bleak. Here we show that by incorporating trace amounts of gold in palladium-based ternary (Pd6CoCu) nanocatalysts, the durability of the catalysts improves markedly. Using aberration-corrected analytical transmission electron microscopy in conjunction with synchrotron X-ray absorption spectroscopy, we show that gold not only galvanically replaces cobalt and copper on the surface, but also penetrates through the Pd–Co–Cu lattice and distributes uniformly within the particles. The uniform incorporation of Au provides a stability boost to the entire host particle, from the surface to the interior. The spontaneous replacement method we have developed is scalable and commercially viable. This work may provide new insight for the large-scale production of non-platinum electrocatalysts for fuel-cell applications. PMID:27336795

  17. Spontaneous incorporation of gold in palladium-based ternary nanoparticles makes durable electrocatalysts for oxygen reduction reaction

    Science.gov (United States)

    Wang, Deli; Liu, Sufen; Wang, Jie; Lin, Ruoqian; Kawasaki, Masahiro; Rus, Eric; Silberstein, Katharine E.; Lowe, Michael A.; Lin, Feng; Nordlund, Dennis; Liu, Hongfang; Muller, David A.; Xin, Huolin L.; Abruña, Héctor D.

    2016-06-01

    Replacing platinum by a less precious metal such as palladium, is highly desirable for lowering the cost of fuel-cell electrocatalysts. However, the instability of palladium in the harsh environment of fuel-cell cathodes renders its commercial future bleak. Here we show that by incorporating trace amounts of gold in palladium-based ternary (Pd6CoCu) nanocatalysts, the durability of the catalysts improves markedly. Using aberration-corrected analytical transmission electron microscopy in conjunction with synchrotron X-ray absorption spectroscopy, we show that gold not only galvanically replaces cobalt and copper on the surface, but also penetrates through the Pd-Co-Cu lattice and distributes uniformly within the particles. The uniform incorporation of Au provides a stability boost to the entire host particle, from the surface to the interior. The spontaneous replacement method we have developed is scalable and commercially viable. This work may provide new insight for the large-scale production of non-platinum electrocatalysts for fuel-cell applications.

  18. Optimizing treatment of the partially platinum-sensitive ovarian cancer patient.

    Science.gov (United States)

    Colombo, Nicoletta

    2013-12-01

    Ovarian cancer is the leading cause of gynecological cancer deaths worldwide. Despite primary treatment with platinum-containing regimens, the majority of women will experience recurrent disease and subsequent death. Recurrent ovarian cancer remains a challenge for successful management, and the choice of second-line chemotherapy is complex due to the range of different factors that need to be considered. One of the main considerations is the platinum-free interval and, specifically, the optimal treatment for patients who are partially platinum-sensitive (platinum-free interval: 6-12 months). Data from the large, multicenter, randomized OVA-301 study have shown that combined trabectedin-pegylated liposomal doxorubicin (PLD) significantly prolonged median overall survival compared with PLD alone (p = 0.0027) in 214 patients with partially platinum-sensitive advanced relapsed ovarian cancer. Furthermore, in OVA-301 patients with partially platinum-sensitive disease who received platinum therapy immediately after disease progression (n = 94), final median overall survival was improved by 9 months (p = 0.0153) in trabectedin-PLD patients compared with PLD alone. In addition to demonstrating a survival advantage, trabectedin-PLD may also allow the treatment of patients having not yet recovered from previous platinum toxicity. In summary, the data suggest the use of combined trabectedin-PLD as a second-line treatment option in patients with partially platinum-sensitive recurrent ovarian cancer, followed by a third-line platinum-containing regimen.

  19. Palladium in cubic silicon carbide: Stability and kinetics

    Science.gov (United States)

    Roma, Guido

    2009-12-01

    Several technological applications of silicon carbide are concerned with the introduction of palladium impurities. Be it intentional or not, this may lead to the formation of silicides. Not only this process is not well understood, but the basic properties of palladium impurities in silicon carbide, such as solubility or diffusion mechanisms, are far from being known. Here the stability and kinetics of isolated Pd impurities in cubic silicon carbide are studied by first principles calculations in the framework of density functional theory. The preferential insertion sites, as well as the main migration mechanisms, are analyzed and presented here, together with the results for solution and migration energies. The early stages of nucleation are discussed based on the properties of isolated impurities and the smallest clusters.

  20. Platinum nitride with fluorite structure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Rong; Zhang, Xiao-Feng

    2005-01-31

    The mechanical stability of platinum nitride has been studied using first-principles calculations. By calculating the single-crystal elastic constants, we show that platinum nitride can be stabilized in the fluorite structure, in which the nitrogen atoms occupy all the tetrahedral interstitial sites of the metal lattice. The stability is attributed to the pseudogap effect from analysis of the electronic structure.

  1. 银电解过程中钯的回收%Recovery of Palladium from Silver Electrolysis Process

    Institute of Scientific and Technical Information of China (English)

    李栋

    2012-01-01

    According to the distribution characteristics of platinum and palladium in gold and silver metallurgical process, an new technology for recovering palladium from silver electrolytic anode mud by selective enrichment and separation with C4H9OCSSNa, (NH4)2PdCl6-Pd(NH4)2Cl2 joint precipitation, and hy-drazine hydrate reduction was presented. The results show that the purity of product sponge palladium is more than 99. 95%; the direct recovery rate is over 97%. This process has the advantages of good selective separation of palladium, no removing nitrate in the process and stable quality of product.%针对金银冶金过程中铂钯的分布特点,提出了采用黄药富集分离、氯钯酸铵-二氯二氨络亚钯联合沉淀、水合肼还原的方法从银电解阳极泥中回收钯的新工艺.结果 表明,所得海绵钯纯度大于99.95%,直收率大于97%.该工艺具有选择性分离钯效果好、过程无需赶硝、产品质量稳定等优点.

  2. Thermodynamics of the hybrid interaction of hydrogen with palladium nanoparticles

    Science.gov (United States)

    Griessen, Ronald; Strohfeldt, Nikolai; Giessen, Harald

    2016-03-01

    Palladium-hydrogen is a prototypical metal-hydrogen system. It is therefore not at all surprising that a lot of attention has been devoted to the absorption and desorption of hydrogen in nanosized palladium particles. Several seminal articles on the interaction of H with Pd nanocubes and nanoparticles have recently been published. Although each article provides for the first time detailed data on specific aspects of hydrogen in nanoparticles, they individually do not contain enough information to draw firm conclusions about the involved mechanisms. Here, we show that the large body of data available so far in literature exhibits general patterns that lead to unambiguous conclusions about the processes involved in H absorption and desorption in Pd nanoparticles. On the basis of a remarkably robust scaling law for the hysteresis in absorption-desorption isotherms, we show that hydrogen absorption in palladium nanoparticles is consistent with a coherent interface model and is thus clearly different from bulk Pd behaviour. However, H desorption occurs fully coherently only for small nanoparticles (typically smaller than 50 nm) at temperatures sufficiently close to the critical temperature. For larger particles it is partially incoherent, as in bulk, where dilute α-PdHx and high concentration β-PdHx phases coexist.

  3. Thermodynamics of the hybrid interaction of hydrogen with palladium nanoparticles.

    Science.gov (United States)

    Griessen, Ronald; Strohfeldt, Nikolai; Giessen, Harald

    2016-03-01

    Palladium-hydrogen is a prototypical metal-hydrogen system. It is therefore not at all surprising that a lot of attention has been devoted to the absorption and desorption of hydrogen in nanosized palladium particles. Several seminal articles on the interaction of H with Pd nanocubes and nanoparticles have recently been published. Although each article provides for the first time detailed data on specific aspects of hydrogen in nanoparticles, they individually do not contain enough information to draw firm conclusions about the involved mechanisms. Here, we show that the large body of data available so far in literature exhibits general patterns that lead to unambiguous conclusions about the processes involved in H absorption and desorption in Pd nanoparticles. On the basis of a remarkably robust scaling law for the hysteresis in absorption-desorption isotherms, we show that hydrogen absorption in palladium nanoparticles is consistent with a coherent interface model and is thus clearly different from bulk Pd behaviour. However, H desorption occurs fully coherently only for small nanoparticles (typically smaller than 50 nm) at temperatures sufficiently close to the critical temperature. For larger particles it is partially incoherent, as in bulk, where dilute α-PdHx and high concentration β-PdHx phases coexist.

  4. Characterization of the Sukinda and Nausahi ultramafic complexes, Orissa, India by platinum-group element geochemistry

    Science.gov (United States)

    Page, N.J.; Banerji, P.K.; Haffty, J.

    1985-01-01

    Samples of 20 chromitite, 14 ultramafic and mafic rock, and 9 laterite and soil samples from the Precambrian Sukinda and Nausahi ultramafic complexes, Orissa, India were analyzed for platinum-group elements (PGE). The maximum concentrations are: palladium, 13 parts per billion (ppb); platinum, 120 ppb; rhodium, 21 ppb; iridium, 210 ppb; and ruthenium, 630 ppb. Comparison of chondrite-normalized ratios of PGE for the chromitite samples of lower Proterozoic to Archean age with similar data from Paleozoic and Mesozoic ophiolite complexes strongly implies that these complexes represent Precambrian analogs of ophiolite complexes. This finding is consistent with the geology and petrology of the Indian complexes and suggests that plate-tectonic and ocean basin developement models probably apply to some parts of Precambrian shield areas. ?? 1985.

  5. Platinum-group elements: so many excellent properties

    Science.gov (United States)

    Zientek, Michael L.; Loferski, Patricia J.

    2014-01-01

    The platinum-group elements (PGE) include platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals have similar physical and chemical properties and occur together in nature. The properties of PGE, such as high melting points, corrosion resistance, and catalytic qualities, make them indispensable to many industrial applications. PGE are strategic and critical materials for many nations because they are essential for important industrial applications but are mined in a limited number of places and have no adequate substitutes. Exploration and mining companies have found approximately 104,000 metric tons of PGE (with minor gold) in mineral deposits around the world that could be developed. For PGE, almost all known production and resources are associated with three geologic features: the Bushveld Complex, a layered mafic-to-ultramafic intrusion in South Africa; the Great Dyke, a layered mafic-to-ultramafic intrusion in Zimbabwe; and sill-like intrusions associated with flood basalts in the Noril’sk-Talnakh area, Russia. To help predict where PGE supplies might be located, USGS scientists study how and where PGE resources are concentrated in the Earth's crust and use that knowledge to assess the likelihood that undiscovered PGE deposits may exist. Techniques used for assessing mineral resources were developed by the USGS to support the stewardship of Federal lands and evaluate mineral resource availability in a global context. The USGS also compiles statistics and information on the worldwide supply, demand, and flow of PGE. These data are all used to inform U.S. national policymakers.

  6. Platinum in Earth surface environments

    Science.gov (United States)

    Reith, F.; Campbell, S. G.; Ball, A. S.; Pring, A.; Southam, G.

    2014-04-01

    Platinum (Pt) is a rare precious metal that is a strategic commodity for industries in many countries. The demand for Pt has more than doubled in the last 30 years due to its role in the catalytic conversion of CO, hydrocarbons and NOx in modern automobiles. To explore for new Pt deposits, process ores and deal with ecotoxicological effects of Pt mining and usage, the fundamental processes and pathways of Pt dispersion and re-concentration in surface environments need to be understood. Hence, the aim of this review is to develop a synergistic model for the cycling of Pt in Earth surface environments. This is achieved by integrating the geological/(biogeo)chemical literature, which focuses on naturally occurring Pt mobility around ore deposits, with the environmental/ecotoxicological literature dealing with anthropogenic Pt dispersion. In Pt deposits, Pt occurs as sulfide-, telluride- and arsenide, native metal and alloyed to other PGEs and iron (Fe). Increased mining and utilization of Pt combined with the burning of fossil fuels have led to the dispersion of Pt-containing nano- and micro-particles. Hence, soils and sediments in industrialized areas, urban environments and along major roads are now commonly Pt enriched. Platinum minerals, nuggets and anthropogenic particles are transformed by physical and (bio)geochemical processes. Complexation of Pt ions with chloride, thiosulfate, ammonium, cyanide, low- and high molecular weight organic acids (LMWOAs and HMWOAs) and siderophores can facilitate Pt mobilization. Iron-oxides, clays, organic matter and (micro)biota are known to sequester Pt-complexes and -particles. Microbes and plants are capable of bioaccumulating and reductively precipitating mobile Pt complexes. Bioaccumulation can lead to toxic effects on plants and animals, including humans. (Bio)mineralization in organic matter-rich sediments can lead to the formation of secondary Pt particles and -grains. Ultimately, Pt is enriched in oceanic sediments

  7. Palladium-Catalyzed Cross-Coupling Reactions of Perfluoro Organic Compounds

    Directory of Open Access Journals (Sweden)

    Masato Ohashi

    2014-09-01

    Full Text Available In this review, we summarize our recent development of palladium(0-catalyzed cross-coupling reactions of perfluoro organic compounds with organometallic reagents. The oxidative addition of a C–F bond of tetrafluoroethylene (TFE to palladium(0 was promoted by the addition of lithium iodide, affording a trifluorovinyl palladium(II iodide. Based on this finding, the first palladium-catalyzed cross-coupling reaction of TFE with diarylzinc was developed in the presence of lithium iodide, affording α,β,β-trifluorostyrene derivatives in excellent yield. This coupling reaction was expanded to the novel Pd(0/PR3-catalyzed cross-coupling reaction of TFE with arylboronates. In this reaction, the trifluorovinyl palladium(II fluoride was a key reaction intermediate that required neither an extraneous base to enhance the reactivity of organoboronates nor a Lewis acid additive to promote the oxidative addition of a C–F bond. In addition, our strategy utilizing the synergetic effect of Pd(0 and lithium iodide could be applied to the C–F bond cleavage of unreactive hexafluorobenzene (C6F6, leading to the first Pd(0-catalyzed cross-coupling reaction of C6F6 with diarylzinc compounds.

  8. Highly trifluoromethylated platinum compounds.

    Science.gov (United States)

    Martínez-Salvador, Sonia; Forniés, Juan; Martín, Antonio; Menjón, Babil

    2011-07-11

    The homoleptic, square-planar organoplatinum(II) compound [NBu(4)](2) [Pt(CF(3))(4)] (1) undergoes oxidative addition of CF(3) I under mild conditions to give rise to the octahedral organoplatinum(IV) complex [NBu(4)](2) [Pt(CF(3))(5)I] (2). This highly trifluoromethylated species reacts with Ag(+) salts of weakly coordinating anions in Me(2)CO under a wet-air stream to afford the aquo derivative [NBu(4)][Pt(CF(3))(5) (OH(2))] (4) in around 75% yield. When the reaction of 2 with the same Ag(+) salts is carried out in MeCN, the solvento compound [NBu(4) ][Pt(CF(3))(5)(NCMe)] (5) is obtained in around 80% yield. The aquo ligand in 4 as well as the MeCN ligand in 5 are labile and can be cleanly replaced by neutral and anionic ligands to furnish a series of pentakis(trifluoromethyl)platinate(IV) compounds with formulae [NBu(4)][Pt(CF(3))(5) (L)] (L=CO (6), pyridine (py; 7), tetrahydrothiophene (tht; 8)) and [NBu(4)](2) [Pt(CF(3))(5)X] (X=Cl (9), Br (10)). The unusual carbonyl-platinum(IV) derivative [NBu(4)][Pt(CF(3))(5) (CO)] (6) is thermally stable and has a ν(CO) of 2194 cm(-1). The crystal structures of 2⋅CH(2)Cl(2), 5, [PPh(4) ][Pt(CF(3))(5)(CO)] (6'), and 7 have been established by X-ray diffraction methods. Compound 2 has shown itself to be a convenient entry to the chemistry of highly trifluoromethylated platinum compounds. To the best of our knowledge, compounds 2 and 4-10 are the organoelement compounds with the highest CF(3) content to have been isolated and adequately characterized to date.

  9. Understanding platinum-induced ototoxicity.

    Science.gov (United States)

    Langer, Thorsten; am Zehnhoff-Dinnesen, Antoinette; Radtke, Susanne; Meitert, Johannes; Zolk, Oliver

    2013-08-01

    Childhood cancer survival rates are now nearly 80% in more developed European countries because of improved therapies and better supportive care. Platinum chemotherapy drugs, such as cisplatin and carboplatin, are the cornerstone of many effective therapeutic protocols for childhood cancer. However, the antitumor efficacy of cisplatin and carboplatin comes at the cost of ototoxicity, which affects at least 60% of pediatric patients. Although ototoxicity is not life threatening, it can have debilitating effects on patients' quality of life. Recently, many initiatives have been launched with the ultimate goal of reducing cisplatin and high-dose carboplatin ototoxicity without compromising antitumor efficacy. This review addresses the incidence of platinum ototoxicity and its clinical presentation, time course, and early diagnostic evaluation. Genetic and non-genetic risk factors for platinum-associated ototoxicity, and their predictive value, are discussed. Recent developments in the prevention of platinum ototoxicity are also summarized. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Inorganic nanocarriers for platinum drug delivery

    Directory of Open Access Journals (Sweden)

    Ping’an Ma

    2015-12-01

    Full Text Available Nowadays platinum drugs take up almost 50% of all the clinically used anticancer drugs. Besides cisplatin, novel platinum agents including sterically hindered platinum (II drugs, chemically reductive platinum (IV drugs, photosensitive platinum (IV drugs, and multinuclear platinum drugs have been developed recently, with a few entering clinic trials. Rapid development of nanobiotechnology makes targeted delivery of anticancer platinum agents to the tumor site possible, while simultaneously minimizing toxicity and maximizing the drug efficacy. Being versatile drug carriers to deliver platinum drugs, inorganic nanovehicles such as gold nanoparticles, iron oxide nanomaterials, carbon nanotubes, mesoporous nanosilica, metal-organic frameworks (MOFs, have been extensively studied over the past decades. In contrast to conventional polymeric and lipid nanoparticles, inorganic nanoparticles based drug carriers are peculiar as they have shown excellent theranostic effects, revealing themselves an indispensable part of future nanomedicine. Here, we will elaborate recent research advances on fabrication of inorganic nanoparticles for platinum drug delivery.

  11. Platinum availability for future automotive technologies.

    Science.gov (United States)

    Alonso, Elisa; Field, Frank R; Kirchain, Randolph E

    2012-12-04

    Platinum is an excellent catalyst, can be used at high temperatures, and is stable in many aggressive chemical environments. Consequently, platinum is used in many current industrial applications, notably automotive catalytic converters, and prospective vehicle fuel cells are expected to rely upon it. Between 2005 and 2010, the automotive industry used approximately 40% of mined platinum. Future automotive industry growth and automotive sales shifts toward new technologies could significantly alter platinum demand. The potential risks for decreased platinum availability are evaluated, using an analysis of platinum market characteristics that describes platinum's geophysical constraints, institutional efficiency, and dynamic responsiveness. Results show that platinum demand for an automotive fleet that meets 450 ppm greenhouse gas stabilization goals would require within 10% of historical growth rates of platinum supply before 2025. However, such a fleet, due largely to sales growth in fuel cell vehicles, will more strongly constrain platinum supply in the 2050 time period. While current platinum reserves are sufficient to satisfy this increased demand, decreasing platinum ore grade and continued concentration of platinum supply in a single geographic area are availability risk factors to platinum end-users.

  12. Geochemistry of Platinum Group and Rare Earth Elements of the Polymetallic Layer in the Lower Cambrian,Weng'an,Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    FU Yong; WU Chaodong; GUAN Ping; QU Wenjun; CHEN Jiafu

    2009-01-01

    The black shales of the Lower Cambrian Niutitang Formation in Weng'an.on the Yangtze platform of south China,contain voluminous polymetallic sulfide deposits.A comprehensive geochemical investigation of trace,rare earth,and platinum group elements(PGE)has been undertaken in order to discuss its ore genesis and correlation with the tectono.depositional setting.The ore-bearing layers enrich molybdenum(Mo),nickeI(Ni),vanadium(V),lead(Pb),strontium(Sr), bariam(Ba),uranium(U),arsenic(As),and rare earth elements(REE)in abundance.High uranium/thorium(U/Th)ratios(U/Th>1)indicated that mineralization was mainly influenced by the hydrothermal process.The δU value Was above 1.9.showing a reducing sedimentary condition.The REE patterns showed high enrichment in Iight rare earth elements (LREE)(heavy rare earth elements (HREE)(LREE/HREE=5-17),slightly negative europium(EU)and cerium(Ce)anomalies(δEu=0.81-0.93).and positive Ce anomalies(δCe=0.76-1.12).PGE abundance was characterized by the PGE-type distribution patterns,enriching platinum(Pt),palladium(Pd),ruthenium(RuJ and osmium(Os).The Pt,Pd ratio was 0.8.which is close to the ratios of seawater and ultramafic rocks.AII of these geochemical features suggest that the mineralization was triggered by hydrothermal activity in an extensionai setting in the context of break-up of the Rodinian supercontinent.

  13. Pharmacogenomics of platinum-based chemotherapy sensitivity in NSCLC: toward precision medicine.

    Science.gov (United States)

    Yin, Ji-Ye; Li, Xi; Zhou, Hong-Hao; Liu, Zhao-Qian

    2016-08-01

    Lung cancer is one of the leading causes of cancer-related death in the world. Platinum-based chemotherapy is the first-line treatment for non-small-cell lung cancer (NSCLC), however, the therapeutic efficiency varies remarkably among individuals. A large number of pharmacogenomics studies aimed to identify genetic variations which can be used to predict platinum response. Those studies are leading NSCLC treatment to the new era of precision medicine. In the current review, we provided a comprehensive update on the main recent findings of genetic variations which can be used to predict platinum sensitivity in the NSCLC patients.

  14. 从铂钯精矿中回收Au、Pt、Pd%Recovery of Gold, Platinum and Palladium From Platinum-Palladium Concentrate

    Institute of Scientific and Technical Information of China (English)

    王靖坤; 汪云华; 赵家春; 吴晓峰; 李博捷; 昝林寒; 范兴祥

    2012-01-01

    以某冶炼厂铜阳极泥处理过程中产生的铂钯精矿为原料,采用氯化浸出—亚硫酸钠还原分金—氯化铵沉铂—氨水沉钯湿法处理工艺回收Au、Pt、Pd.结果表明,工艺运行稳定,所得海绵钯、海绵铂纯度均大于99.95%,总收率大于98%.

  15. Novel platinum–palladium bimetallic nanoparticles synthesized by Dioscorea bulbifera: anticancer and antioxidant activities

    Directory of Open Access Journals (Sweden)

    Ghosh S

    2015-12-01

    Full Text Available Sougata Ghosh,1 Rahul Nitnavare,1 Ankush Dewle,1 Geetanjali B Tomar,1 Rohan Chippalkatti,1 Piyush More,1 Rohini Kitture,2 Sangeeta Kale,2 Jayesh Bellare,3 Balu A Chopade4 1Institute of Bioinformatics and Biotechnology, University of Pune, 2Department of Applied Physics, Defense Institute of Advanced Technology, Pune, 3Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, 4Department of Microbiology, University of Pune, Pune, India Abstract: Medicinal plants serve as rich sources of diverse bioactive phytochemicals that might even take part in bioreduction and stabilization of phytogenic nanoparticles with immense therapeutic properties. Herein, we report for the first time the rapid efficient synthesis of novel platinum–palladium bimetallic nanoparticles (Pt–PdNPs along with individual platinum (PtNPs and palladium (PdNPs nanoparticles using a medicinal plant, Dioscorea bulbifera tuber extract (DBTE. High-resolution transmission electron microscopy revealed monodispersed PtNPs of size 2–5 nm, while PdNPs and Pt–PdNPs between 10 and 25 nm. Energy dispersive spectroscopy analysis confirmed 30.88%±1.73% elemental Pt and 68.96%±1.48% elemental Pd in the bimetallic nanoparticles. Fourier transform infrared spectra indicated strong peaks at 3,373 cm-1, attributed to hydroxyl group of polyphenolic compounds in DBTE that might play a key role in bioreduction in addition to the sharp peaks at 2,937, 1,647, 1,518, and 1,024 cm-1, associated with C–H stretching, N–H bending in primary amines, N–O stretching in nitro group, and C–C stretch, respectively. Anticancer activity against HeLa cells showed that Pt–PdNPs exhibited more pronounced cell death of 74.25% compared to individual PtNPs (12.6% or PdNPs (33.15%. Further, Pt–PdNPs showed an enhanced scavenging activity against 2,2-diphenyl-1-picrylhydrazyl, superoxide, nitric oxide, and hydroxyl radicals. Keywords: Dioscorea bulbifera, platinum nanoparticles

  16. Preparation of platinum/iridium scanning probe microscopy tips

    DEFF Research Database (Denmark)

    Sørensen, Alexis Hammer; Hvid, U.; Mortensen, M.W.

    1999-01-01

    for the production of sharp tips. After being etched the tips are ready for use in scanning tunneling microscopes, or they may be bent to form integrated tip/cantilever systems in ordinary commercial atomic force microscopes, being applicable as tapping mode tips and as electrostatic force microscopy tips. ©1999......We report on the development of an etching setup for use in the preparation of platinum/iridium tips for atomic force microscopy and scanning electrostatic force microscopy as well as scanning tunneling microscopy. The etching process is based on a two step electrochemical procedure. The first step....... This mechanism is based on the formation of oxygen and hydrogen at the platinum/iridium electrode when the potential is above the dissociation potential of water (~ 1.23 V) and storage of these products interstitially in the outer layers of the platinum wire. This leads to "microexplosions" that detach fragments...

  17. Palladium catalysis for energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Pfefferle, L. D.; Datye, Abhaya

    2001-03-01

    Palladium (Pd) is an attractive catalyst for a range of new combustion applications comprising primary new technologies for future industrial energy needs, including gas turbine catalytic combustion, auto exhaust catalysts, heating and fuel cells. Pd poses particular challenges because it changes both chemical state and morphology as a function of temperature and reactant environment and those changes result in positive and negative changes in activity. Interactions with the support, additives, water, and contaminants as well as carbon formation have also been observed to affect Pd catalyst performance. This report describes the results of a 3.5 year project that resolves some of the conflicting reports in the literature about the performance of Pd-based catalysis.

  18. Palladium-mediated intracellular chemistry

    Science.gov (United States)

    Yusop, Rahimi M.; Unciti-Broceta, Asier; Johansson, Emma M. V.; Sánchez-Martín, Rosario M.; Bradley, Mark

    2011-03-01

    Many important intracellular biochemical reactions are modulated by transition metals, typically in the form of metalloproteins. The ability to carry out selective transformations inside a cell would allow researchers to manipulate or interrogate innumerable biological processes. Here, we show that palladium nanoparticles trapped within polystyrene microspheres can enter cells and mediate a variety of Pd0-catalysed reactions, such as allylcarbamate cleavage and Suzuki-Miyaura cross-coupling. The work provides the basis for the customization of heterogeneous unnatural catalysts as tools to carry out artificial chemistries within cells. Such in cellulo synthesis has potential for a plethora of applications ranging from cellular labelling to synthesis of modulators or inhibitors of cell function.

  19. Flow Injection Analysis with Electrochemical Detection for Rapid Identification of Platinum-Based Cytostatics and Platinum Chlorides in Water

    Directory of Open Access Journals (Sweden)

    Marketa Kominkova

    2014-02-01

    Full Text Available Platinum-based cytostatics, such as cisplatin, carboplatin or oxaliplatin are widely used agents in the treatment of various types of tumors. Large amounts of these drugs are excreted through the urine of patients into wastewaters in unmetabolised forms. This phenomenon leads to increased amounts of platinum ions in the water environment. The impacts of these pollutants on the water ecosystem are not sufficiently investigated as well as their content in water sources. In order to facilitate the detection of various types of platinum, we have developed a new, rapid, screening flow injection analysis method with electrochemical detection (FIA-ED. Our method, based on monitoring of the changes in electrochemical behavior of analytes, maintained by various pH buffers (Britton-Robinson and phosphate buffer and potential changes (1,000, 1,100 and 1,200 mV offers rapid and cheap selective determination of platinum-based cytostatics and platinum chlorides, which can also be present as contaminants in water environments.

  20. Flow injection analysis with electrochemical detection for rapid identification of platinum-based cytostatics and platinum chlorides in water.

    Science.gov (United States)

    Kominkova, Marketa; Heger, Zbynek; Zitka, Ondrej; Kynicky, Jindrich; Pohanka, Miroslav; Beklova, Miroslava; Adam, Vojtech; Kizek, Rene

    2014-02-04

    Platinum-based cytostatics, such as cisplatin, carboplatin or oxaliplatin are widely used agents in the treatment of various types of tumors. Large amounts of these drugs are excreted through the urine of patients into wastewaters in unmetabolised forms. This phenomenon leads to increased amounts of platinum ions in the water environment. The impacts of these pollutants on the water ecosystem are not sufficiently investigated as well as their content in water sources. In order to facilitate the detection of various types of platinum, we have developed a new, rapid, screening flow injection analysis method with electrochemical detection (FIA-ED). Our method, based on monitoring of the changes in electrochemical behavior of analytes, maintained by various pH buffers (Britton-Robinson and phosphate buffer) and potential changes (1,000, 1,100 and 1,200 mV) offers rapid and cheap selective determination of platinum-based cytostatics and platinum chlorides, which can also be present as contaminants in water environments.

  1. Palladium catalyzed hydrogenation of bio-oils and organic compounds

    Science.gov (United States)

    Elliott, Douglas C.; Hu, Jianli; Hart, Todd R.; Neuenschwander, Gary G.

    2008-09-16

    The invention provides palladium-catalyzed hydrogenations of bio-oils and certain organic compounds. Experimental results have shown unexpected and superior results for palladium-catalyzed hydrogenations of organic compounds typically found in bio-oils.

  2. 胶体钯基体改进剂对石墨炉原子吸收光谱法测定尿中的铅的应用研究%Research of application colloid palladium matrix modifier that determination of lead in urine uesing graphite furnace atomic absorption spectrometry

    Institute of Scientific and Technical Information of China (English)

    劳哲; 江恩源; 韦丽丽

    2015-01-01

    Objective Using graphite furnace atomic absorption spectrometry determination of lead in urine directly.Methods Select 1211 Workers morning urine, by graphite furnace atomic absorption spectrometer, colloid palladium alcohol aqueous solution was used as matrix modifier, to do determinetion.Results In all 1121 urine samples , has 32 cace more than 0.58 u mol/L GB of index.Conclusions This method with less background interference, high precision and accuracy, urine does not need pretreatment and dilution, can be directly determined.%目的:使用石墨炉原子吸收光谱法直接测定尿中铅的检测方法。方法:选取1211份梧州市的2间工厂的操作工人的晨尿样品,采用塞曼扣背景的石墨炉原子吸收光谱仪器,使用胶体钯醇水溶液作为基体改进剂进行测定。结果:在全部1121份尿样品之中有32份超过0.58μm o l/L的国标尿中铅轻度中毒指标。结论:本法背景干扰少,精密度和准确度高,尿样不需经过前处理和稀释就可以直接测定。

  3. Cross-reactivity of Halogenated Platinum Salts

    Science.gov (United States)

    Halogenated platinum (Pt) salts are well-known respiratory sensitizers associated with the development of asthma. People may be exposed to a variety of platinum compounds in different contexts (e.g. occupationally, automobile exhaust). Published reports suggest that sensitizati...

  4. Palladium-cobalt particles as oxygen-reduction electrocatalysts

    Science.gov (United States)

    Adzic, Radoslav; Huang, Tao

    2009-12-15

    The present invention relates to palladium-cobalt particles useful as oxygen-reducing electrocatalysts. The invention also relates to oxygen-reducing cathodes and fuel cells containing these palladium-cobalt particles. The invention additionally relates to methods for the production of electrical energy by using the palladium-cobalt particles of the invention.

  5. Progress of Palladium Alloy Membranes in Hydrogen Energy

    Institute of Scientific and Technical Information of China (English)

    MA Guang; LI Jin; LI Yin'e; SUN Xiaoliang; CAO Qigao; JIA Zhihua

    2012-01-01

    Palladium and palladium alloy membranes have attracted wide attention in hydrogen permeation areas for their excellent permeability,perm-selectivity and thermal stability.This paper review the principle of hydrogen permeation,type of alloys and the fabrication methods.At last,the progress and achievements on palladium alloy membranes by Northwest Institute for Non-Ferrous Metal Research are emphasized.

  6. Unexpectedly high uptake of palladium by bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos, J. [Research Lab. for Mining Chemistry, Hungarian Academy of Sciences, Miskolc-Egyetemvaros (Hungary); Brown, S.D.; Snape, C.E. [Univ. of Strathclyde, Dept. of Pure and Applied Chemistry, Glasgow (United Kingdom)

    1997-12-31

    The uptake of palladium as a conversion catalyst onto coals of different rank was investigated. Palladium fixation occurs by a different mode to that for alkaline earth and first row transition metals. Therefore, the dispersion of relatively high concentration of palladium by an ion sorption process is even possible for bituminous coals. (orig.)

  7. Synthesis of honeycomb-like palladium nanostructures by using cucurbit[7]uril and their catalytic activities for reduction of 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Premkumar, Thathan [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of); The University College/Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Geckeler, Kurt E., E-mail: keg@gist.ac.kr [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of); Department of Nanobio Materials and Electronics (WCU), Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2014-12-15

    An eco-friendly one-pot method to synthesize self-assembled palladium nanoclusters using a macrocycle, namely cucurbit[7]uril, in the alkaline medium without employing any special reducing or capping agents and/or external energy at room temperature is described. This greener approach, which utilizes water as a benign solvent and biocompatible cucurbit[7]uril as both reducing and protecting agents, can be applied to synthesize other noble metal nanoparticles such as gold, silver, and platinum. Owing to unique structural arrangement of cucurbit[7]uril, it was possible to prepare palladium nanoclusters of honeycomb-like structure irrespective of the reaction conditions. The honeycomb-like palladium nanoclusters were characterized using transmission electron microscopy (TEM), higher-resolution TEM (HR-TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV–vis, and FT-IR spectroscopy. Significantly, the synthesized palladium nanoclusters exhibited catalytic activity for the reduction reaction of 4-nitrophenol at room temperature. The approach launched here is easy, green, and user-friendly in contrast to the conventional techniques using polymers or surfactants and harsh reductants. - Highlights: • A simple and one-pot method to synthesis palladium nanostructures with honey-comb like structure. • The strategy established here does not require any harsh and toxic reducing agents. • It has a potential to be a general method for the synthesis of metal nanoparticles in water medium. • Palladium nanoclusters can be used as catalyst for the reduction reaction of 4-nitrophenol. • This system makes a novel platform for industrial and biomedical applications.

  8. Minitab软件确定电镀镍钯金引线框架银胶扩散因素%Determination of factors on epoxy bleed out from nickel/palladium/gold plated lead frame by Minitab software

    Institute of Scientific and Technical Information of China (English)

    马明明; 同帜; 席小云; 刘波涛

    2011-01-01

    电镀镍钯金引线框架工艺流程繁琐,所用的导电银胶在其每一个工艺步骤都有可能使引线发生银胶扩散现象,导致产品报废.为了减少实验盲目性和不必要的经济损失,采用Minitab软件中的Plackett-Burman设计方法,对可能影响电镀镍钯金引线框架银胶扩散的20个工艺因素进行筛选,得出钯厚度、镍厚度、镀金占空比、钯比重、镀镍后酸洗盐酸体积分数和钯含量为影响银胶扩散的主要工艺参数.运用Minitab软件的田1:7方法优化了上述6个工艺参数,得到最佳工艺值分别是:钯厚度0.8 mil,镍厚度40 mil,镀金占空比0.65,镀钯液比重10.5,后酸洗盐酸体积分数0.125,钯缸中钯含量5.0 g/L.单样本T方法验证的结果令人满意.%The plating procedure of Ni/Pd/Au lead frame is complicated. The products may discarded due to the bleed out of conductive epoxy in every possible step. Twenty factors which may affect epoxy bleed out in plating of Ni/Pa/Au lead frame were studied based on Plackett-Burman design by using the Minitab software to eliminate blindness in experiments and unnecessary economic loss. Six factors were screened out as the main process parameters and optimized by Taguchi method as follows: Pd coating thickness 0.8 mil, Ni coating thickness 40 mil, duty cycle in Au plating 0.65, specific weight of Pd plating solution 10.5, volume fraction of hydrochloric acid 0.125 for pickling after nickel plating, and Pd content in Pd plating bath 5.0 g/L. The results of one-sample T test for verification were satisfactory.

  9. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

  10. Luminescent liquid crystalline materials based on palladium(II) imine derivatives containing the 2-phenylpyridine core.

    Science.gov (United States)

    Micutz, Marin; Iliş, Monica; Staicu, Teodora; Dumitraşcu, Florea; Pasuk, Iuliana; Molard, Yann; Roisnel, Thierry; Cîrcu, Viorel

    2014-01-21

    In this work we report our studies concerning the synthesis and characterisation of a series of imine derivatives that incorporate the 2-phenylpyridine (2-ppy) core. These derivatives were used in the cyclometalating reactions of platinum(II) or palladium(II) in order to prepare several complexes with liquid crystalline properties. Depending on the starting materials used as well as the solvents employed, different metal complexes were obtained, some of them showing both liquid crystalline behaviour and luminescence properties at room temperature. It was found that, even if there are two competing coordination sites, the cyclometalation process takes place always at the 2-ppy core with (for Pt) or without (for Pd) the imine bond cleavage. We successfully showed that it is possible to prepare emissive room temperature liquid crystalline materials based on double cyclopalladated heteroleptic complexes by varying the volume fraction of the long flexible alkyl tails on the ancillary benzoylthiourea (BTU) ligands.

  11. Gold and palladium adsorption from leached electronic scrap using ordered mesoporous carbon nanoscaffolds

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, Rocklan; Dutech, Guy

    2014-09-01

    Ordered mesoporous carbon (OMC) nanoscaffolds are engineered agglomerates of carbon nanotubes held together by small carbon nanofibers with uniform pore sizes, high pore volume, and high channel permeability. These materials exhibit very high affinity for the adsorption of gold from aqueous acidic mixtures. The efficiency of gold recovery is comparable to those typically accomplished using biopolymer-based adsorbents. The adsorption efficiency for other precious metals such as palladium and platinum is lower. Studies on the precious metal (Au, Pd) adsorption on OMC materials from actual liquors of leached electronics will be presented. Adsorption properties will be compared for several different sorbents used for the recovery of precious metals. The leach liquor compositions for three different types of electronic scrap materials (personal computer board, cell phone and tv input/output board) will be presented. The sorption efficiencies for Au, Pd, together with a spectrum of competing and non-competing metals, from such leach mixtures will be compared.

  12. Decomposition of the Precursor [Pt(NH3)4](OH)2, Genesis and Structure of the Metal-Support Interface of Alumina Supported Platinum Particles: A Structural Study Using TPR, MS and XAFS Spectroscopy.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Muñoz-Paez, A.

    1995-01-01

    During the preparation of alumina supported platinum catalysts, the precursor [Pt(NH3)4](OH)2 decomposes to a neutral Pt(NH3)zO species during the drying process at 120 'C. Treatment in flowing hydrogen at 180 'C leads to partial reduction of the platinum ammine complex and formation of platinum met

  13. 同位素稀释-ICPMS法测定地质标准物质中铂族元素%Determination of Platinum-group Elements in the Geological Standard Reference Materials by Isotope Dilution-ICPMS

    Institute of Scientific and Technical Information of China (English)

    胡明月; 何红蓼

    2005-01-01

    Platinum group elements (PGEs) includes platinum, palladium, iridium, osmium, rhodium and ruthenium. It has very high economic and scientific value in the field of geoscience and environmental science. But the analysis data referred by the different lab are very disperse because of the difficulty of the determination of PGEs. It makes very difficult to fix the value of the PGEs in the standard reference materials. In the article, the values of the PGEs in the standard reference materials of ocean sediment are determined by isotope dilution technique and dependable values of these elements are provided.

  14. Platinum Group Metals New Material

    Institute of Scientific and Technical Information of China (English)

    XIE Ming; ZHANG Jiankang; WANG Saibei; HU Jieqiong; LIU Manmen; CHEN Yongtai; ZHANG Jiming; YANG Youcai; YANG Yunfeng; ZHANG Guoquan

    2012-01-01

    Platinum group metals (PGM) include six elements,namely Pt,Pd,Rh,Ir,Os and Ru.PGM and their alloys are the important fundamental materials for modern industry and national defense construction,they have special physical and chemical properties,widely used in metallurgy,chemical,electric,electronic,information,energy,environmental protection,aviation,aerospace,navigation and other high technology industry.Platinum group metals and their alloys,which have good plasticity and processability,can be processed to electrical contact materials,resistance materials,solder,electronic paste,temperature-measurement materials,elastic materials,magnetic materials and high temperature structural materials.

  15. X-ray characterization of platinum group metal catalysts

    Science.gov (United States)

    Peterson, Eric J.

    Platinum group metals (PGMs) are used extensively as catalysts, employed in several sectors of the world energy economy. Fuel cells employing PGM catalysts show promise as power sources in the proposed hydrogen economy, using alcohols as hydrogen storage media. Currently, the most economically important application for PGMs is for the mitigation of emissions from internal combustion engines via catalytic converters. In all applications, efficient use of these expensive metals to fabricate robust catalysts is of the utmost importance. Understanding the catalyst structure/property relationship is the key to the improvement of existing catalysts and the discovery of new catalysts. For example, catalyst particle size can have profound effects on catalyst activity, as in the case of gold nanoparticles. Catalyst particle size control and stability is also important for the efficient use of PGM metals and catalyst deactivation prevention. The challenge is to identify and characterize structural features and determine if and how these features may relate to catalytic properties. The ultimate goal is to simultaneously measure catalyst structural characteristics and catalytic properties under operando conditions, unambiguously establishing the structure/property link. X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are important techniques used for the characterization of PGM catalysts. Microstructural information such as crystallite size, as small as ~ 1 nm, and microstrain can be obtained from Bragg diffraction peak shapes in X-ray diffraction patterns, and long range crystal structure information is found in the intensities and positions of these peaks. In contrast, X-ray absorption spectroscopy provides information about the chemical state and local structure of selected atoms. From the average nearest neighbor coordination numbers, crystallite sizes can also be inferred, with particularly high sensitivity in the sub-nm size range. Electron microscopy

  16. Ageing of palladium tritide: mechanical characterization, helium state and modelling; Vieillissement du tritiure de palladium: caracterisation mecanique, etat de l'helium et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Segard, M.

    2010-11-29

    Palladium is commonly used for the storage of tritium (the hydrogen radioactive isotope), since it forms a low-equilibrium-pressure and reversible tritide. Tritium decay into helium-3 is responsible for the ageing of the tritide, leading to the apparition of helium-3 bubbles for instance. Both experimental and theoretical aspects of this phenomenon are studied here.Previous works on ageing modelling led to two main models, dealing with:- Helium-3 bubbles nucleation (using a cellular automaton), - Bubbles growth (using continuum mechanics).These models were quite efficient, but their use was limited by the lack of input data and fitting experimental parameters.To get through these limitations, this work has consisted in studying the most relevant experimental data to improve the modelling of the palladium tritide ageing.The first part of this work was focused on the assessment of the mechanical properties of the palladium tritide (yield strength, ultimate strength, mechanical behaviour). They were deduced from the in situ tensile tests performed on palladium hydride and deuteride. In the second part, ageing characterization was undertaken, mainly focusing on: - Bubbles observations in palladium tritide using transmission electron microscopy, - Internal bubble pressure measurements using nuclear magnetic resonance, - Macroscopic swelling measurements using pycno-metry.The present work has led to significant progress in ageing understanding and has brought very valuable improvements to the modelling of such a phenomenon. (author) [French] Le palladium est couramment utilise pour le stockage du tritium, isotope radioactif de l'hydrogEne, car il forme un tritiure reversible, A basse pression d'equilibre. La decroissance du tritium en helium-3 provoque un vieillissement du tritiure, caracterise notamment par l'apparition de bulles d'helium-3, qui est etudie ici. De precedents travaux de modelisation du vieillissement avaient abouti a la creation de

  17. Silver-Palladium Surfaces Inhibit Biofilm Formation

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Schroll, Casper; Hilbert, Lisbeth Rischel

    2009-01-01

    Undesired biofilm formation is a major concern in many areas. In the present study, we investigated biofilm-inhibiting properties of a silver-palladium surface that kills bacteria by generating microelectric fields and electrochemical redox processes. For evaluation of the biofilm inhibition...... efficacy and study of the biofilm inhibition mechanism, the silver-sensitive Escherichia coli J53 and the silver-resistant E. coli J53[pMG101] strains were used as model organisms, and batch and flow chamber setups were used as model systems. In the case of the silver-sensitive strain, the silver......-palladium surfaces killed the bacteria and prevented biofilm formation under conditions of low or high bacterial load. In the case of the silver-resistant strain, the silver-palladium surfaces killed surface-associated bacteria and prevented biofilm formation under conditions of low bacterial load, whereas under...

  18. Californium Recovery from Palladium Wire

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Jon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-08-01

    The recovery of 252Cf from palladium-252Cf cermet wires was investigated to determine the feasibility of implementing it into the cermet wire production operation at Oak Ridge National Laboratory’s Radiochemical Engineering Development Center. The dissolution of Pd wire in 8 M HNO3 and trace amounts of HCl was studied at both ambient and elevated temperatures. These studies showed that it took days to dissolve the wire at ambient temperature and only 2 hours at 60°C. Adjusting the ratio of the volume of solvent to the mass of the wire segment showed little change in the kinetics of dissolution, which ranged from 0.176 mL/mg down to 0.019 mL/mg. A successful chromatographic separation of 153Gd, a surrogate for 252Cf, from Pd was demonstrated using AG 50x8 cation exchange resin with a bed volume of 0.5 mL and an internal diameter of 0.8 cm.

  19. Californium Recovery from Palladium Wire

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Jon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-08-01

    The recovery of 252Cf from palladium-252Cf cermet wires was investigated to determine the feasibility of implementing it into the cermet wire production operation at Oak Ridge National Laboratory’s Radiochemical Engineering Development Center. The dissolution of Pd wire in 8 M HNO3 and trace amounts of HCl was studied at both ambient and elevated temperatures. These studies showed that it took days to dissolve the wire at ambient temperature and only 2 hours at 60°C. Adjusting the ratio of the volume of solvent to the mass of the wire segment showed little change in the kinetics of dissolution, which ranged from 0.176 mL/mg down to 0.019 mL/mg. A successful chromatographic separation of 153Gd, a surrogate for 252Cf, from Pd was demonstrated using AG 50x8 cation exchange resin with a bed volume of 0.5 mL and an internal diameter of 0.8 cm.

  20. Nanocarriers for delivery of platinum anticancer drugs☆

    Science.gov (United States)

    Oberoi, Hardeep S.; Nukolova, Natalia V.; Kabanov, Alexander V.; Bronich, Tatiana K.

    2014-01-01

    Platinum based anticancer drugs have revolutionized cancer chemotherapy, and continue to be in widespread clinical use especially for management of tumors of the ovary, testes, and the head and neck. However, several dose limiting toxicities associated with platinum drug use, partial anti-tumor response in most patients, development of drug resistance, tumor relapse, and many other challenges have severely limited the patient quality of life. These limitations have motivated an extensive research effort towards development of new strategies for improving platinum therapy. Nanocarrier-based delivery of platinum compounds is one such area of intense research effort beginning to provide encouraging preclinical and clinical results and may allow the development of the next generation of platinum chemotherapy. This review highlights current understanding on the pharmacology and limitations of platinum compounds in clinical use, and provides a comprehensive analysis of various platinum–polymer complexes, micelles, dendrimers, liposomes and other nanoparticles currently under investigation for delivery of platinum drugs. PMID:24113520

  1. Palladium nanoparticles obtained by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Sampedro, B.; Hernando, A. [Instituto de Magnetismo Aplicado (RENFE-UCM-CSIC), P.O. Box 155, 28230 Las Rozas, Madrid (Spain); Dpto. Fisica de Materiales, UCM, 28040 Madrid (Spain); Rojas, T.C.; Fernandez, A. [Instituto de Ciencia de Materiales de Sevilla, Centro mixto CSIC-UNIV, 41092 Sevilla (Spain)

    2006-05-15

    Opposed to the existing chemical methods, we have used a physical one in order to obtain palladium nanoparticles. In this work we present the HRTEM observation of Pd nanoparticles obtained by mechanical milling. These particles are around 6 nm in size. The Pd milled samples have exhaustively been structurally characterized. We have also studied its magnetic properties as a function of the milling time and magnetic measurements are according to those previously carried out by us in palladium nanoparticles obtained by chemical methods. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Highly Concentrated Palladium Hydrides/Deuterides; Theory

    Energy Technology Data Exchange (ETDEWEB)

    Papaconstantopoulos, Dimitrios

    2013-11-26

    Accomplishments are reported in these areas: tight-binding molecular dynamics study of palladium; First-principles calculations and tight-binding molecular dynamics simulations of the palladium-hydrogen system; tight-binding studies of bulk properties and hydrogen vacancies in KBH{sub 4}; tight-binding study of boron structures; development of angular dependent potentials for Pd-H; and density functional and tight-binding calculations for the light-hydrides NaAlH4 and NaBH4

  3. [Formylation of porphyrin platinum complexes].

    Science.gov (United States)

    Rumiantseva, V D; Konovalenko, L I; Nagaeva, E A; Mironov, A F

    2005-01-01

    The formylation reaction of platinum complexes of beta-unsubstituted porphyrins was studied. The interaction of deuteroporphyrin IX derivatives with the Vilsmeyer reagent led to the selective formylation of their macrocycles in the beta position. The resulting formyl derivatives of the porphyrins are of interest for fluorescent immunoassay.

  4. Palladium-Catalyzed Intramolecular Aminofluorination of Styrenes%Palladium-Catalyzed Intramolecular Aminofluorination of Styrenes

    Institute of Scientific and Technical Information of China (English)

    徐涛; 邱水发; 刘国生

    2011-01-01

    A novel palladium-catalyzed intramolecular oxidative aminofluorination of styrenes has been developed by using NFSI as fluorinating reagent. This reaction represented an efficient method for the synthesis of 2-aryl-3-fluoropyrrolidine derivatives.

  5. Cytotoxic properties of a new organometallic platinum(II) complex and its gold(I) heterobimetallic derivatives.

    Science.gov (United States)

    Serratrice, Maria; Maiore, Laura; Zucca, Antonio; Stoccoro, Sergio; Landini, Ida; Mini, Enrico; Massai, Lara; Ferraro, Giarita; Merlino, Antonello; Messori, Luigi; Cinellu, Maria Agostina

    2016-01-14

    A novel platinum(ii) organometallic complex, [Pt(pbi)(Me)(DMSO)], bearing the 2-(2'-pyridyl)-benzimidazole (pbiH) ligand, was synthesized and fully characterized. Interestingly, the reaction of this organometallic platinum(ii) complex with two distinct gold(i) phosphane compounds afforded the corresponding heterobimetallic derivatives with the pbi ligand bridging the two metal centers. The antiproliferative properties in vitro of [Pt(pbi)(Me)(DMSO)] and its gold(i) derivatives as well as those of the known coordination platinum(ii) and palladium(ii) complexes with the same ligand, of the general formula [MCl2(pbiH)], were comparatively evaluated against A2780 cancer cells, either sensitive or resistant to cisplatin. A superior biological activity of the organometallic compound clearly emerged compared to the corresponding platinum(ii) complex; the antiproliferative effects are further enhanced upon attaching the gold(i) triphenylphosphine moiety to the organometallic Pt compound. Remarkably, these novel metal species are able to overcome nearly complete resistance to cisplatin. Significant mechanistic insight into the study compounds was gained after investigating their reactions with a few representative biomolecules by electrospray mass spectrometry and X-ray crystallography. The obtained results are comprehensively discussed.

  6. Formation of palladium(0) nanoparticles at microbial surfaces.

    Science.gov (United States)

    Bunge, Michael; Søbjerg, Lina S; Rotaru, Amelia-Elena; Gauthier, Delphine; Lindhardt, Anders T; Hause, Gerd; Finster, Kai; Kingshott, Peter; Skrydstrup, Troels; Meyer, Rikke L

    2010-10-01

    The increasing demand and limited natural resources for industrially important platinum-group metal (PGM) catalysts render the recovery from secondary sources such as industrial waste economically interesting. In the process of palladium (Pd) recovery, microorganisms have revealed a strong potential. Hitherto, bacteria with the property of dissimilatory metal reduction have been in focus, although the biochemical reactions linking enzymatic Pd(II) reduction and Pd(0) deposition have not yet been identified. In this study we investigated Pd(II) reduction with formate as the electron donor in the presence of Gram-negative bacteria with no documented capacity for reducing metals for energy production: Cupriavidus necator, Pseudomonas putida, and Paracoccus denitrificans. Only large and close-packed Pd(0) aggregates were formed in cell-free buffer solutions. Pd(II) reduction in the presence of bacteria resulted in smaller, well-suspended Pd(0) particles that were associated with the cells (called "bioPd(0)" in the following). Nanosize Pd(0) particles (3-30 nm) were only observed in the presence of bacteria, and particles in this size range were located in the periplasmic space. Pd(0) nanoparticles were still deposited on autoclaved cells of C. necator that had no hydrogenase activity, suggesting a hydrogenase-independent formation mechanism. The catalytic properties of Pd(0) and bioPd(0) were determined by the amount of hydrogen released in a reaction with hypophosphite. Generally, bioPd(0) demonstrated a lower level of activity than the Pd(0) control, possibly due to the inaccessibility of the Pd(0) fraction embedded in the cell envelope. Our results demonstrate the suitability of bacterial cells for the recovery of Pd(0), and formation and immobilization of Pd(0) nanoparticles inside the cell envelope. However, procedures to make periplasmic Pd(0) catalytically accessible need to be developed for future nanobiotechnological applications.

  7. High Performance Palladium Supported on Nanoporous Carbon under Anhydrous Condition

    Science.gov (United States)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Xu, Guodong

    2016-11-01

    Due to the high cost of polymer electrolyte fuel cells (PEFCs), replacing platinum (Pt) with some inexpensive metal was carried out. Here, we deposited palladium nanoparticles (Pd-NPs) on nanoporous carbon (NC) after wrapping by poly[2,2‧-(2,6-pyridine)-5,5‧-bibenzimidazole] (PyPBI) doped with phosphoric acid (PA) and the Pd-NPs size was successfully controlled by varying the weight ratio between Pd precursor and carbon support doped with PA. The membrane electrode assembly (MEA) fabricated from the optimized electrocatalyst with 0.05 mgPd cm‑2 for both anode and cathode sides showed a power density of 76 mW cm‑2 under 120 °C without any humidification, which was comparable to the commercial CB/Pt, 89 mW cm‑2 with 0.45 mgPt cm‑2 loaded in both anode and cathode. Meanwhile, the power density of hybrid MEA with 0.45 mgPt cm‑2 in cathode and 0.05 mgPd cm‑2 in anode reached 188 mW cm‑2. The high performance of the Pt-free electrocatalyst was attributed to the porous structure enhancing the gas diffusion and the PyPBI-PA facilitating the proton conductivity in catalyst layer. Meanwhile, the durability of Pd electrocatalyst was enhanced by coating with acidic polymer. The newly fabricated Pt-free electrocatalyst is extremely promising for reducing the cost in the high-temperature PEFCs.

  8. Viral-templated Palladium Nanocatalysts

    Science.gov (United States)

    Yang, Cuixian

    Despite recent progress on nanocatalysis, there exist several critical challenges in simple and readily controllable nanocatalyst synthesis including the unpredictable particle growth, deactivation of catalytic activity, cumbersome catalyst recovery and lack of in-situ reaction monitoring. In this dissertation, two novel approaches are presented for the fabrication of viral-templated palladium (Pd) nanocatalysts, and their catalytic activities for dichromate reduction reaction and Suzuki Coupling reaction were thoroughly studied. In the first approach, viral template based bottom-up assembly is employed for the Pd nanocatalyst synthesis in a chip-based format. Specifically, genetically displayed cysteine residues on each coat protein of Tobacco Mosaic Virus (TMV) templates provide precisely spaced thiol functionalities for readily controllable surface assembly and enhanced formation of catalytically active Pd nanoparticles. Catalysts with the chip-based format allow for simple separation and in-situ monitoring of the reaction extent. Thorough examination of synthesis-structure-activity relationship of Pd nanoparticles formed on surface-assembled viral templates shows that Pd nanoparticle size, catalyst loading density and catalytic activity of viral-templated Pd nanocatalysts can be readily controlled simply by tuning the synthesis conditions. The viral-templated Pd nanocatalysts with optimized synthesis conditions are shown to have higher catalytic activity per unit Pd mass than the commercial Pd/C catalysts. Furthermore, tunable and selective surface assembly of TMV biotemplates is exploited to control the loading density and location of Pd nanocatalysts on solid substrates via preferential electroless deposition. In addition, the catalytic activities of surface-assembled TMV-templated Pd nanocatalysts were also investigated for the ligand-free Suzuki Coupling reaction under mild reaction conditions. The chip-based format enables simple catalyst separation and

  9. Recovery of palladium, cesium, and selenium from heavy metal alkali borosilicate glass by combination of heat treatment and leaching processes

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhanglian; Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Nishimura, Fumihiro; Yonezawa, Susumu

    2017-06-05

    Highlights: • A separation technique of both noble and less noble metal from glass is studied. • Via reductive heat treatment, 80% of palladium is extracted in liquid bismuth. • Sodium–potassium-rich materials with cesium and selenium are phase separated. • From the materials, over 80% of cesium and selenium are extracted in water. - Abstract: Reductive heat-treatment and leaching process were applied to a simulated lead or bismuth soda-potash-borosilicate glass with palladium, cesium, and selenium to separate these elements. In the reductive heat treatment, palladium is extracted in liquid heavy metal phase generated by the reduction of the heavy metal oxides, whereas cesium and selenium are concentrated in phase separated Na–K-rich materials on the glass surface. From the materials, cesium and selenium can be extracted in water, and the selenium extraction was higher in the treatment of the bismuth containing glass. The chemical forms of palladium in the glass affected the extraction efficiencies of cesium and selenium. Among the examined conditions, in the bismuth glass treatment, the cesium and selenium extraction efficiencies in water were over 80%, and that of palladium in liquid bismuth was over 80%.

  10. Palladium-Catalyzed Asymmetric Quaternary Stereocenter Formation

    NARCIS (Netherlands)

    Gottumukkala, Aditya L.; Matcha, Kiran; Lutz, Martin; de Vries, Johannes G.; Minnaard, Adriaan J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of beta,beta-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and pr

  11. Palladium-catalyzed asymmetric quaternary stereocenter formation

    NARCIS (Netherlands)

    Gottumukkala, A.L.; Matcha, K.; Lutz, M.; de Vries, J.G.; Minnaard, A.J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and provides

  12. Palladium-catalyzed asymmetric quaternary stereocenter formation

    NARCIS (Netherlands)

    Gottumukkala, A.L.; Matcha, K.; Lutz, M.|info:eu-repo/dai/nl/304828971; de Vries, J.G.; Minnaard, A.J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and provides

  13. Clay Aerogel Supported Palladium Nanoparticles as Catalysts

    Directory of Open Access Journals (Sweden)

    Jared J. Griebel

    2016-04-01

    Full Text Available Highly porous, low density palladium nanoparticle/clay aerogel materials have been produced and demonstrated to possess significant catalytic activity for olefin hydrogenation and isomerization reactions at low/ambient pressures. This technology opens up a new route for the production of catalytic materials.

  14. Palladium-Catalyzed Asymmetric Quaternary Stereocenter Formation

    NARCIS (Netherlands)

    Gottumukkala, Aditya L.; Matcha, Kiran; Lutz, Martin; de Vries, Johannes G.; Minnaard, Adriaan J.

    2012-01-01

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of beta,beta-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and pr

  15. Homogeneous catalysis for the production of fine chemicals. Palladium- and nickel-catalysed aromatic carbon–carbon bond formation

    NARCIS (Netherlands)

    Tucker, Charles E.; Vries, Johannes G. de

    2002-01-01

    In this article we describe our recent efforts in the area of palladium- and nickel-catalysed aromatic substitution reactions. Main focus is on low cost and low waste production methods. The use of aromatic carboxylic anhydrides in the Heck reaction leads to a waste-free protocol. In addition these

  16. Palladium-catalyzed regioselective intramolecular coupling of o-carborane with aromatics via direct cage B-H activation.

    Science.gov (United States)

    Quan, Yangjian; Xie, Zuowei

    2015-03-18

    Palladium-catalyzed intramolecular coupling of o-carborane with aromatics via direct cage B-H bond activation has been achieved, leading to the synthesis of a series of o-carborane-functionalized aromatics in high yields with excellent regioselectivity. In addition, the site selectivity can also be tuned by the substituents on cage carbon atom.

  17. Oxygen Reduction on Platinum

    DEFF Research Database (Denmark)

    Nesselberger, Markus

    bands are observed on the Pt/C layer: bands arising from the functional groups of the carbon support, bands related to water and hydronium, and bands related to the sulfur anion interaction with the catalyst. The correlation of the anion absorption to the ORR current leads to the proposition that anion...

  18. Palladium urchin-like nanostructures and their H{sub 2} sorption properties

    Energy Technology Data Exchange (ETDEWEB)

    Ksar, F; Sharma, G K; Audonnet, F; Remita, H [Laboratoire de Chimie Physique, UMR 8000-CNRS, Batiment 349, Universite Paris-Sud, 91405 Orsay (France); Beaunier, P, E-mail: fabrice.audonnet@u-psud.fr, E-mail: hynd.remita@u-psud.fr [Laboratoire de Reactivite de Surface, UMR 7197-CNRS, UPMC Universite Paris 6, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

    2011-07-29

    Urchin-like palladium nanostructures were synthesized by slow radiolytic reduction of Pd{sup II} in cetylpyridinium chloride (CPCl) micellar solution. They were formed by polycrystalline nanowires originating from the same core. The growth process leading to these urchin-like structures has been studied. These three-dimensional (3D) nanostructures were obtained at high Pd concentration (0.1 M) which led to a relatively large quantity of nanomaterials. These nanostructures show very interesting cycling sorption properties for hydrogen storage.

  19. An Examination of the Surface and Sub-Surface of Modern and Historical Platinum Photographic Prints Using Low Vacuum High-Resolution Scanning Electron Microscopy.

    Science.gov (United States)

    Ravines, Patrick; Erdman, Natasha; McElroy, Rob

    2016-08-01

    Photographic prints of platinum metal on paper supports are some of the most exquisite and expressive in the world of fine art photography. Platinum prints were produced from about 1890 to 1920 in the USA and Europe. The chemical and material nature of these valuable prints is of great interest to many who are interested in their long-term preservation, in the intersection of science and art, and in the scientific and technical study of cultural heritage. This paper presents the results of a characterization study using newer electron microscopy techniques. In this study, a low vacuum high-resolution scanning electron microscope was used to study the surface and sub-surface of historic and modern platinum and/or palladium print samples. Using environmental SEM pressures allowed us to investigate the actual top surface and sub-surface with cross-sections without any preparation; no coatings of carbon or other material. Cross-sections were prepared using an argon plasma cross-polishing system. This study shows that the photographic image of platinum prints is composed of platinum nanoparticles embedded in the upper layers of the paper's cellulosic fibers.

  20. First platinum moderated positron beam based on neutron capture

    CERN Document Server

    Hugenschmidt, C; Repper, R; Schreckenbach, K; Sperr, P; Triftshaeuser, W

    2002-01-01

    A positron beam based on absorption of high energy prompt gamma-rays from thermal neutron capture in sup 1 sup 1 sup 3 Cd was installed at a neutron guide of the high flux reactor at the ILL in Grenoble. Measurements were performed for various source geometries, dependent on converter mass, moderator surface and extraction voltages. The results lead to an optimised design of the in-pile positron source which will be implemented at the Munich research reactor FRM-II. The positron source consists of platinum foils acting as gamma-e sup + e sup - -converter and positron moderator. Due to the negative positron work function moderation in heated platinum leads to emission of monoenergetic positrons. The positron work function of polycrystalline platinum was determined to 1.95(5) eV. After acceleration to several keV by four electrical lenses the beam was magnetically guided in a solenoid field of 7.5 mT leading to a NaI-detector in order to detect the 511 keV gamma-radiation of the annihilating positrons. The posi...

  1. Nanostructured silver and platinum modified carbon fiber microelectrodes coated with nafion for H2O2 determination

    Directory of Open Access Journals (Sweden)

    Vladimir Halouzka

    2010-12-01

    Full Text Available Carbon fiber microelectrodes equipped with nanostructured metals(platinum and silver and covered with a Nafion layer constitutesensitive H2O2 sensors. Metallic layers on carbon fibers wereprepared by surfactant assisted electrodeposition. In the case ofsilver, the procedure leads to coating which is composed of porous,partially aggregated and crystalline deposits containing silvernanoparticles. The electrodeposition of platinum leads to carbonfiber decorated with clusters of platinum nanoparticles. Aftercoating the electrodes with protective and antiinterference barriermade of Nafion, the sensing properties of the preparedmicroelectrodes towards hydrogen peroxide are investigated.

  2. Palladium and platinum complexes of 2-(2'-carboxyphenylazo)-4 methylphenol: Synthesis, structure and spectral properties

    Indian Academy of Sciences (India)

    Sarmistha Halder; Michael G B Drew; Samaresh Bhattacharya

    2008-09-01

    Reaction of 2-(2'-carboxyphenylazo)-4-methylphenol (H2L) with [M(PPh3)2Cl2] (M = Pd, Pt) affords mixed-ligand complexes of type [M(PPh3)(L)]. Structures of both the complexes have been determined by X-ray crystallography. Both the complexes are square planar, where the 2-(2'-carboxyphenylazo)-4-methylphenol is coordinated to the metal center, via dissociation of the two acidic protons, as a dianionic tridentate O,N,O-donor, and the fourth position is occupied by the triphenylphosphine. These complexes show intense MLCT transitions in the visible region.

  3. Palladium and platinum-based nanoparticle functional sensor layers for selective H2 sensing

    Energy Technology Data Exchange (ETDEWEB)

    Ohodnicki, Jr., Paul R.; Baltrus, John P.; Brown, Thomas D.

    2017-07-04

    The disclosure relates to a plasmon resonance-based method for H.sub.2 sensing in a gas stream utilizing a hydrogen sensing material. The hydrogen sensing material is comprises Pd-based or Pt-based nanoparticles having an average nanoparticle diameter of less than about 100 nanometers dispersed in an inert matrix having a bandgap greater than or equal to 5 eV, and an oxygen ion conductivity less than approximately 10.sup.-7 S/cm at a temperature of 700.degree. C. Exemplary inert matrix materials include SiO.sub.2, Al.sub.2O.sub.3, and Si.sub.3N.sub.4 as well as modifications to modify the effective refractive indices through combinations and/or doping of such materials. The hydrogen sensing material utilized in the method of this disclosure may be prepared using means known in the art for the production of nanoparticles dispersed within a supporting matrix including sol-gel based wet chemistry techniques, impregnation techniques, implantation techniques, sputtering techniques, and others.

  4. In situ TEM and STEM studies of reversible electromigration in thin palladium-platinum bridges

    Science.gov (United States)

    Kozlova, Tatiana; Rudneva, Maria; Zandbergen, Henny W.

    2013-12-01

    We investigated the reversible electromigration in Pd-Pt nanobridges by means of in situ electron microscopy. Real-time nanometer-scale imaging with scanning transmission electron microscopy was used to determine the material transport. For high current densities (3-5 × 107 A cm-2), material transport occurs from the cathode towards the anode side, indicating a negative effective charge. The electromigration is dominated by atom diffusion at grain boundaries on the free surface. The reversal of material transport upon a change of the electric field direction could be the basis of a memristor.

  5. Chemical modifiers in electrothermal atomic absorption determination of Platinum and Palladium containing preparations in blood serum

    Directory of Open Access Journals (Sweden)

    Аntonina Alemasova

    2012-11-01

    Full Text Available The biological liquids matrixes influence on the characteristic masses and repeatability of Pt and Pd electrothermal atomic absorption spectroscopy (ETAAS determination was studied. The chemical modifiers dimethylglyoxime and ascorbic acid for matrix interferences elimination and ETAAS results repeatability improvement were proposed while bioliquids ETAAS analysis, and their action mechanism was discussed.

  6. Electrocatalysis of formic acid on palladium and platinum surfaces: from fundamental mechanisms to fuel cell applications.

    Science.gov (United States)

    Jiang, Kun; Zhang, Han-Xuan; Zou, Shouzhong; Cai, Wen-Bin

    2014-10-14

    Formic acid as a natural biomass and a CO2 reduction product has attracted considerable interest in renewable energy exploitation, serving as both a promising candidate for chemical hydrogen storage material and a direct fuel for low temperature liquid fed fuel cells. In addition to its chemical dehydrogenation, formic acid oxidation (FAO) is a model reaction in the study of electrocatalysis of C1 molecules and the anode reaction in direct formic acid fuel cells (DFAFCs). Thanks to a deeper mechanistic understanding of FAO on Pt and Pd surfaces brought about by recent advances in the fundamental investigations, the "synthesis-by-design" concept has become a mainstream idea to attain high-performance Pt- and Pd-based nanocatalysts. As a result, a large number of efficient nanocatalysts have been obtained through different synthesis strategies by tailoring geometric and electronic structures of the two primary catalytic metals. In this paper, we provide a brief overview of recent progress in the mechanistic studies of FAO, the synthesis of novel Pd- and Pt-based nanocatalysts as well as their practical applications in DFAFCs with a focus on discussing studies significantly contributing to these areas in the past five years.

  7. Platinum and Palladium in Coal Rock and Geochemical Anomaly in Eastern Yunnan Province,Southwest China

    Institute of Scientific and Technical Information of China (English)

    Xia Qinglin; Zhao Pengda; Cheng Qiuming; Chen Yongqing; Zhang Shengyuan

    2008-01-01

    A series of geochemical anomalies of Pt and Pd were found in 1 358 recombined samples from a geochemical stream sediment survey in eastern Yunnan (云南) Province, China. Chemical optical emission spectroscopy, X-ray fluorescence analysis, and inductively coupled plasmas atomic emission spectrometry analyses of 22 elements and chemical compositions of 21 samples from coal-bearing strata from the Late Paleozoic, Mesozoic, and Cenozoic show Pt and Pd concentrated to some extent in coal rocks, with Pd/Pt

  8. Para-Functionalized NCN-Pincer Palladium and Platinum Complexes as Building Blocks in Organometallic Chemistry

    NARCIS (Netherlands)

    Slagt, Martijn Quico

    2002-01-01

    A rapidly evolving field in chemistry is the application of organometallic and coordination complexes as building blocks or active components for the construction of new materials exhibiting specific catalytic, redox, optical or sensor activities. A central theme in the construction of these inorgan

  9. Ab-initio study of several static and dynamic properties of liquid palladium and platinum

    Directory of Open Access Journals (Sweden)

    González L. E.

    2017-01-01

    Full Text Available We report a study on several static and dynamic properties of liquid Pd and Pt metals at thermodynamic conditions near their respective triple points. The calculations have been carried out by an ab initio molecular dynamics simulation technique. Results are reported for several static structural magnitudes which are compared with the available X-ray diffraction. As for the dynamic properties, results have been obtained for both single and collective dynamical magnitudes as well as for some transport coeffcients which are compared with the corresponding experimental data.

  10. Para-Functionalized NCN-Pincer Palladium and Platinum Complexes as Building Blocks in Organometallic Chemistry

    NARCIS (Netherlands)

    Slagt, Martijn Quico

    2002-01-01

    A rapidly evolving field in chemistry is the application of organometallic and coordination complexes as building blocks or active components for the construction of new materials exhibiting specific catalytic, redox, optical or sensor activities. A central theme in the construction of these inorgan

  11. Comparison of soybean and cottonseed oils upon hydrogenation with nickel, palladium and platinum catalysts

    Science.gov (United States)

    There is current interest in reducing the trans fatty acids (TFA) in hydrogenated vegetable oils because consumption of foods high in TFA has been linked to increased serum cholesterol content. In this work, hydrogenation was carried out on soybean oil and cottonseed oil at two pressures (2 and 5 b...

  12. Active biomonitoring of palladium, platinum, and rhodium emissions from road traffic using transplanted moss.

    Science.gov (United States)

    Suoranta, Terhi; Niemelä, Matti; Poikolainen, Jarmo; Piispanen, Juha; Bokhari, Syed Nadeem Hussain; Meisel, Thomas; Perämäki, Paavo

    2016-08-01

    The use of transplanted moss (Pleurozium schreberi) in active biomonitoring of traffic-related emissions of Pd, Pt, and Rh was studied. Moss mats were transplanted to three locations along highway E75 (in Oulu, Finland) at three different distances from the highway. Five samples were collected from a background site after the same exposure period. Mass fractions of Pd, Pt, and Rh as well as mass fractions of 18 other elements were determined in these samples. The results indicated that P. schreberi is well suited for active biomonitoring of Pd, Pt, and Rh. Mass fractions above the background values were observed in the samples exposed to traffic-related emissions. When the results were compared with those of the other elements, high correlations of Pd, Pt, and Rh with commonly traffic-related elements (e.g., Cu, Ni, Sb, Zn, etc.) were found. It was also found that the amounts of Pd, Pt, and Rh in moss samples decreased when the distance to the highway increased. This trend gives evidence for the suitability of P. schreberi for active biomonitoring of Pd, Pt, and Rh. Furthermore, it can be concluded that the mass fractions determined in this study provide valuable evidence about the current state of Pd, Pt, and Rh emissions in Oulu, Finland.

  13. New palladium, platinum and nickel complexes based on rigid phosphorus and nitrogen containing ligands

    NARCIS (Netherlands)

    vandenBeuken, EK; Meetsma, A; Kooijman, H; Spek, AL; Feringa, BL

    1997-01-01

    Three new polydentate phosphorus nitrogen ligands, 1,3-bis[N,N'-(2-diphenylphosphino)phenylformimidoyl]benzene (3), bis[N,N'-(2-diphenylphosphino)phenyl]-1,3-benzenedicarboxamide (6) and bis [N,N'-(2-diphenylphosphino)phenyl]-2,6-pyridinedicarboxamide (7) with rigid bridging groups have been synthes

  14. Surface characterization of platinum electrodes.

    Science.gov (United States)

    Solla-Gullón, José; Rodríguez, Paramaconi; Herrero, Enrique; Aldaz, Antonio; Feliu, Juan M

    2008-03-14

    The quantitative analysis of the different surface sites on platinum samples is attempted from pure voltammetric data. This analysis requires independent knowledge of the fraction of two-dimensional (111) and (100) domains. Specific site-probe reactions are employed to achieve this goal. Irreversibly-adsorbed bismuth and tellurium have been revealed to be sensitive to the presence of (111) terrace domains of different width whereas almost all sites involved in (100) ordered domains have been characterized through germanium adatoms. The experimental protocol follows that used with well-defined single-crystal electrodes and, therefore, requires careful control of the surface cleanliness. Platinum basal planes and their vicinal stepped surfaces have been employed to obtain calibration plots between the charge density measured under the adatom redox peak, specific for the type of surface site, and the corresponding terrace size. The evaluation of the (100) bidimensional domains can also be achieved using the voltammetric profiles, once the fraction of (111) ordered domains present in the polyoriented platinum has been determined and their featureless contribution has been subtracted from the whole voltammetric response. Using that curve, it is possible to perform a deconvolution of the adsorption states of the polycrystalline sample different from those related to (111) domains. The fraction of (100)-related states in the deconvoluted voltammogram can then be compared to that expected from the independent estimation coming from the charge involved in the redox process undergone by the irreversibly-adsorbed germanium and thus check the result of the deconvolution. The information about the surface-site distribution can also be applied to analyze the voltammetric profile of nanocrystalline platinum electrodes.

  15. Request for Correction 11001 Toxicological Review of Halogenated Platinum Salts and Platinum Compounds

    Science.gov (United States)

    Request for Correction by the International Platinum Group Metals Association seeking the correction of information disseminated in the draft EPA document Toxicological Review of Halogenated Platinum Salts and Platinum Compounds: In Support of Summary Information on the Integrated Risk Information System (IRIS).

  16. Phosphoric acid fuel cell platinum use study

    Science.gov (United States)

    Lundblad, H. L.

    1983-01-01

    The U.S. Department of Energy is promoting the private development of phosphoric acid fuel cell (PAFC) power plants for terrestrial applications. Current PAFC technology utilizes platinum as catalysts in the power electrodes. The possible repercussions that the platinum demand of PAFC power plant commercialization will have on the worldwide supply and price of platinum from the outset of commercialization to the year 2000 are investigated. The platinum demand of PAFC commercialization is estimated by developing forecasts of platinum use per unit of generating capacity and penetration of PAFC power plants into the electric generation market. The ability of the platinum supply market to meet future demands is gauged by assessing the size of platinum reserves and the capability of platinum producers to extract, refine and market sufficient quantities of these reserves. The size and timing of platinum price shifts induced by the added demand of PAFC commercialization are investigated by several analytical methods. Estimates of these price shifts are then used to calculate the subsequent effects on PAFC power plant capital costs.

  17. Leaves of Phragmites australis as potential atmospheric biomonitors of Platinum Group Elements.

    Science.gov (United States)

    Bonanno, Giuseppe; Pavone, Pietro

    2015-04-01

    The increasing emissions of Platinum Group Elements (PGEs), namely Pt, Pd and Rh, may pose a significant risk to ecosystem processes and human health. A periodic assessment of PGEs distribution in the environment is thus of the utmost importance for the implementation of timely measures of mitigation. Although several studies have quantified PGEs in different life forms such as mammals, birds, fish, crustaceans, algae, mosses and even human beings, data about vascular plants need further surveys. This study aimed to test the suitability of the grass Phragmites australis (common reed) as a biomonitor of PGEs atmospheric pollution. The results showed that Pd and Pt concentrations in leaves are significantly higher in urban areas. In particular, Pd showed the highest range of values in line with current studies that consider palladium as the main element of traffic-related pollution. Overall, the leaves of Phragmites australis reflected the different gradient of PGEs emissions, and may thus be considered as potential biomonitors of atmospheric pollution.

  18. Palladium-based Membrane Applications for Hydrogen Purification

    Institute of Scientific and Technical Information of China (English)

    LI Yin'e; MA Guang; JIA Zhihua; JIANG Ting

    2012-01-01

    It describes the purification of hydrogen isotopes,separation with the preparation of palladium-based membrane's technology,types,application,advantages and disadvantages of palladium in this article.Due to excellent comprehensive properties palladium composite membrane will become the future direction of development.At the same time it will develop preparation methods of the membrane support body with high mechanical strength and heat resistance and low-cost and palladium-based membrane.Also it will explore high service life and high transmittance of novel composite membrane.

  19. Functionalized Palladium Nanoparticles for Hydrogen Peroxide Biosensor

    Directory of Open Access Journals (Sweden)

    H. Baccar

    2011-01-01

    Full Text Available We present a comparison between two biosensors for hydrogen peroxide (H2O2 detection. The first biosensor was developed by the immobilization of Horseradish Peroxidase (HRP enzyme on thiol-modified gold electrode. The second biosensor was developed by the immobilization of cysteamine functionalizing palladium nanoparticles on modified gold surface. The amino groups can be activated with glutaraldehyde for horseradish peroxidase immobilization. The detection of hydrogen peroxide was successfully observed in PBS for both biosensors using the cyclic voltammetry and the chronoamperometry techniques. The results show that the limit detection depends on the large surface-to-volume ratio attained with palladium nanoparticles. The second biosensor presents a better detection limit of 7.5 μM in comparison with the first one which is equal to 75 μM.

  20. Effect of alloying with palladium on the electrical and mechanical properties of copper

    Science.gov (United States)

    Volkov, A. Yu.; Novikova, O. S.; Kostina, A. E.; Antonov, B. D.

    2016-09-01

    Structure and physicomechanical properties of Cu-Pd alloys that contain 0.5-5.9 at % Pd have been studied. It has been shown that, in all alloys, a solid solution is formed; the lattice parameter of the fcc lattice and the electrical resistivity of the alloys grow linearly with an increase in the content of palladium. It has also been revealed that the introduction of palladium leads to an increase in the recrystallization temperature and to an increase in the strength properties. The assumption on the formation of an atomic short-range order in the quenched Cu-4.6 at %Pd and Cu-5.9 at %Pd alloys has been made.

  1. Hydrogen in magnesium palladium thin layer structures

    OpenAIRE

    Kruijtzer, G. L.

    2008-01-01

    In this thesis, the study of hydrogen storage, absorption and desorption in magnesium layers is described. The magnesium layers have a thickness of 50-500 nm and are covered by a palladium layer which acts as a hydrogen dissociation/association catalyst. The study was preformed under ultra high vacuum conditions to avoid oxygen contamination. The main analysis techniques were RBS, ERD and TDS.

  2. Sample Characterization of Palladium Supported on Tetraphenylborate

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, M.J.

    2001-04-04

    The primary objective of this research was to use XAFS spectroscopic techniques such as SANES and EXAFS to obtain information on Pd and Hg in samples that were potentially supported on KTPB and had been reacted with dissolved TPB and TPB decomposition products. This work was performed in support of the Small Tank Tetraphenylborate Salt Disposition Alternative program seeking to better understand the mechanism of palladium catalyzed tetraphenylborate decomposition.

  3. Palladium-Catalyzed, Enantioselective Heine Reaction.

    Science.gov (United States)

    Punk, Molly; Merkley, Charlotte; Kennedy, Katlyn; Morgan, Jeremy B

    2016-07-01

    Aziridines are important synthetic intermediates for the generation of nitrogen-containing molecules. N-Acylaziridines undergo rearrangement by ring expansion to produce oxazolines, a process known as the Heine reaction. The first catalytic, enantioselective Heine reaction is reported for meso-N-acylaziridines where a palladium(II)-diphosphine complex is employed. The highly enantioenriched oxazoline products are valuable organic synthons and potential ligands for transition-metal catalysis.

  4. Palladium-catalysed ortho arylation of acetanilides

    Indian Academy of Sciences (India)

    Guo-zhen zhang; Cheng-Qun Chen; Xin-Hua Feng; Guo-Sheng Huang

    2010-03-01

    The palladium-catalysed direct arylation of acetanilides by using C-H activation methodology has been demonstrated. Several acetanilides were coupled with aryl iodides in the presence of 10 mol% of Pd(OAc)2, 1.0 equiv of Cu(OTf)2, and 0.6 equiv of Ag2O to afford the corresponding products in moderate to excellent yields. The results showed that the amount of Ag2O was important for this protocol.

  5. Extracellular Palladium Nanoparticle Production using Geobacter sulfurreducens

    KAUST Repository

    Yates, Matthew D.

    2013-09-03

    Sustainable methods are needed to recycle precious metals and synthesize catalytic nanoparticles. Palladium nanoparticles can be produced via microbial reduction of soluble Pd(II) to Pd(0), but in previous tests using dissimilatory metal reducing bacteria (DMRB), the nanoparticles were closely associated with the cells, occupying potential reductive sites and eliminating the potential for cell reuse. The DMRB Geobacter sulfurreducens was shown here to reduce soluble Pd(II) to Pd(0) nanoparticles primarily outside the cell, reducing the toxicity of metal ions, and allowing nanoparticle recovery without cell destruction that has previously been observed using other microorganisms. Cultures reduced 50 ± 3 mg/L Pd(II) with 1% hydrogen gas (v/v headspace) in 6 h incubation tests [100 mg/L Pd(II) initially], compared to 8 ± 3 mg/L (10 mM acetate) without H2. Acetate was ineffective as an electron donor for palladium removal in the presence or absence of fumarate as an electron acceptor. TEM imaging verified that Pd(0) nanoparticles were predominantly in the EPS surrounding cells in H2-fed cultures, with only a small number of particles visible inside the cell. Separation of the cells and EPS by centrifugation allowed reuse of the cell suspensions and effective nanoparticle recovery. These results demonstrate effective palladium recovery and nanoparticle production using G. sulfurreducens cell suspensions and renewable substrates such as H2 gas. © 2013 American Chemical Society.

  6. Exposure-response analyses for soluble platinum-salt exposed workers and sensitisation: a retrospective cohort study among newly exposed workers using routinely collected surveillance data

    NARCIS (Netherlands)

    Heederik, Dick; Jacobs, Jose; Samadi, Sadegh; Portengen, Lutzen; van Rooy, Frits; Houba, Remko

    OBJECTIVES: Soluble platinum salts are well known respiratory sensitising agents leading to work related sensitisation in the work environment. No quantitative exposure response relation has been described for soluble platinum salts. The objective of this study was to explore exposure response

  7. Effect of Palladium Form on Tetraphenylborate Decomposition Rate

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.D. [Westinghouse Savannah River Company, AIKEN, SC (United States)

    1998-04-28

    Palladium catalyzes the decomposition of tetraphenylborate in alkaline solutions. Researchers postulate several decomposition mechanisms that differ in the form of the palladium catalyst. Potential forms include solid and soluble, different soluble species (such as aqueous or organic soluble), and different oxidation states (i.e., 0, II, and IV). Initial tests measured the reactivity and distribution of four Pd forms in tetraphenylborate slurries.

  8. First determination of the levels of platinum group metals in Manta birostris (manta ray) caught along the Ghanaian coastline.

    Science.gov (United States)

    Essumang, D K

    2010-06-01

    Tissues from Manta birostris caught by fishermen from Dixcove in the western part of Ghana were analyzed for their Platinum, palladium and rhodium concentrations (PGM). The use of chondrichthyan fish has permitted the study of trace levels of Platinum group metals (PGMs) which have travelled very far into the sea. The analysis showed that Ghana's coastline is fairly polluted with these platinum group metals (PGMs). PGM concentration in manta ray recorded a range of (0.15-0.85) microg/g for Pt, (0.033-0.67) microg/g for Pd and (0.007-0.145) microg/g for Rh. Comparing these values to the UK dietary intake of 0.2 microg/day for Pt and Rh and 1.0 microg/day for Pd, its indicates that the values obtained from the analysis for Pt was above the required level. This is the first study to show the accumulation of PGM in chondrichthyan fish, although the sources of this pollution are not clear as manta birostris is migratory and therefore need to be investigated further. The presence of the PGM is very significant, since manta ray meat is consumed in Ghana. This may presents a health risk, due to a possible accumulation of PGMs in humans.

  9. Platinum-induced structural collapse in layered oxide polycrystalline films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianlin; Liu, Changhui [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Huang, Haoliang [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Fu, Zhengping; Peng, Ranran, E-mail: pengrr@ustc.edu.cn, E-mail: yllu@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Zhai, Xiaofang [Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Lu, Yalin, E-mail: pengrr@ustc.edu.cn, E-mail: yllu@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Laser and Optics Research Center, Department of Physics, United States Air Force Academy, Colorado 80840 (United States)

    2015-03-30

    Effect of a platinum bottom electrode on the SrBi{sub 5}Fe{sub 1−x}Co{sub x}Ti{sub 4}O{sub 18} layered oxide polycrystalline films was systematically studied. The doped cobalt ions react with the platinum to form a secondary phase of PtCoO{sub 2}, which has a typical Delafossite structure with a weak antiferromagnetism and an exceptionally high in-plane electrical conductivity. Formation of PtCoO{sub 2} at the interface partially consumes the cobalt dopant and leads to the structural collapsing from 5 to 4 layers, which was confirmed by X-ray diffraction and high resolution transmission electron microscopy measurements. Considering the weak magnetic contribution from PtCoO{sub 2}, the observed ferromagnetism should be intrinsic of the Aurivillius compounds. Ferroelectric properties were also indicated by the piezoresponse force microscopy. In this work, the platinum induced secondary phase at the interface was observed, which has a strong impact on Aurivillius structural configuration and thus the ferromagnetic and ferroelectric properties.

  10. Novel platinum–palladium bimetallic nanoparticles synthesized by Dioscorea bulbifera: anticancer and antioxidant activities

    Science.gov (United States)

    Ghosh, Sougata; Nitnavare, Rahul; Dewle, Ankush; Tomar, Geetanjali B; Chippalkatti, Rohan; More, Piyush; Kitture, Rohini; Kale, Sangeeta; Bellare, Jayesh; Chopade, Balu A

    2015-01-01

    Medicinal plants serve as rich sources of diverse bioactive phytochemicals that might even take part in bioreduction and stabilization of phytogenic nanoparticles with immense therapeutic properties. Herein, we report for the first time the rapid efficient synthesis of novel platinum–palladium bimetallic nanoparticles (Pt–PdNPs) along with individual platinum (PtNPs) and palladium (PdNPs) nanoparticles using a medicinal plant, Dioscorea bulbifera tuber extract (DBTE). High-resolution transmission electron microscopy revealed monodispersed PtNPs of size 2–5 nm, while PdNPs and Pt–PdNPs between 10 and 25 nm. Energy dispersive spectroscopy analysis confirmed 30.88%±1.73% elemental Pt and 68.96%±1.48% elemental Pd in the bimetallic nanoparticles. Fourier transform infrared spectra indicated strong peaks at 3,373 cm−1, attributed to hydroxyl group of polyphenolic compounds in DBTE that might play a key role in bioreduction in addition to the sharp peaks at 2,937, 1,647, 1,518, and 1,024 cm−1, associated with C–H stretching, N–H bending in primary amines, N–O stretching in nitro group, and C–C stretch, respectively. Anticancer activity against HeLa cells showed that Pt–PdNPs exhibited more pronounced cell death of 74.25% compared to individual PtNPs (12.6%) or PdNPs (33.15%). Further, Pt–PdNPs showed an enhanced scavenging activity against 2,2-diphenyl-1-picrylhydrazyl, superoxide, nitric oxide, and hydroxyl radicals. PMID:26719690

  11. Palladium-based dental alloys are associated with oral disease and palladium-induced immune responses

    NARCIS (Netherlands)

    Muris, J.; Scheper, R.J.; Kleverlaan, C.J.; Rustemeyer, T.; van Hoogstraten, I.M.W.; von Blomberg, M.E.; Feilzer, A.J.

    2014-01-01

    Background Palladium (Pd) and gold (Au) based dental alloys have been associated with oral disease. Objectives This study was designed to explore possible associations between the presence of Au-based and Pd-based dental alloys, and oral lesions, systemic complaints, and specific in vivo and in vitr

  12. Modification of platinum surfaces by spontaneous deposition: Methanol oxidation electrocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, J.P.; Gualtieri, B.; Runga, N.; Teliz, E.; Zinola, C.F. [Fundamental Electrochemistry Laboratory, School of Sciences, Universidad de la Republica, Igua Street No. 4225, CP 11400, Montevideo (Uruguay)

    2008-12-15

    The presence of a second metal on platinum surfaces affects the performance of methanol oxidation. However, most of the electrocatalytic reactions are studied by using electrochemically deposited platinum alloys, but in the case of spontaneous deposition the situation is not so clear since the surface distribution, stability and morphology are usually not well documented. The formation of surface decorated samples on mono- and poly-crystalline platinum is followed by electrochemical and spectroscopic techniques and analysis of their performance towards methanol adsorption and oxidation compared with that on pure platinum. Pt/Sn and Pt/Ru are of special interest because of their well-known performance in methanol fuel cells. Methanol oxidation on Pt(111)/Ru, Pt(111)/Sn and Pt(111) shows that ruthenium is the only one able to promote the reaction since the simultaneous dissolution of tin occurs and competes with the process of interest. The in situ infrared spectroscopy is used to compare methanol oxidation on Pt(111)/Ru and Pt(111) in acid media using p-polarized light. The formation of bridge bound carbon monoxide is inhibited in the presence of ruthenium ad-species, whereas on Pt(111) the three adsorption configurations are observed. Linear sweep polarization curves and Tafel slopes (calculated from steady state potentiostatic plots) for methanol oxidation are compared on polycrystalline surfaces modified by tin or ruthenium at different coverages. There is almost no change in the Tafel slopes due to the presence of the foreign metal except for Pt/Ru, where a 0.09 V decade{sup -1} slope was calculated below 0.55 V due to hydroxyl adsorbates on ruthenium islands. The anodic stripping of methanol residues on the three surfaces indicates a lower amount of carbon monoxide-type adsorbates on Pt/Ru, and the simultaneous tin dissolution process leading to residues oxidation on Pt/Sn electrodes. (author)

  13. Characterization of electrochemically modified polycrystalline platinum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, L.C.; Ishida, Takanobu.

    1991-12-01

    The characterization of electrochemically modified polycrystalline platinum surfaces has been accomplished through the use of four major electrochemical techniques. These were chronoamperometry, chronopotentiommetry, cyclic voltammetry, and linear sweep voltammetry. A systematic study on the under-potential deposition of several transition metals has been performed. The most interesting of these were: Ag, Cu, Cd, and Pb. It was determined, by subjecting the platinum electrode surface to a single potential scan between {minus}0.24 and +1.25 V{sub SCE} while stirring the solution, that the electrocatalytic activity would be regenerated. As a consequence of this study, a much simpler method for producing ultra high purity water from acidic permanganate has been developed. This method results in water that surpasses the water produced by pyrocatalytic distillation. It has also been seen that the wettability of polycrystalline platinum surfaces is greatly dependent on the quantity of oxide present. Oxide-free platinum is hydrophobic and gives a contact angle in the range of 55 to 62 degrees. We have also modified polycrystalline platinum surface with the electrically conducting polymer poly-{rho}-phenylene. This polymer is very stable in dilute sulfuric acid solutions, even under applied oxidative potentials. It is also highly resistant to electrochemical hydrogenation. The wettability of the polymer modified platinum surface is severely dependent on the choice of supporting electrolyte chosen for the electrochemical polymerization. Tetraethylammonium tetrafluoroborate produces a film that is as hydrophobic as Teflon, whereas tetraethylammonium perchlorate produces a film that is more hydrophilic than oxide-free platinum.

  14. Hydrodechlorination of Tetrachloromethane over Palladium Catalysts Supported on Mixed MgF₂-MgO Carriers.

    Science.gov (United States)

    Bonarowska, Magdalena; Wojciechowska, Maria; Zieliński, Maciej; Kiderys, Angelika; Zieliński, Michał; Winiarek, Piotr; Karpiński, Zbigniew

    2016-11-25

    Pd/MgO, Pd/MgF₂ and Pd/MgO-MgF₂ catalysts were investigated in the reaction of CCl₄ hydrodechlorination. All the catalysts deactivated in time on stream, but the degree of deactivation varied from catalyst to catalyst. The MgF₂-supported palladium with relatively large metal particles appeared the best catalyst, characterized by good activity and selectivity to C₂-C₅ hydrocarbons. Investigation of post-reaction catalyst samples allowed to find several details associated with the working state of hydrodechlorination catalysts. The role of support acidity was quite complex. On the one hand, a definite, although not very high Lewis acidity of MgF₂ is beneficial for shaping high activity of palladium catalysts. The MgO-MgF₂ support characterized by stronger Lewis acidity than MgF₂ contributes to very good catalytic activity for a relatively long reaction period (~5 h) but subsequent neutralization of stronger acid centers (by coking) eliminates them from the catalyst. On the other hand, the role of acidity evolution, which takes place when basic supports (like MgO) are chlorided during HdCl reactions, is difficult to assess because different events associated with distribution of chlorided support species, leading to partial or even full blocking of the surface of palladium, which plays the role of active component in HdCl reactions.

  15. Evaluating the cytotoxicity of palladium/magnetite nano-catalysts intended for wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrand, Heike, E-mail: heike.hildebrand@ufz.d [Department of Environmental Engineering, UFZ - Helmholtz-Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Kuehnel, Dana [Department of Bioanalytical Ecotoxicology, UFZ - Helmholtz-Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Potthoff, Annegret [Fraunhofer IKTS, Winterbergstr. 28, 01277 Dresden (Germany); Mackenzie, Katrin [Department of Environmental Engineering, UFZ - Helmholtz-Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Springer, Armin [Technical University of Dresden, Institute of Materials Science, Max Bergmann Center of Biomaterials, Budapester Strasse 27, 01069 Dresden (Germany); Schirmer, Kristin [Eawag Swiss Federal Institute of Aquatic Science and Technology, Uberlandstr. 133, 8600 Duebendorf (Switzerland); ETH Zuerich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zuerich (Switzerland)

    2010-01-15

    Palladium/magnetite nanoparticulate catalysts were developed for efficient elimination of halogenated organic pollutants from contaminated wastewater. Particle recovery from treated water can be ensured via magnetic separation. However, in worst-case scenarios, this catalyst removal step might fail, leading to particle release into the environment. Therefore, a toxicological study was conducted to investigate the impact of both pure magnetite and palladium/magnetite nanoparticle exposure upon human skin (HaCaT) and human colon (CaCo-2) cell lines and a cell line from rainbow trout gills (RTgill-W1). To quantify cell viability after particle exposure, three endpoints were examined for all tested cell lines. Additionally, the formation of reactive oxygen species was studied for the human cells. The results showed only minor effects of the particles on the tested cell systems and support the assumption that palladium/magnetite nano-catalysts can be implemented for a new wastewater treatment technology in which advantageous catalyst properties outweigh the risks. - Impact of nano-Pd/magnetite on cell viability was studied and appears to be low.

  16. Electroless plating of ultrathin palladium films: self-initiated deposition and application in microreactor fabrication

    Science.gov (United States)

    Muench, Falk; Oezaslan, Mehtap; Svoboda, Ingrid; Ensinger, Wolfgang

    2015-10-01

    We present new electroless palladium plating reactions, which can be applied to complex-shaped substrates and lead to homogeneous, dense and conformal palladium films consisting of small nanoparticles. Notably, autocatalytic and surface-selective metal deposition could be achieved on a wide range of materials without sensitization and activation pretreatments. This provides a facile and competitive route to directly deposit well-defined palladium nanofilms on e.g. carbon, paper, polymers or glass substrates. The reactions proceed at mild conditions and are based on easily accessible chemicals (reducing agent: hydrazine; metal source: PdCl2; ligands: ethylenediaminetetraacetic acid (EDTA), acetylacetone). Additionally, the water-soluble capping agent 4-dimethylaminopyridine (DMAP) is employed to increase the bath stability, to ensure the formation of small particles and to improve the film conformity. The great potential of the outlined reactions for micro- and nanofabrication is demonstrated by coating an ion-track etched polycarbonate membrane with a uniform Pd film of approximately 20 nm thickness. The as-prepared membrane is then employed as a highly miniaturized flow reactor, using the reduction of 4-nitrophenol with NaBH4 as a model reaction.

  17. Evaluating the cytotoxicity of palladium/magnetite nano-catalysts intended for wastewater treatment.

    Science.gov (United States)

    Hildebrand, Heike; Kühnel, Dana; Potthoff, Annegret; Mackenzie, Katrin; Springer, Armin; Schirmer, Kristin

    2010-01-01

    Palladium/magnetite nanoparticulate catalysts were developed for efficient elimination of halogenated organic pollutants from contaminated wastewater. Particle recovery from treated water can be ensured via magnetic separation. However, in worst-case scenarios, this catalyst removal step might fail, leading to particle release into the environment. Therefore, a toxicological study was conducted to investigate the impact of both pure magnetite and palladium/magnetite nanoparticle exposure upon human skin (HaCaT) and human colon (CaCo-2) cell lines and a cell line from rainbow trout gills (RTgill-W1). To quantify cell viability after particle exposure, three endpoints were examined for all tested cell lines. Additionally, the formation of reactive oxygen species was studied for the human cells. The results showed only minor effects of the particles on the tested cell systems and support the assumption that palladium/magnetite nano-catalysts can be implemented for a new wastewater treatment technology in which advantageous catalyst properties outweigh the risks.

  18. Leading the next boom? competitive Eastern limb platinum supply

    CSIR Research Space (South Africa)

    McGill, JE

    2010-07-01

    Full Text Available and haulage. As such, this often makes it difficult to accurately assess and categorize the degree of mechani- zation of any given mine. Economic aspects The global economic environment exhibits significant variability. Commodity price trends... and delay capital projects. A weaker USD- ZAR exchange rate therefore requires higher commodity prices to offset exchange losses. Undue volatility in the exchange-rate relationship makes long-term planning and forecasting uncertain. The ZAR significantly...

  19. Room temperature synthesis of colloidal platinum nanoparticles

    Indian Academy of Sciences (India)

    G Sarala Devi; V J Rao

    2000-12-01

    Efficient preparation of stable dispersions of platinum nanoparticles from platinous chloride (K2PtCl4) was achieved by simultaneous addition of capping polymer material. The size of platinum nanoparticles was controlled by changing the ratio of concentration of capping polymer material to the concentration of platinum cation used. The morphology of colloidal particles were studied by means of UV-visible spectrophotometry and transmission electron microscopy (TEM). Particle size increased with low reagent concentration. The change in absorption spectra with the particle size was observed, i.e. blue shift attributed to decrease in particle size.

  20. Stabilizing platinum in phosphoric acid fuel cells

    Science.gov (United States)

    Remick, R. J.

    1981-10-01

    A carbon substrate for use in fabricating phosphoric acid fuel cell cathodes was modified by catalytic oxidation to stabilize the platinum catalyst by retarding the sintering of small platinum crystallites. Results of 100-hour operational tests confirmed that the rate of platinum surface area loss observed on catalytically oxidized supports was less than that observed with unmodified supports of the same starting material. Fuel cell electrodes fabricated from Vulcan XC-72R, which was modified by catalytic in a nitric oxide atmosphere, produced low platium sintering rates and high activity for the reduction of oxygen in the phosphoric acid environment.

  1. Antitumor effect of arabinogalactan and platinum complex.

    Science.gov (United States)

    Starkov, A K; Zamay, T N; Savchenko, A A; Ingevatkin, E V; Titova, N M; Kolovskaya, O S; Luzan, N A; Silkin, P P; Kuznetsova, S A

    2016-03-01

    The article presents the results of investigation of antitumor properties of platinum-arabinogalactan complex. We showed the ability of the complex to inhibit the growth of Ehrlich ascites tumor cells. It is found that the distribution of the platinum-arabinogalactan complex is not specific only for tumor cells in mice. The complex was found in all tissues and organs examined (ascites cells, embryonic cells, kidney, and liver). The mechanism of action of the arabinogalactan-platinum complex may be similar to cisplatin as the complex is able to accumulate in tumor cells.

  2. Characterisation of interfaces in nanocrystalline palladium

    Indian Academy of Sciences (India)

    R Divakar; V S Raghunathan

    2003-02-01

    Structures of grain boundaries and triple line junctions in nanocrystalline materials are of interest owing to large fractions of atoms in nanocrystalline materials being at these interfacial positions. Grain boundary and triple line junction structures in nanocrystalline palladium have been studied using high-resolution transmission electron microscopy (HRTEM). The main microstructural features observed include the varying atomic structures of grain boundaries and the presence of disordered regions at triple line junctions. Also, there is variation in lattice parameters in different nanocrystalline grains. Geometric phase analysis is used to quantify atomic displacements within nanocrystalline grains. Displacement fields thus detected indicate links to the interface structures.

  3. Palladium-catalyzed asymmetric quaternary stereocenter formation.

    Science.gov (United States)

    Gottumukkala, Aditya L; Matcha, Kiran; Lutz, Martin; de Vries, Johannes G; Minnaard, Adriaan J

    2012-05-29

    An efficient palladium catalyst is presented for the formation of benzylic quaternary stereocenters by conjugate addition of arylboronic acids to a variety of β,β-disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl(2), PhBOX, and AgSbF(6), and provides products in up to 99% enantiomeric excess, with good yields. Based on this strategy, (-)-α-cuparenone has been prepared in only two steps. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Platinum-Resistor Differential Temperature Sensor

    Science.gov (United States)

    Kolbly, R. B.; Britcliffe, M. J.

    1985-01-01

    Platinum resistance elements used in bridge circuit for measuring temperature difference between two flowing liquids. Temperature errors with circuit are less than 0.01 degrees C over range of 100 degrees C.

  5. VB Platinum Tile & Carpet, Inc. Information Sheet

    Science.gov (United States)

    VB Platinum Tile & Carpet, Inc. (the Company) is located in Bristow, Virginia. The settlement involves renovation activities conducted at a property constructed prior to 1978, located in Washington, DC.

  6. Investigation into the causes of accidents on scraper systems in the gold and platinum mining sectors

    CSIR Research Space (South Africa)

    Moseme, R

    2003-11-01

    Full Text Available and cleaning operations of the scraper winch systems that require identification. This research report identifies the risk and hazards associated with scraper winch systems that may lead to potential accidents in the gold and platinum sector. The research also...

  7. Density functional study on the mechanism for the highly active palladium monolayer supported on titanium carbide for the oxygen reduction reaction

    Science.gov (United States)

    Mao, Jianjun; Li, Shasha; Zhang, Yanxing; Chu, Xingli; Yang, Zongxian

    2016-05-01

    The adsorption, diffusion, and dissociation of O2 on the palladium monolayer supported on TiC(001) surface, MLPd/TiC(001), are investigated using ab initio density functional theory calculations. Strong adhesion of palladium monolayer to the TiC(001) support, accompanied by a modification of electronic structure of the supported palladium, is evidenced. Compared with Pt(111) surface, the MLPd/TiC(001) can enhance the adsorption of O2, leading to comparable dissociation barrier and a smaller diffusion barrier of O2. Whilst the adsorption strength of atomic O (the dissociation product of O2) on MLPd/TiC(001) is similar to that on the Pt(111) surface, possessing high mobility, our theoretical results indicate that MLPd/TiC(001) may serve as a good catalyst for the oxygen reduction reaction.

  8. 萃取色谱法分离实际样品及伴生元素中的铂(Ⅳ)元素%Extraction chromatographic separation of platinum(Ⅳ) from real samples and associated elements

    Institute of Scientific and Technical Information of China (English)

    KOKATE Sudarshan Jagdish; KUCHEKAR Shashikant Raghunath

    2009-01-01

    The extraction behavior of platinum(Ⅳ) was studied with N-n-octylaniline as a function of different parameters,such as pH,concentrations of weak acids,mineral acids,reagents and elution time. A selective method was developed for the extraction chromatographic studies of platinum(Ⅳ) and its separation from several metal ions with N-n-octylaniline (liquid anion exchanger) as a stationary phase on silica gel. The quantitative extraction of platinum(Ⅳ) was observed with 0.067 mol/L N-n-octylaniline and 0.015 mol/L ascorbic acid at pH 1.0. Metal ion was stripped from the column with water and determined spectrophotometrically with stannous chloride method. The proposed method is free from the interference of a large number of cations and anions. Platinum(Ⅳ) was separated from pharmaceutical preparations,alloys and synthetic mixtures. Mutual separation scheme was developed for platinum(Ⅳ),palladium(Ⅱ) and gold(Ⅲ). The log-log plot of N-n-octylaniline concentration versus the distribution ratio indicates that the probable extracted species is [RR~′NH~+_2 ] · Pt(C_6H_7O_6)~-_3.

  9. Design, Synthesis of Novel Platinum(II) Glycoconjugates, and Evaluation of Their Antitumor Effects.

    Science.gov (United States)

    Han, Jianbin; Gao, Xiangqian; Liu, Ran; Yang, Jinna; Zhang, Menghua; Mi, Yi; Shi, Ying; Gao, Qingzhi

    2016-06-01

    A new series of sugar-conjugated (trans-R, R-cyclohexane-1, 2-diamine)-2-halo-malonato-platinum(II) complexes were designed and synthesized to target tumor-specific glucose transporters (GLUTs). The water solubility of the sugar-conjugated platinum (II) complexes was greatly improved by average of 570-fold, 33-fold, and 94-fold, respectively, compared to cisplatin (1.0 mg/mL), carboplatin (17.1 mg/mL), and the newest generation of clinical drug oxaliplatin (6.0 mg/mL). Despite the high water solubility, the platinum(II) glycoconjugates exhibited a notable increase in cytotoxicity by a margin of 1.5- to 6.0-fold in six different human cancer cell lines with respect to oxaliplatin. The potential GLUT1 transportability of the complexes was investigated through a molecular docking study and was confirmed with GLUT1 inhibitor-mediated cytotoxicity dependency evaluation. The results showed that the sugar-conjugated platinum(II) complexes can be recognized by the glucose recognition binding site of GLUT1 and their cell killing effect depends highly on the GLUT1 inhibitor, quercetin. The research presenting a prospective concept for targeted therapy anticancer drug design, and with the analysis of the synthesis, water solubility, antitumor activity, and the transportability of the platinum(II) glycoconjugates, this study provides fundamental data supporting the inherent potential of these designed conjugates as lead compounds for GLUT-mediated tumor targeting.

  10. Reactivity of monofunctional cis-platinum adducts as a function of DNA sequence.

    Science.gov (United States)

    Malinge, J M; Leng, M

    1988-08-11

    The purpose of this work was to study the chemical reactivity of monofunctional cis-platinum-nucleic acid adducts as a function of nucleic acid sequence. The first part of the paper deals with the formation of these adducts. It is shown that the ternary nucleic acid-cis-platinum-ethidium bromide complexes in which ethidium bromide and nucleotide residues are cross-linked by cis-platinum, are relatively unstable at 37 degrees C. In the presence of acridine, ethidium bromide (but not cis-platinum) is slowly released which leads to the formation of monofunctional cis-platinum-nucleic acid adducts. After removal of acridine, the monofunctional adducts react further to become bifunctional. The second part of the paper deals with the kinetics of disappearance of the monofunctional adducts in several polynucleotides but not in poly(dG).poly(dC). When the adducts possess a chloride ligand, the limiting step in the cross-linking is the rate of aquation reaction of the chloride ligand. The rate constants are an order of magnitude larger when the monofunctional adducts do not possess a chloride ligand. In both the cases, the rate constants are apparently independent of the nucleic acid sequence.

  11. Thermally stable single-atom platinum-on-ceria catalysts via atom trapping

    Energy Technology Data Exchange (ETDEWEB)

    Jones, John; Xiong, Haifeng; DelaRiva, Andrew; Peterson, Eric J.; Pham, Hien; Challa, Sivakumar R.; Qi, Gongshin; Oh, Se H.; Wiebenga, Michelle H.; Pereira Hernandez, Xavier I.; Wang, Yong; Datye, Abhaya K.

    2016-07-08

    Catalysts based on single atoms of scarce precious metals can lead to more efficient use through enhanced reactivity and selectivity. However, single atoms on catalyst supports can be mobile and aggregate into nanoparticles when heated at elevated temperatures. High temperatures are detrimental to catalyst performance unless these mobile atoms can be trapped. We used ceria powders having similar surface areas but different exposed surface facets. When mixed with a platinum/ aluminum oxide catalyst and aged in air at 800°C, the platinum transferred to the ceria and was trapped. Polyhedral ceria and nanorods were more effective than ceria cubes at anchoring the platinum. Performing synthesis at high temperatures ensures that only the most stable binding sites are occupied, yielding a sinter-resistant, atomically dispersed catalyst.

  12. Hydrogen Adsorption onto Magnesium Palladium and Magnesium Palladium Niobium Multilayer Thin Films

    Science.gov (United States)

    Steinmetz, Christian; Hettinger, Jeffrey; Dobbins, Tabbetha

    2013-03-01

    We report on the synthesis and characterization of magnesium palladium and magnesium niobium multilayer thin films as a possible reversible hydrogen storage material. The multilayer thin films are characterized by x-ray diffraction (XRD) and x-ray reflectivity (XRR) before and after hydrogen uptake. This study examines the optimal thickness of the magnesium film which would allow the diffusion of hydrogen to form magnesium hydride (MgH2). Thin barriers of palladium and niobium permit hydrogen to permeate while acting as a diffusion barrier to oxygen. Multilayer thin films are grown with various magnesium thicknesses via magnetron sputtering on a sapphire substrate. Thicknesses of Mg, MgH2, Pd, and Nb are reported. Likewise, interfacial roughness attributable to hydrogenation and dehydrogenation cycling measured using XRR are reported.

  13. Effect of palladium on sulfide tarnishing of noble metal alloys.

    Science.gov (United States)

    Suoninen, E; Herø, H; Minni, E

    1985-10-01

    Electron spectroscopic studies of Au-Ag-Cu alloys of the type used for dental castings show that small additions (less than or equal to 3 wt%) of palladium reduce essentially the thickness of the sulfide layer formed on surfaces of samples treated in aqueous Na2S solutions. Relative to silver, palladium does not enrich in the sulfide, but statistically significant enrichment is found immediately below the sulfide layer. This enrichment probably takes place during the exposure of the substrate surface to atmosphere before the sulfiding treatment. The mechanism of the impeding effect of palladium on sulfiding is assumed to be a decrease in diffusion from the bulk alloy to the surface due to the enriched layer. The effect cannot be explained by changes in the electronic structure of the alloy due to palladium alloying.

  14. solid phase extraction of trace amounts of palladium ions using ...

    African Journals Online (AJOL)

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    hydroxybenzylidene)- ... applied to the determination of palladium ion in environmental samples. KEY WORDS: ... preparation tool and provides a method that is simple and safe to use. .... and recovery of ions was investigated under optimum conditions.

  15. A New Palladium-Catalyzed Phenyl-Alkene Bond Formation

    Directory of Open Access Journals (Sweden)

    René Roy

    2002-05-01

    Full Text Available A new method of palladium-catalyzed phenyl-alkene bond formation is reported. This reaction involves transfer of all three phenyl groups from triphenylantimony onto alkenes containing allylic protons.

  16. Highly efficient palladium-catalyzed hydrostannation of ethyl ethynyl ether.

    Science.gov (United States)

    Andrews, Ian P; Kwon, Ohyun

    2008-12-08

    The palladium-catalyzed hydrostannation of acetylenes is widely exploited in organic synthesis as a means of forming vinyl stannanes for use in palladium-catalyzed cross-coupling reactions. Application of this methodology to ethyl ethynyl ether results in an enol ether that is challenging to isolate from the crude reaction mixture because of incompatibility with typical silica gel chromatography. Reported here is a highly efficient procedure for the palladium-catalyzed hydrostannation of ethyl ethynyl ether using 0.1% palladium(0) catalyst and 1.0 equiv of tributyltin hydride. The product obtained is a mixture of regioisomers that can be carried forward with exclusive reaction of the beta-isomer. This method is highly reproducible; relative to previously reported procedures, it is more economical and involves a more facile purification procedure.

  17. Rational Design of Porous Conjugated Polymers and Roles of Residual Palladium for Photocatalytic Hydrogen Production.

    Science.gov (United States)

    Li, Lianwei; Cai, Zhengxu; Wu, Qinghe; Lo, Wai-Yip; Zhang, Na; Chen, Lin X; Yu, Luping

    2016-06-22

    Developing highly efficient photocatalyts for water splitting is one of the grand challenges in solar energy conversion. Here, we report the rational design and synthesis of porous conjugated polymer (PCP) that photocatalytically generates hydrogen from water splitting. The design mimics natural photosynthetics systems with conjugated polymer component to harvest photons and the transition metal part to facilitate catalytic activities. A series of PCPs have been synthesized with different light harvesting chromophores and transition metal binding bipyridyl (bpy) sites. The photocatalytic activity of these bpy-containing PCPs can be greatly enhanced due to the improved light absorption, better wettability, local ordering structure, and the improved charge separation process. The PCP made of strong and fully conjugated donor chromophore DBD (M4) shows the highest hydrogen production rate at ∼33 μmol/h. The results indicate that copolymerization between a strong electron donor and weak electron acceptor into the same polymer chain is a useful strategy for developing efficient photocatalysts. This study also reveals that the residual palladium in the PCP networks plays a key role for the catalytic performance. The hydrogen generation activity of PCP photocatalyst can be further enhanced to 164 μmol/h with an apparent quantum yield of 1.8% at 350 nm by loading 2 wt % of extra platinum cocatalyst.

  18. Study on Systemic Separation of Palladium, Silver, Cadmium and Tin

    Institute of Scientific and Technical Information of China (English)

    YU; Zhen-hua; HUANG; Kun

    2013-01-01

    To accurately measure the yields of palladium,silver,cadmium and tin that generated from the fission of plutonium,radiochemical method is needed because there is much interference in using directγ-spectroscopy measurements.Usually,we want to get as much as possible the experiment data from one target,so it is required systemic separation of palladium,silver,cadmium and tin.Considering the

  19. Platinum-group elements and minerals in the lower and middle group chromitites of the western Bushveld Complex, South Africa

    Science.gov (United States)

    Junge, Malte; Oberthür, Thomas; Osbahr, Inga; Gutter, Paul

    2016-10-01

    The chromitites of the Bushveld Complex in South Africa contain vast resources of platinum-group elements (PGE). However, knowledge of the distribution and the mineralogical siting of the PGE in the lower group (LG) and middle group (MG) chromitite seams of the Bushveld Complex is limited. We studied concentrates from the LG-6 and MG-2 chromitites of the western Bushveld Complex by a variety of microanalytical techniques. The dominant PGM are sulfides, namely laurite, cooperite-braggite, and malanite-cuprorhodsite, followed by PGE-sulfarsenides, sperrylite, and Pt-Fe alloys. Laurite is the most abundant PGM (vol%). The matching sets of PGM present in the LG and MG chromitites of both the western and the eastern Bushveld Complex, and in the UG-2 chromitite, show strong similarities which support the assumption of a characteristic and general chromitite-related PGM assemblage. Palladium and Rh contents in pentlandite are low and erratic although maximum contents of 7730 ppm Pd and 6020 ppm Rh were detected. Rare thiospinels of the polydymite-linnaeite-greigite series have PGE contents of 1430 ppm Pt, 5370 ppm Rh, and 1460 ppm Pd. The various PGE occur in different deportment: Platinum is generally present in the form of discrete PGM (sulfides, arsenides, alloys). Palladium is present as a large variety of discrete PGM and also incorporated in pentlandite. Rhodium forms discrete PGM and is occasionally present in pentlandite. The IPGE (Os, Ir, and Ru) are dominantly incorporated in laurite (often as inclusions in chromite) and also occur as sulfarsenides.

  20. High Hydrogen Loading of Thin Palladium Wires Through

    CERN Document Server

    Celani, F; Marini, P; Di Stefano, V; Nakamura, M; Pace, S; Vecchione, A; Mancini, A; Tripodi, P; Di Gioacchino, D

    2000-01-01

    A new protocol for the electrolytic loading of hydrogen (H) in thin palladium (Pd) wires has been developed. In order to increase the cathodic overvoltage, which is known to be the main parameter capable to enhance the electrolytic $9 H loading of Pd, the catalytic action of the Pd surface versus H-H recombination has been strongly reduced by precipitation of a thin layer of alkaline-earth carbonates on the cathode. A set of electrolytes has been employed, $9 containing small amounts of hydrochloric or sulphuric acid and strontium or calcium ions. The H loading has been continuously evaluated through ac measurements of the Pd wire resistance. Uncommonly low resistivity values, leading to $9 an estimate of exceptionally high H loading, have been observed. Evidence of the existence of a new phase in the very high H content region of the Pd-H system has been inferred on the basis of the determination of the temperature $9 coefficient of the electrical resistivity. For this purpose a thin layer of Hg was galvanic...

  1. Palladium Catalyzed Allylic C-H Alkylation: A Mechanistic Perspective

    Directory of Open Access Journals (Sweden)

    Casper Junker Engelin

    2011-01-01

    Full Text Available The atom-efficiency of one of the most widely used catalytic reactions for forging C-C bonds, the Tsuji-Trost reaction, is limited by the need of preoxidized reagents. This limitation can be overcome by utilization of the recently discovered palladium-catalyzed C-H activation, the allylic C-H alkylation reaction which is the topic of the current review. Particular emphasis is put on current mechanistic proposals for the three reaction types comprising the overall transformation: C-H activation, nucleophillic addition, and re-oxidation of the active catalyst. Recent advances in C-H bond activation are highlighted with emphasis on those leading to C-C bond formation, but where it was deemed necessary for the general understanding of the process closely related C-H oxidations and aminations are also included. It is found that C-H cleavage is most likely achieved by ligand participation which could involve an acetate ion coordinated to Pd. Several of the reported systems rely on benzoquinone for re-oxidation of the active catalyst. The scope for nucleophilic addition in allylic C-H alkylation is currently limited, due to demands on pKa of the nucleophile. This limitation could be due to the pH dependence of the benzoquinone/hydroquinone redox couple. Alternative methods for re-oxidation that does not rely on benzoquinone could be able to alleviate this limitation.

  2. computer modeling ter modeling ter modeling of platinum reforming ...

    African Journals Online (AJOL)

    eobe

    naphtha to complex chemical reactions, at h temperature and ... at is leaving any stage of the platinum reforming reactors in terms of ... In this study, only platinum reforming .... IV. Hydrocracking of paraffinic hydrocarbons: +. →. ( +. +. +. +. ) (18).

  3. Novel platinum black electroplating technique improving mechanical stability.

    Science.gov (United States)

    Kim, Raeyoung; Nam, Yoonkey

    2013-01-01

    Platinum black microelectrodes are widely used as an effective neural signal recording sensor. The simple fabrication process, high quality signal recording and proper biocompatibility are the main advantages of platinum black microelectrodes. When microelectrodes are exposed to actual biological system, various physical stimuli are applied. However, the porous structure of platinum black is vulnerable to external stimuli and destroyed easily. The impedance level of the microelectrode increases when the microelectrodes are damaged resulting in decreased recording performance. In this study, we developed mechanically stable platinum black microelectrodes by adding polydopamine. The polydopamine layer was added between the platinum black structures by electrodeposition method. The initial impedance level of platinum black only microelectrodes and polydopamine added microelectrodes were similar but after applying ultrasonication the impedance value dramatically increased for platinum black only microelectrodes, whereas polydopamine added microelectrodes showed little increase which were nearly retained initial values. Polydopamine added platinum black microelectrodes are expected to extend the availability as neural sensors.

  4. Platinum uptake from chloride solutions using biosorbents

    Directory of Open Access Journals (Sweden)

    Mehmet Hakan Morcali

    2013-04-01

    Full Text Available Present work investigates platinum uptake from synthetically prepared, dilute platinum-bearing solutions using biomass residues, i.e. pistachio nut shell and rice husk, which are abundant in Turkey, and provides a comparison between these two biosorbents. Effects of the different uptake parameters, sorbent dosage, contact time, temperature and pH of solution on platinum uptake (% were studied in detail on a batch sorption. Before the pistachio nut shell was activated, platinum uptake (% was poor compared to the rice husk. However, after the pistachio nut shell was activated at 1000 °C under an argon atmosphere, the platinum uptake (% increased two-fold. The pistachio nut shell (original and activated and rice husk were shown to be better than commercially available activated carbon in terms of adsorption capacity. These two sorbents have also been characterized by FTIR and SEM. Adsorption equilibrium data best complied with the Langmuir isotherm model. Maximum adsorption capacities, Qmax, at 25 °C were found to be 38.31 and 42.02 mg.g- 1for the activated pistachio nut shell and rice husk, respectively. Thermodynamic calculations using the measured ∆H°, ∆S° and ∆G° values indicate that the uptake process was spontaneous and endothermic. The experimental data were shown to be fit the pseudo-second-order kinetic model.

  5. Effect of palladium on the reducibility of Mn based materials: correlation with methane oxidation activity.

    Science.gov (United States)

    Baylet, A; Royer, S; Labrugère, C; Valencia, H; Marécot, P; Tatibouët, J M; Duprez, D

    2008-10-21

    Mn-based oxide supports were synthesized using different procedures: (i) carbonate co-precipitation method, leading to the formation of a hexaaluminate crystallized solid (La(0.2)Sr(0.3)Ba(0.5)MnAl(11)O(19)) and (ii) solid-solid diffusion method, leading to the formation of a doped theta-Al(2)O(3) crystallized solid (nominal composition: 60 wt% La(0.2)Sr(0.3)Ba(0.5)MnAl(11)O(19) + 40 wt% Al(2)O(3)). Impregnation of 1.0 wt%Pd was carried out on both oxides. The solids were tested for the catalytic methane combustion up to 700 degrees C. It was observed that adding palladium resulted in an important increase in the catalytic activity. The combined use of H(2)-TPR and XPS techniques reveals that only Mn(3+)/Mn(2+) redox "couple" is present in the solids, whatever the synthesis procedure used. The fraction Mn(3+)/Mn is proportional to the total Mn content in the solid support, whatever the sample structure (hexaaluminate or doped theta-Al(2)O(3)) and its morphology (large crystals or aggregates of small particles, respectively). Pd impregnation and further calcination at 650 degrees C has no significant effect on the Mn(3+)/Mn fraction. However, some changes in Mn(3+) reduction profile are observed, depending on the solid structure. Indeed, palladium addition strongly affects the manganese reducibility with an important shift of the reduction process to lower temperatures (approximately 100 degrees C). On the basis of redox properties observed for the different catalysts, a Mars-van-Krevelen redox mechanism, with oxygen transfer from support oxides to palladium particles, is proposed to explain the difference in terms of catalytic conversion and stability with respect to a 1.0 wt%Pd/Al(2)O(3) reference sample.

  6. Electrochemical Fabrication and Electrocatalytic Properties of Nanostructured Mesoporous Platinum Microelectrodes

    Institute of Scientific and Technical Information of China (English)

    Mengyan NIE; Joanne M. Elliott

    2005-01-01

    Electrodeposition from a lyotropic liquid crystal template medium was used to produce nanostructured platinum microelectrodes with high specific surface area and high mass transport efficiency. Compared to polished and conventional platinized microelectrodes, well-ordered nanostructured platinum microelectrodes exhibited enhanced electrocatalytic properties for oxygen and ascorbic acid, whilst well-ordered nanostructured platinum microelectrodes offered improved electrocatalytic properties for oxygen reduction compared to disordered nanostructured platinum microelectrodes.

  7. Scientific Opinion on the safety assessment of the active substances, palladium metal and hydrogen gas, for use in active food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2014-02-01

    Full Text Available This scientific opinion of EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety assessment of the active substances palladium metal (CAS No 7440-05-3, FCM No 993 and hydrogen gas (CAS No 1333-74-0, FCM No 1038, which are intended to be used as an oxygen scavenger in packages of foods and beverages at room temperature or below. The active article is designed as a gas permeable but liquid impermeable laminated pad, which is placed within a cap or closure or as an adhesive label on tray lids. The palladium metal is not in direct contact with the food being separated from it by different layers of passive materials. The specific migration of palladium metal into conventional food simulants was not detected at the limit of quantification of 0.6 µg/kg. Palladium was considered to be non genotoxic and of no toxicological concern under a low exposure level resulting from a concentration up to 50 µg/kg food in a previous evaluation (EFSA CEF Panel, 2012. Based on these previously drawn conclusions and given the intended conditions of use leading to non-detectable migration, the CEF Panel concluded that the active substances palladium and hydrogen do not raise a safety concern for the consumer when used as an oxygen scavenger in packages for foods and beverages at room temperatures or below. Palladium should not be in direct contact with food and should be incorporated in a passive structure impermeable to liquids which prevents the migration at detectable levels.

  8. Extensions of Callendar's equations for platinum resistance thermometry

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1969-01-01

    measurements where the platinum thermometer and the measurement means may be less than ideal. To this end. Callendar's definition of platinum temperature is generalized to mean the temperature found by linear interpolation with a platinum thermometer between given fixed points and using a given measurement...

  9. Platinum Publications as of April 30, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  10. Platinum Publications, September 30–October 27, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  11. Platinum Publications as of June 25, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  12. Platinum Publications, July 1–July 28, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  13. Platinum Publications as of March 6, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  14. Platinum Publications, October 1–29, 2015 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  15. Platinum Publications, December 1–December 29, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  16. Platinum Publications as of May 29, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  17. Platinum Publications as of September 25, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  18. Platinum Publications, January 26–February 28, 2017 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  19. Platinum Publications as of December 3, 2013 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  20. Deposition of the platinum crystals on the carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new technique and the affecting factors for depositing platinum on the carbon nanotubes were investigated. The results show that the deposited platinum crystals in the atmosphere of hydrogen or nitrogen have a small size and a homogeneous distribution on the surface of the carbon nanotubes. The pretreatment would decrease the platinum particles on the carbon nanotubes significantly.

  1. 76 FR 8627 - Revision of Class E Airspace; Platinum, AK

    Science.gov (United States)

    2011-02-15

    ... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Platinum, AK AGENCY: Federal... Platinum, AK, to accommodate the addition of a Standard Instrument Approach Procedure (SIAP), at the Platinum Airport. The FAA is taking this action to enhance safety and management of Instrument Flight...

  2. Annexin A3 Is a Potential Predictor of Platinum Resistance in Epithelial Ovarian Cancer Patients in a Prospective Cohort.

    Science.gov (United States)

    Jin, Ying; Feng, Li-Ping; Jiang, Xiang; Wang, Yong-Xue; Yin, Jie; Yang, Zi-Ping; Li, Yan; Pan, Ling-Ya

    2015-01-01

    Epithelial ovarian cancer (EOC) is the leading cause of death among gynecological malignancies and is rarely cured in the recurrent setting, mainly because of progressive chemoresistance, especially platinum resistance. In our previous studies, the platinum-resistance-related protein, annexin A3, was selected by comparative proteomics. In this study, we detected serum annexin A3 levels using a self-developed chemiluminescence immunoassay kit in a prospective EOC patient cohort. We also evaluated the capacity of serum annexin A3 levels to predict platinum resistance. Serum annexin A3 levels in healthy women exhibited a similar normal distribution (Z=0.723, P=0.673), allowing determination of a normal cutoff level of 0.11-1.45 ng/mL. Of the 89 EOC patients, 21 were platinum resistant and 68 were platinum sensitive. Residual disease after primary surgery (p=0.004) and serum annexin A3 levels (p=0.036) were both independent factors associated with platinum resistance. The AUC was 0.733 (95% confidence interval (CI), 0.627-0.823). The optimal cutoff value for serum annexin A3 levels was 2.05 ng/mL. Multivariate logistic analysis showed that expression of annexin A3 as assessed by immunohistochemistry (P=0.005) and residual tumor size (P=0.000) had a significant influence on platinum resistance. The AUC of ROC curve of annexin A3 expression by immunohistochemistry was 0.664 (95% CI, 0.554-0.763) and the cut off value was ">=moderate scores". In conclusion, we demonstrate that annexin A3 is a secreted protein that may be measured in the peripheral blood using a self-developed, chemiluminescence immunoassay kit. Serum annexin A3 levels may be a potential predictor of platinum resistance in epithelial ovarian cancer patients.

  3. Surface decorated platinum carbonyl clusters

    Science.gov (United States)

    Ciabatti, Iacopo; Femoni, Cristina; Iapalucci, Maria Carmela; Longoni, Giuliano; Zacchini, Stefano; Zarra, Salvatore

    2012-06-01

    Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters.Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters. CCDC 867747 and 867748. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30400g

  4. Autonomous movement of platinum-loaded stomatocytes.

    Science.gov (United States)

    Wilson, Daniela A; Nolte, Roeland J M; van Hest, Jan C M

    2012-02-26

    Polymer stomatocytes are bowl-shaped structures of nanosize dimensions formed by the controlled deformation of polymer vesicles. The stable nanocavity and strict control of the opening are ideal for the physical entrapment of nanoparticles which, when catalytically active, can turn the stomatocyte morphology into a nanoreactor. Herein we report an approach to generate autonomous movement of the polymer stomatocytes by selectively entrapping catalytically active platinum nanoparticles within their nanocavities and subsequently using catalysis as a driving force for movement. Hydrogen peroxide is free to access the inner stomatocyte cavity, where it is decomposed by the active catalyst (the entrapped platinum nanoparticles) into oxygen and water. This generates a rapid discharge, which induces thrust and directional movement. The design of the platinum-loaded stomatocytes resembles a miniature monopropellant rocket engine, in which the controlled opening of the stomatocytes directs the expulsion of the decomposition products away from the reaction chamber (inner stomatocyte cavity).

  5. ORR viability of alumina-supported platinum nanocluster: exploring oxidation behaviour by DFT.

    Science.gov (United States)

    Nigam, Sandeep; Majumder, Chiranjib

    2017-07-26

    While alumina-supported platinum particles are versatile for several oxidation reactions, their viability as ORR catalysts has not been explored to date. Therefore, to assess the prospects of alumina-supported platinum nanoclusters in ORRs, a systematic DFT study has been carried out to explore the oxidation behavior of a Ptn@Al2O3 (n = 1-7, 10) cluster. The results are compared with the oxidation behavior of the corresponding gas phase platinum cluster and that of an extended Pt(111) slab. Both supported and unsupported clusters activate adsorbed oxygen molecules and energetically favor dissociative chemisorption of oxygen, leading to stable oxide formation with Pt-O-Pt linkages. However, the influence of the alumina substrate downshifts the d-band centre of the platinum cluster, which not only reduces the reaction enthalpy of oxidation by 8-10%, but also elongates the Pt-O bond of the oxide product by 3-8%. These observations indicate that removal of oxide will be relatively easier for supported clusters than for unsupported clusters. Cluster binding is found to sustain during oxidation, as oxidation of the platinum host cluster results in reduction of the distance between the cluster and support surface. While the gas phase Pt10 cluster does not show any similarity to the oxidation behavior shown by THE Pt(111) slab, the Pt10@Al2O3 cluster reveals close resemblance. Both the Pt(111) slab and Pt10@Al2O3 cluster form similar oxide products, having tri-coordinated oxygen with comparable Pt-O bond distances. The observed resemblance has been attributed to the similarity in the electronic structure and d-band centre position of the platinum surface and alumina-supported Pt10 cluster. Whilst this similar oxidation behaviour of the Pt10@Al2O3 cluster endorses its viability as an ORR catalyst, further modulation of this catalyst is desirable to improve its potential.

  6. Comparison of different sample preparation methods for platinum determination in cultured cells by graphite furnace atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Man Xiao

    2017-01-01

    Full Text Available Background Platinum-based agents are widely used in chemotherapy against solid tumors and insufficient intracellular drug accumulation is one of the leading causes of platinum resistance which is associated with poor survival of tumor patients. Thus, the detection of intracellular platinum is pivotal for studies aiming to overcome platinum resistance. In the present study, we aimed to establish a reliable graphite furnace atomic absorption spectrometry (GFAAS-based assay to quantify the intracellular platinum content for cultured cells. Methods Several most commonly applied cell preparation methods, including 0.2% HNO3, 0.2% Triton X-100, concentrated nitric acid, RIPA combined with concentrated nitric acid and hydroxide, followed by GFAAS for platinum detection were compared in ovarian, cervical and liver cancer cell lines to obtain the optimal one, and parameters regarding linearity, accuracy, precision and sensitivity were evaluated. Influence of other metals on platinum detection and the storage conditions of samples were also determined. Results The treatment of cells with 0.2% HNO3 was superior to other approaches with fewer platinum loss and better repeatability. The recovery rate and precision of this method were 97.3%–103.0% and 1.4%–3.8%, respectively. The average recoveries in the presence of other metals were 95.1%–103.1%. The detection limit was 13.23 ug/L. The recovery rate of platinum remained acceptable even in cell samples stored in −20 °C or −80 °C for two months. Discussion After comparison, we found that 0.2% HNO3 was optimal for intracellular platinum quantification based on GFAAS, which presented values compatible with that of inductively-coupled plasma mass-spectrometry (ICP-MS, and this is partially attributed to the simplicity of this method. Moreover, the assay was proved to be accurate, sensitive, cost-effective and suitable for the research of platinum-based antitumor therapy.

  7. Metal allergen of the 21st century--a review on exposure, epidemiology and clinical manifestations of palladium allergy

    DEFF Research Database (Denmark)

    Faurschou, Annesofie; Menné, Torkil; Johansen, Jeanne D;

    2011-01-01

    Consumers are mainly exposed to palladium from jewellery and dental restorations. Palladium contact allergy is nearly always seen together with nickel allergy, as palladium and nickel tend to cross-react. We aimed to analyse the available palladium patch test data and case reports to determine wh...

  8. Electrochemical Analysis of the Electrodeposition of Platinum Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-Min; Cho, Sung-Woon; Kim, Jun-Hyun; Kim, Chang-Koo [Ajou University, Suwon (Korea, Republic of)

    2015-10-15

    A bath for electrodeposition of platinum nanoparticles on low-cost graphite substrates was developed to attach nanoparticles directly onto a substrate, and electrochemical characteristics of the electrodeposition of platinum nanoparticles were investigated. The reaction mechanism was examined by the analysis of polarization behavior. Cyclic voltammetry measurements revealed that the electrodeposition of platinum nanoparticles was limited by mass transfer. The chronoamperometric study showed an instantaneous nucleation mechanism during the electrodeposition of platinum nanoparticles on graphite. Because graphite is much cheaper than other carbon-based substrates, the electrodeposition of platinum nanoparticles on the graphite is expected to have useful applications.

  9. Outpatient desensitization in selected patients with platinum hypersensitivity reactions.

    Science.gov (United States)

    O'Malley, David M; Vetter, Monica Hagan; Cohn, David E; Khan, Ambar; Hays, John L

    2017-06-01

    Platinum-based chemotherapies are a standard treatment for both initial and recurrent gynecologic cancers. Given this widespread use, it is important to be aware of the features of platinum hypersensitivity reactions and the subsequent treatment of these reactions. There is also increasing interest in the development of desensitization protocols to allow patients with a history of platinum hypersensitivity to receive further platinum based therapy. In this review, we describe the management of platinum hypersensitivity reactions and the desensitization protocols utilized at our institution. We also describe the clinical categorizations utilized to triage patients to appropriate desensitization protocols. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Synthesis and characterization of new platinum(II) and platinum(IV) triphyrin complexes.

    Science.gov (United States)

    Xue, Zhaoli; Kuzuhara, Daiki; Ikeda, Shinya; Okujima, Tetsuo; Mori, Shigeki; Uno, Hidemitsu; Yamada, Hiroko

    2013-02-18

    Metalation of 6,13,20,21-tetrakis(4-methylphenyl)-22H-tribenzo[14]triphyrin(2.1.1) with PtCl(2) gave a platinum(II) complex having a square-planar coordination structure with two pyrrolic nitrogen atoms and two chloride ions, with a saddle-shaped macrocycle. This platinum(II) complex was easily oxidized by air to an octahedral platinum(IV) complex coordinated by three pyrrolic nitrogen atoms as a tridentate monoanionic cyclic ligand and three chloride ions. When platinum(II) triphyrin was crystallized in air, an oxygen atom was incorporated between two α-carbon atoms of the pyrroles as an oxygen bridge to intercept the 14π aromatic system.

  11. Hydrodehalogenation of bromo- and chloropyridines over palladium complex and palladium metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gurovets, A.S.; Sharf, V.Z.; Belen' kii, L.I.

    1986-03-01

    The hydrodehalogenation of 2-chloro-, 2-bromo-, 3-bromo, and 3,5-dibromopyridine has been studied in the presence of a palladium complex catalyst immobilized on silica gel, and a Pd/C catalyst. Cleavage of bromine from bromopyridines over the Pd complex is significantly faster than from the bromo-substituted furanes and thiophenes previously studied. Debromination over Pd/C is faster than over the complex catalyst. Over both catalysts 3-bromopyridine debrominates faster than the 2-isomer. When molecular deuterium is used, the respective deuterated pyridines can be obtained.

  12. Sulfur tolerant zeolite supported platinum catalysts for aromatics hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Bergem, Haakon

    1997-12-31

    The increased demand for transportation fuels at the expence of heavier fuel oil has forced the refinery industry to expand their conversion capacity with hydrotreating as one of the key processes. A shift towards more diesel powered vehicles along with tightening fuel regulations demanding cleaner fuels has lead to increasing interest in catalytic processes for the manufacturing of such environmentally acceptable fuels. This provides the motivation for this thesis. Its main objective was to study possible catalysts active for desulfurization, hydrogenation, and ring-opening of aromatics all in the presence of sulfur. A close examination of the physical properties and kinetical behaviour of the chosen catalysts has been performed. A high pressure reactor setup was designed and built for activity measurements. Zeolite supported platinum catalysts were prepared and both the metal and acid functions were characterized utilizing various experimental techniques. Hydrogenation of toluene was used as a model reaction and the effect of sulfur adsorption on the activity and kinetic behaviour of the catalysts was investigated. The catalyst samples showed hydrogenation activities comparable to a commercial Pt/Al2O3 catalyst. There were no clear differences in the effect of the various sulfur compounds studied. Platinum supported on zeolite Y gave considerably more sulfur tolerant catalysts compared to Al2O3 as support. 155 refs., 58 figs., 36 tabs.

  13. Palladium nanoparticles exposure: Evaluation of permeation through damaged and intact human skin.

    Science.gov (United States)

    Larese Filon, Francesca; Crosera, Matteo; Mauro, Marcella; Baracchini, Elena; Bovenzi, Massimo; Montini, Tiziano; Fornasiero, Paolo; Adami, Gianpiero

    2016-07-01

    The intensified use of palladium nanoparticles (PdNPs) in many chemical reactions, jewellery, electronic devices, in car catalytic converters and in biomedical applications lead to a significant increase in palladium exposure. Pd can cause allergic contact dermatitis when in contact with the skin. However, there is still a lack of toxicological data related to nano-structured palladium and information on human cutaneous absorption. In fact, PdNPs, can be absorbed through the skin in higher amounts than bulk Pd because NPs can release more ions. In our study, we evaluated the absorption of PdNPs, with a size of 10.7 ± 2.8 nm, using intact and damaged human skin in Franz cells. 0.60 mg cm(-2) of PdNPs were applied on skin surface for 24 h. Pd concentrations in the receiving solutions at the end of experiments were 0.098 ± 0.067 μg cm(-2) and 1.06 ± 0.44 μg cm(-2) in intact skin and damaged skin, respectively. Pd flux permeation after 24 h was 0.005 ± 0.003 μg cm(-2) h(-1) and 0.057 ± 0.030 μg cm(-2) h(-1) and lag time 4.8 ± 1.7 and 4.2 ± 3.6 h, for intact and damaged skin respectively. This study indicates that Pd can penetrate human skin.

  14. Analyses of platinum group elements in mosses as indicators of road traffic emissions in Austria

    Science.gov (United States)

    Zechmeister, Harald G.; Hagendorfer, Harald; Hohenwallner, Daniela; Hanus-Illnar, Andrea; Riss, Alarich

    The concentrations of platinum group elements (PGE; platinum, palladium, rhodium) and 17 other elements in mosses growing at 32 sampling sites along 12 roads in Austria were analysed. The study included passive monitoring of naturally growing mosses with an experimental design using mosses samples exposed in a tunnel experiment. PGEs (Pt, Pd, Rh) were analysed by ICP-MS (ELAN DRC II, Perkin Elmer SCIEX) according to EN ISO 17294-2 Tl.29. Mean concentrations of PGEs in five moss species were: Pt 7.07±9.97, Pd 2.8±5.2 und Rh 0.6±0.8 ng g -1 dry weight. This is comparable to data derived from measurements of gasoline autocatalyst emissions or airborne particles (<10 μm). Compared to soils and road dust along highways, concentrations in mosses were lower by a factor of ten, compared to grasses they were comparable or somewhat higher. The ratios between the various PGEs were calculated as follows (mean values): Pt/Pd 7.9±10.2, Pt/Rh 12.6±8.3 and Pd/Rh 3.7±2.2. The number of light duty vehicles (<3.5 t) and the distance from the road were the main influential factors for PGE concentrations. Especially strong correlations could be found between Pt and Sb, Cu, Zn, and Cd (in decreasing order), which are all elements derived mainly from road traffic emissions. Cluster analysis (Partioning Around Medoids Method) separated elements derived mainly from soil dust (Ca, Al). An analysis of spatial deposition patterns of PGEs showed a reciprocal decrease of concentrations with increasing distance from the road, reaching background values at distances between 10 and 200 m, sometimes even more, but outside the spatial range of our investigation.

  15. Extraction of palladium(Ⅱ) with OTMSO from acidic media

    Institute of Scientific and Technical Information of China (English)

    WU Songping; MENG Shuyuan; GU Guobang; ZHUANG Zhiqiang

    2004-01-01

    The extraction of palladium(Ⅱ) from acidic media with cyclic sulfoxide derivative-α-octyl-tetrahydrothiophene-l-oxide (OTMSO) was investigated. The extraction efficiency of palladination number was studied with slope method. The result indicates that coordination number is 2. FT-IR spectra were used to analyze the structure of complex and coordinated atom in complex. Pd is coordinated with both oxygen and sulfur atom in S=O group in OTMSO .The situation and intensity of peaks contributed by complex prepared from various acidity were different. The recovery of palladium(Ⅱ) with OTMSO from scrap containing palladium was discussed. After silver and bismuth were removed, the feed solution was extracted three times by 40% (volume fraction) OTMSO-kerosene. The loaded organic phase was scrubbed three times,and stripped three times by 2 mol@L-1 NH3·H2O solution.The total recovery of palladium was 99.8%,and the purity of palladium was 99.8%.

  16. Atomistic simulation of helium bubble nucleation in palladium

    Energy Technology Data Exchange (ETDEWEB)

    Wang Liang [Department of Applied Physics, Hunan University, Changsha 410082 (China); Hu, Wangyu [Department of Applied Physics, Hunan University, Changsha 410082 (China)], E-mail: wangyuhu2001cn@yahoo.com.cn; Xiao Shifang [Department of Applied Physics, Hunan University, Changsha 410082 (China)], E-mail: sfxiao@yahoo.com.cn; Yang Jianyu [Department of Maths and Physics, Hunan Institute of Engineering, Xiangtan 411104 (China); Deng Huiqiu [Department of Applied Physics, Hunan University, Changsha 410082 (China)

    2009-09-15

    A palladium crystal has been constructed with 11808 atoms. 55 helium atoms occupied the octahedral position of palladium crystal are introduced and retained in a spherical region. Molecular dynamic simulations are performed in a constant temperature and constant volume ensemble (NVT) with temperature controlled by Nose-Hoover thermostat. The interactions between palladium atoms are described with modified analytic embedded atom method (MAEAM), the interactions between palladium atom and helium atom are in the form of Morse potential, and the interactions between helium atoms are in the form of L-J potential function. With the analysis of the radial distribution function (RDF) and microstructure, it reveals that some of helium atoms form a series of clusters with different size, and the nucleation core is random at low temperature, and which is the embryo of helium bubble. Increasing temperature can accelerate the process of bubble nucleation, and the clusters will aggregate and coalesce into a bigger one in which there are no palladium atoms, and it is considered as a helium bubble.

  17. Anticancer platinum (IV) prodrugs with novel modes of activity.

    Science.gov (United States)

    Chin, Chee Fei; Wong, Daniel Yuan Qiang; Jothibasu, Ramasamy; Ang, Wee Han

    2011-01-01

    Over the past four decades, the search for improved platinum drugs based on the classical platinum (II)-diam(m)ine pharmacophore has yielded only a handful of successful candidates. New methodologies centred on platinum (IV) complexes, with better stability and expanded coordination spheres, offer the possibility of overcoming limitations inherent to platinum (II) drugs. In this review, novel strategies of targeting and killing cancer cells using platinum (IV) constructs are discussed. These approaches exploit the unique electrochemical characteristics and structural attributes of platinum (IV) complexes as a means of developing anticancer prodrugs that can target and selectively destroy cancer cells. Anticancer platinum (IV) prodrugs represent promising new strategies as targeted chemotherapeutic agents in the ongoing battle against cancer.

  18. The Dynamics of Platinum Precipitation in an Ion Exchange Membrane

    CERN Document Server

    Burlatsky, S F; Atrazhev, V V; Dmitriev, D V; Kuzminyh, N Y; Erikhman, N S

    2013-01-01

    Microscopy of polymer electrolyte membranes that have undergone operation under fuel cell conditions, have revealed a well defined band of platinum in the membrane. Here, we propose a physics based model that captures the mechanism of platinum precipitation in the polymer electrolyte membrane. While platinum is observed throughout the membrane, the preferential growth of platinum at the band of platinum is dependent on the electrochemical potential distribution in the membrane. In this paper, the location of the platinum band is calculated as a function of the gas concentration at the cathode and anode, gas diffusion coefficients and solubility constants of the gases in the membrane, which are functions of relative humidity. Under H2/N2 conditions the platinum band is located near the cathode-membrane interface, as the oxygen concentration in the cathode gas stream increases and/or the hydrogen concentration in the anode gas stream decreases, the band moves towards the anode. The model developed in this paper...

  19. Platinum compounds with anti-tumour activity

    NARCIS (Netherlands)

    Plooy, A.C.M.; Lohman, P.H.M.

    1980-01-01

    Ten platinum (Pt) coordination complexes with different ligands, comprising both Pt(II) and Pt(IV) complexes of which the cis-compounds all possessed at least some anti-tumour activity and the trans-compounds were inactive, were tested as to their effect on cell survival and the induction and repair

  20. On the enzymatic formation of platinum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Govender, Y.; Riddin, T. L. [Rhodes University, Department of Biochemistry, Microbiology and Biotechnology (South Africa); Gericke, M. [MINTEK (South Africa); Whiteley, C. G., E-mail: C.Whiteley@ru.ac.z [Rhodes University, Department of Biochemistry, Microbiology and Biotechnology (South Africa)

    2010-01-15

    A dimeric hydrogenase enzyme (44.5 and 39.4 kDa sub units) was isolated in a 39.5% yield from the fungus Fusarium oxysporum and purified 4.64-fold by ion exchange chromatography on Sephacryl S-200. Characterisation of the enzyme afforded pH and temperature optima of 7.5 and 38 {sup o}C, respectively, a half-life stability of 36 min and a V{sub max} and K{sub m} of 3.57 nmol min{sup -1} mL{sup -1} and 2.25 mM, respectively. This enzyme was inhibited (non-competitively) by hydrogen hexachloroplatinic acid (H{sub 2}PtCl{sub 6}) at 1 or 2 mM with a K{sub i} value of 118 {mu}M. Incubation of the platinum salt with the pure enzyme under an atmosphere of hydrogen and optimum enzyme conditions (pH 7.5, 38 {sup o}C) afforded <10% bioreduction after 8 h while at conditions suitable for platinum nanoparticle formation (pH 9, 65 {sup o}C) over 90% reduction took place after the same length of time. Cell-free extract from the fungal isolates produced nearly 90% bioreduction of the platinum salt under both pH and temperature conditions. The bioreduction of the platinum salt by a hydrogenase enzyme takes place by a passive process and not an active one as previously understood.

  1. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de

    2000-01-01

    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported.

  2. Skin Sensitizing Potency of Halogenated Platinum Salts.

    Science.gov (United States)

    The relationship between occupational exposure to halogenated platinum (Pt) salts and Pt-specific allergic sensitization is well-established. Although human case reports and clinical studies demonstrate that Pt salts are potent skin sensitizers, no studies have been published tha...

  3. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de

    2000-01-01

    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported. Is

  4. Synthesis and characterization of thermally stable palladium-based composite membranes for high temperature applications

    Science.gov (United States)

    Abu El Hawa, Hani W.

    In this thesis, the inert gas leak evolution problem in electroless-plated palladium-based composite membranes has been revisited. Palladium was doped with a higher melting point element such as ruthenium or platinum and the rate of increase of the nitrogen leak in the temperature range of 500-600 ºC was determined. The results showed that doping Pd with Pt or Ru significantly reduces the leak growth rate compared to a pure Pd membrane by almost one order of magnitude. The addition of Ru to Pd was sufficient to lower the leak growth rate, though the hydrogen permeance stability was not improved. The Pd-Pt alloy membrane, despite having a lower hydrogen permeance, had a stable hydrogen flux at higher temperatures. The influence of high temperature annealing (> 640 ºC) on the thermal stability of pure Pd composite membranes was also investigated in order to correlate between thermal stability and microstructural evolution. Pure Pd composite membranes were subjected to different high temperature annealing processes. It was found that employing such heat treatments improved the thermal stability of the membranes when operated at lower temperatures; evidenced by a suppression of the rate at which hydrogen selectivity towards nitrogen declined over time. SEM images of the microstructural evolution as a function of temperature revealed that porosity, which is typically present in as-deposited electroless plated films, is significantly reduced after heat treatment. Thermal stability was also evaluated in actual steam methane reforming (SMR) environments. Thin film (˜5.0 microm thick) Pd-Ru and Pd-Au composite membranes were fabricated and used to carry out SMR over commercial Ni or Ru based catalysts at temperatures > 480 °C and pressures up to 2.9 MPa. The conversions obtained (≥ 80%) were significantly higher than the thermodynamic equilibrium predicted (process conditions. The long term operation (> 500 hours) revealed the potential suitability of these Pd

  5. Testing of a 7-tube palladium membrane reactor for potential use in TEP

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Bryan J [Los Alamos National Laboratory; Trujillo, Stephen [Los Alamos National Laboratory; Willms, R. Scott [Los Alamos National Laboratory

    2010-01-01

    A Palladium Membrane Reactor (PMR) consists of a palladium/silver membrane permeator filled with catalyst (catalyst may be inside or outside the membrane tubes). The PMR is designed to recover tritium from the methane, water, and other impurities present in fusion reactor effluent. A key feature of a PMR is that the total hydrogen isotope content of a stream is significantly reduced as (1) methane-steam reforming and/or water-gas shift reactions proceed on the catalyst bed and (2) hydrogen isotopes are removed via permeation through the membrane. With a PMR design matched to processing requirements, nearly complete hydrogen isotope removals can be achieved. A 3-tube PMR study was recently completed. From the results presented in this study, it was possible to conclude that a PMR is appropriate for TEP, perforated metal tube protectors function well, platinum on aluminum (PtA) catalyst performs the best, conditioning with air is probably required to properly condition the Pd/Ag tubes, and that CO/CO{sub 2} ratios maybe an indicator of coking. The 3-tube PMR had a permeator membrane area of 0.0247 m{sup 2} and a catalyst volume to membrane area ratio of 4.63 cc/cm{sup 2} (with the catalyst on the outside of the membrane tubes and the catalyst only covering the membrane tube length). A PMR for TEP will require a larger membrane area (perhaps 0.35 m{sup 2}). With this in mind, an intermediate sized PMR was constructed. This PMR has 7 permeator tubes and a total membrane area of 0.0851 m{sup 2}. The catalyst volume to membrane area ratio for the 7-tube PMR was 5.18 cc/cm{sup 2}. The total membrane area of the 7-tube PMR (0.0851 m{sup 2}) is 3.45 times larger than total membrane area of the 3-tube PMR (0.0247 m{sup 2}). The following objectives were identified for the 7-tube PMR tests: (1) Refine test measurements, especially humidity and flow; (2) Refine maintenance procedures for Pd/Ag tube conditioning; (3) Evaluate baseline PMR operating conditions; (4) Determine PMR

  6. Targeted treatment of folate receptor-positive platinum-resistant ovarian cancer and companion diagnostics, with specific focus on vintafolide and etarfolatide

    OpenAIRE

    Serpe L; Gallicchio M; Canaparo R; Dosio F

    2014-01-01

    Loredana Serpe, Margherita Gallicchio, Roberto Canaparo, Franco DosioDepartment of Drug Science and Technology, University of Turin, ItalyAbstract: Among the gynecological malignancies, ovarian cancer is the leading cause of mortality in developed countries. Treatment of ovarian cancer is based on surgery integrated with chemotherapy. Platinum-based drugs (cisplatin and carboplatin) comprise the core of first-line chemotherapy for patients with advanced ovarian cancer. Platinum-resistant ovar...

  7. cis-Diammine[3-(3-chloro-7-methoxy-9,10-dihydroacridin-9-ylideneaminopropan-1-amine-κ2N,N′]platinum(II dinitrate

    Directory of Open Access Journals (Sweden)

    Young Cheun

    2016-04-01

    Full Text Available The title complex salt, [Pt(C16H17N3(NH32](NO32, is of interest with respect to anticancer activity. The secondary amine of 9-aminoacridine coordinates with the platinum(II atom, leading to imine–platinum complex cation formation. The crystal structure displays extensive N—H...O and N—H...N hydrogen bonding and weak C—H...Cl and C—H...O hydrogen bonding.

  8. The mechanism of corrosion of palladium-silver binary alloys in artificial saliva.

    Science.gov (United States)

    Joska, L; Marek, M; Leitner, J

    2005-05-01

    Palladium dental casting alloys are alternatives to gold alloys. The aim of this study was to determine the electrochemical behaviour and the corrosion mechanism of binary silver-palladium alloys. Seven binary silver-palladium alloys and pure palladium and silver were tested in a model saliva solution. Electrochemical tests included corrosion potential, polarization resistance, and potentiodynamic polarization measurements. The corrosion products, which may be theoretically formed, were determined by thermodynamic calculation. The behaviour of silver and silver-rich alloys was dominated by the preferential formation of a thiocyanate surface layer, which controlled the free corrosion potential. Palladium dissolved in the form of a thiocyanate complex, but the surface became passivated by either palladium oxide or solid palladium thiocyanate layer, the thermodynamic calculations indicating preference for the oxide. Palladium-rich alloys showed evidence of silver depletion of the surface, resulting in behaviour similar to palladium. Examination of binary silver-palladium alloys has made possible determination of the role of the components of the alloys and model saliva in the corrosion behaviour. The findings are applicable to the more complex commercial dental alloys containing silver and palladium as major components.

  9. Higher fluorescence in platinum(iv) orthometallated complexes of perylene imine compared with their platinum(ii) or palladium(ii) analogues.

    Science.gov (United States)

    Expósito, J Emilio; Álvarez-Paíno, Marta; Aullón, Gabriel; Miguel, Jesús A; Espinet, Pablo

    2015-09-28

    The reaction of 3-perylenylmethylen-4'-ethylaniline () with [Pt2Me4(μ-SMe2)2] (and subsequent addition of PPh3) or with [Pt2(η(3)-C4H7)2(μ-Cl)2] produced cyclometallated Pt(II) complexes [Pt(C^N)Me(PPh3)] () and, respectively, [Pt2(C^N)2(μ-Cl)2] () (HC^N = 3-C20H11CH[double bond, length as m-dash]NC6H4-p-C2H5), with Pt bound to the ortho site of the perylenyl fragment. From the mononuclear complexes [Pt(C^N)L2] (L2 = acac (); S2COMe (); S2CNEt2 () are easily formed. Oxidative addition of methyl iodide to the square-planar Pt(II) complexes , , and gave the corresponding cyclometallated Pt(IV) compounds [Pt(C^N)L2MeI] , and . The X-ray structures of , , and show that the perylenyl fragment remains essentially flat in and and slightly twisted in . Comparison of the optical properties of these Pt(II) complexes with those reported for similar Pd(II) derivatives reveals that the change of metal exerts a notable influence on the UV-vis spectra. In solution at room temperature, all the Pt complexes exhibit fluorescence associated with the perylene fragment with low emission quantum yields for the Pt(II) complexes (IV) complexes: up to 29%, with emission lifetimes of 1-5 ns. Time-dependent density functional theory (TD-DFT) calculations were performed on the perylene imine and on representative complexes [M(C^N)(acac)] (M = Pd, Pt) and [Pt(C^N)(acac)MeI] to analyse the absorption spectra. These calculations support a perylene-dominated intraligand π-π*emissive state based on the HOMO and LUMO orbitals of the perylene chromophore, and a ligand-to-ligand charge-transfer (more intense for the Pt(II) complex) that explains the observed influence of the metal on the absorption properties.

  10. Local magnetism in palladium bionanomaterials probed by muon spectroscopy.

    Science.gov (United States)

    Creamer, Neil J; Mikheenko, Iryna P; Johnson, Clive; Cottrell, Stephen P; Macaskie, Lynne E

    2011-05-01

    Palladium bionanomaterial was manufactured using the sulfate-reducing bacterium, Desulfovibrio desulfuricansm, to reduce soluble Pd(II) ions to cell-bound Pd(0) in the presence of hydrogen. The biomaterial was examined using a Superconducting Quantum Interference Device (SQUID) to measure bulk magnetisation and by Muon Spin Rotation Spectroscopy (µSR) which is uniquely able to probe the local magnetic environment inside the sample. Results showed behaviour attributable to interaction of muons both with palladium electrons and the nuclei of hydrogen trapped in the particles during manufacture. Electronic magnetism, also suggested by SQUID, is not characteristic of bulk palladium and is consistent with the presence of nanoparticles previously seen in electron micrographs. We show the first use of μSR as a tool to probe the internal magnetic environment of a biologically-derived nanocatalyst material.

  11. Mechanism of extracting palladium(Ⅱ) with cyclic sulfoxide derivatives

    Institute of Scientific and Technical Information of China (English)

    吴松平; 孟淑媛; 古国榜; 庄志强; 刘会冲

    2004-01-01

    The extraction ability of palladium( Ⅱ ) from acidic media with cyclic sulfoxide derivatives-α-Dodecyl-tetrahydrothiophene 1-Oxide (DTMSO), α-octyl-tetrahydrothiophene 1-Oxide (OTMSO) and α-butyl-tetrahydro-thiophene-1-Oxide (BTMSO) was investigated. The extracting efficiency of cyclic sulfoxide derivatives decreased with the increasing of acidity in the lower acidity, and the efficiency became stable with the change of acidity in the higher acidity. The extraction reaction of palladium( Ⅱ )with DTMSO is exothermic, and extraction reaction of pal-ladium( Ⅱ ) is endothermic when OTMSO or BTMSO were used as extracting reagents. The coordination number was studied by slope method. The results indicate that coordination number is 2, and the composition of complex is Pd is coordinated with both oxygen and sulfur atom in S=O group in sulfoxide derivatives.

  12. Palladium-Catalyzed Modification of Unprotected Nucleosides, Nucleotides, and Oligonucleotides

    Directory of Open Access Journals (Sweden)

    Kevin H. Shaughnessy

    2015-05-01

    Full Text Available Synthetic modification of nucleoside structures provides access to molecules of interest as pharmaceuticals, biochemical probes, and models to study diseases. Covalent modification of the purine and pyrimidine bases is an important strategy for the synthesis of these adducts. Palladium-catalyzed cross-coupling is a powerful method to attach groups to the base heterocycles through the formation of new carbon-carbon and carbon-heteroatom bonds. In this review, approaches to palladium-catalyzed modification of unprotected nucleosides, nucleotides, and oligonucleotides are reviewed. Polar reaction media, such as water or polar aprotic solvents, allow reactions to be performed directly on the hydrophilic nucleosides and nucleotides without the need to use protecting groups. Homogeneous aqueous-phase coupling reactions catalyzed by palladium complexes of water-soluble ligands provide a general approach to the synthesis of modified nucleosides, nucleotides, and oligonucleotides.

  13. Selective palladium electrochemical deposition onto AFM-scratched silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Santinacci, L.; Djenizian, T.; Hildebrand, H.; Ecoffey, S.; Mokdad, H.; Campanella, T.; Schmuki, P

    2003-09-30

    The present work investigates the selective electrochemical deposition of palladium nano-structures into scratches produced through thin oxide layers covering p-Si (1 0 0) surfaces. Using an atomic force microscope equipped with a single-crystalline diamond tip scratches in the 100 nm range were produced through a 10 nm thick dry oxide layer. Pd deposition was carried out in PdCl{sub 2} (0.01 g l{sup -1})+HCl (0.1 M) by cathodic potential steps. Investigation of the palladium nucleation and growth processes onto silicon surfaces is presented. Under optimized conditions sub-100 nm palladium structures can be obtained with a very high selectivity.

  14. Hydrodechlorination of Tetrachloromethane over Palladium Catalysts Supported on Mixed MgF2-MgO Carriers

    Directory of Open Access Journals (Sweden)

    Magdalena Bonarowska

    2016-11-01

    Full Text Available Pd/MgO, Pd/MgF2 and Pd/MgO-MgF2 catalysts were investigated in the reaction of CCl4 hydrodechlorination. All the catalysts deactivated in time on stream, but the degree of deactivation varied from catalyst to catalyst. The MgF2-supported palladium with relatively large metal particles appeared the best catalyst, characterized by good activity and selectivity to C2-C5 hydrocarbons. Investigation of post-reaction catalyst samples allowed to find several details associated with the working state of hydrodechlorination catalysts. The role of support acidity was quite complex. On the one hand, a definite, although not very high Lewis acidity of MgF2 is beneficial for shaping high activity of palladium catalysts. The MgO-MgF2 support characterized by stronger Lewis acidity than MgF2 contributes to very good catalytic activity for a relatively long reaction period (~5 h but subsequent neutralization of stronger acid centers (by coking eliminates them from the catalyst. On the other hand, the role of acidity evolution, which takes place when basic supports (like MgO are chlorided during HdCl reactions, is difficult to assess because different events associated with distribution of chlorided support species, leading to partial or even full blocking of the surface of palladium, which plays the role of active component in HdCl reactions.

  15. Fabrication of Nitrogen-Doped Mesoporous-Carbon-Coated Palladium Nanoparticles: An Intriguing Electrocatalyst for Methanol and Formic Acid Oxidation.

    Science.gov (United States)

    Ray, Chaiti; Dutta, Soumen; Sahoo, Ramkrishna; Roy, Anindita; Negishi, Yuichi; Pal, Tarasankar

    2016-05-20

    Inspired by the attractive catalytic properties of palladium and the inert nature of carbon supports in catalysis, a concise and simple methodology for in situ nitrogen-doped mesoporous-carbon-supported palladium nanoparticles (Pd/N-C) has been developed by carbonizing a palladium dimethylglyoximate complex. The as-synthesized Pd/N-C has been exfoliated as a fuel cell catalyst by studying the electro-oxidation of methanol and formic acid. The material synthesized at 400 °C,namely, Pd/N-C-400,exhibitssuperior mass activity and stability among catalysts synthesized under different carbonization temperaturesbetween300 and 500 °C. The unique 1D porous structure in Pd/N-C-400 helps better electron transport at the electrode surface, which eventually leads to about five times better catalytic activity and about two times higher stability than that of commercial Pd/C. Thus, our designed sacrificial metal-organic templatedirected pathway becomes a promising technique for Pd/N-C synthesis with superior catalytic performances. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A sensitivity study of the oxidation of compressed natural gas on platinum

    KAUST Repository

    Badra, Jihad

    2013-11-01

    This paper presents a sensitivity study for the oxidation of methane (CH4) over platinum (Pt). Some dominant reactions in the CH 4-Pt surface chemistry were identified and the rates of these reactions were subsequently modified to enhance the calculations. Initially, a range of CH4-Pt surface mechanisms available in the literature are used, along with the relevant detailed gaseous chemistry to compute the structure of premixed compressed natural gas (CNG)/air flames co-flowing around a flat, vertical, unconfined, rectangular, and platinum plate. Comparison with existing measurements of surface temperature and species concentrations revealed significant discrepancies for all mechanisms. Sensitivity analysis has identified nine key reactions which dominate the heterogeneous chemistry of methane over platinum. The rates of these reactions were modified over a reasonable range and in different combinations leading to an "optimal" mechanism for methane/air surface chemistry on platinum. The new mechanism is then used with the same flow geometry for different cases varying the temperature of the incoming mixture (Tjet), its equivalence ratio (Φ) and the Reynolds number (Re). Results from the modified surface mechanism demonstrate reasonably good agreement with the experimental data for a wide range of operating conditions. © 2013 Elsevier Ltd. All rights reserved.

  17. 2-Deoxyglucose conjugated platinum (II) complexes for targeted therapy: design, synthesis, and antitumor activity.

    Science.gov (United States)

    Mi, Qian; Ma, Yuru; Gao, Xiangqian; Liu, Ran; Liu, Pengxing; Mi, Yi; Fu, Xuegang; Gao, Qingzhi

    2016-11-01

    Malignant neoplasms exhibit an elevated rate of glycolysis over normal cells. To target the Warburg effect, we designed a new series of 2-deoxyglucose (2-DG) conjugated platinum (II) complexes for glucose transporter 1 (GLUT1)-mediated anticancer drug delivery. The potential GLUT1 transportability of the complexes was investigated through a comparative molecular docking analysis utilizing the latest GLUT1 protein crystal structure. The key binding site for 2-DG as GLUT1's substrate was identified with molecular dynamics simulation, and the docking study demonstrated that the 2-DG conjugated platinum (II) complexes can be recognized by the same binding site as potential GLUT1 substrate. The conjugates were synthesized and evaluated for in vitro cytotoxicity study with seven human cancer cell lines. The results of this study revealed that 2-DG conjugated platinum (II) complexes are GLUT1 transportable substrates and exhibit improved cytotoxicities in cancer cell lines that over express GLUT1 when compared to the clinical drug, Oxaliplatin. The correlation between GLUT1 expression and antitumor effects are also confirmed. The study provides fundamental information supporting the potential of the 2-DG conjugated platinum (II) complexes as lead compounds for further pharmaceutical R&D.

  18. Palladium-Catalyzed Arylation of Fluoroalkylamines

    Science.gov (United States)

    Brusoe, Andrew T.; Hartwig, John F.

    2015-01-01

    We report the synthesis of fluorinated anilines by palladium-catalyzed coupling of fluoroalkylamines with aryl bromides and aryl chlorides. The products of these reactions are valuable because anilines typically require the presence of an electron-withdrawing substituent on nitrogen to suppress aerobic or metabolic oxidation, and the fluoroalkyl groups have steric properties and polarity distinct from those of more common electron-withdrawing amide and sulfonamide units. The fluoroalkylaniline products are unstable under typical conditions for C–N coupling reactions (heat and strong base). However, the reactions conducted with the weaker base KOPh, which has rarely been used in cross-coupling to form C–N bonds, occurred in high yield in the presence of a catalyst derived from commercially available AdBippyPhos and [Pd(allyl)Cl]2. Under these conditions, the reactions occur with low catalyst loadings (<0.50 mol % for most substrates) and tolerate the presence of various functional groups that react with the strong bases that are typically used in Pd-catalyzed C–N cross-coupling reactions of aryl halides. The resting state of the catalyst is the phenoxide complex, (BippyPhosPd(Ar)OPh); due to the electron-withdrawing property of the fluoroalkyl substituent, the turnover-limiting step of the reaction is reductive elimination to form the C–N bond. PMID:26065341

  19. On the structure of small palladium particles

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, R.; Avalos-Borja, M.; Schabes-Retchkiman, P.; Romeu, D.; Jose-Yacaman, M. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Fisica); Ponce, F. (Xerox Palo Alto Research Center, CA (USA))

    1989-09-01

    The study of small noble metal particles is becoming increasingly important in many fields in physics (1). The advent of high-resolution electron microscopy (HREM) has allowed a deeper understanding of structural aspects of small particles. This work reports the study of particles of palladium with a diameter less than 3 nm. Specimens were prepared by in-situ deposition of Pd onto thin carbon films under near-UHV conditions in the specimen preparation chamber. Faulted decahedral MTP was grown using a recursive (R) growth model which generates infinite, space-filling structures reproducing the structure of crystals, twinned particles and quasicrystals. R growth consists of the formation of a cluster by iterative addition of points (atoms) from a given star vector. The method presented sheds some light on a point that has been controversial in the past about the nature of MTP's. Some authors have claimed that these structures can be considered as FCC twins with a disclination to close the resulting gap. The fact that they can be obtained quite simply from stable smaller units appears to make the disclination unnecessary.

  20. Role of Palladium in the Redox Electrochemistry of Ferrocene Monocarboxylic Acid Encapsulated Within ORMOSIL Networks

    Directory of Open Access Journals (Sweden)

    B. Upadhyay

    2005-07-01

    Full Text Available We report herein the effect of palladium on the redox electrochemistry of ferrocene monocarboxylic acid encapsulated within an organically modified sol-gel glass network (ORMOSIL. It has been found that amount of palladium and its geometrical distribution significantly alter the redox electrochemistry of FcMCA. The geometrical distribution of palladium has been controlled by two methods: (i palladium is allowed to link within nanostructured network of the ORMOSIL which was subsequently availed from the reactivity of palladium chloride and trimethoxysilane; (ii palladium powder is encapsulated together FcMCA thus allowing the presence of palladium within the nanoporous domain. The content of palladium is varied by controlling the reaction dynamics of palladium chloride and trimethoxysilane interaction. For this we initially allowed to trigger hydrolysis, condensation and poly-condensation of trimethoxysilane and dimethyldiethoxysilane in acidic medium and subsequently partially dried ORMOSIL film was allowed to interact with palladium chloride. Even with partially dried ORMOSIL derived from trimethoxysilane and dimethyldiethoxysilane undergoes rapid interaction with palladium chloride and the transparent color of ORMOSIL changed to a black colour due to the formation of palladium silicon linkage. The palladium-silicon linkage has been identified by NMR, UV-VIS and transmission electron spectroscopy. The electrochemistry of FcMCA encapsulated within such an ORMOSIL matrix has been studied. Excellent redox electrochemistry of ferrocene monocarboxylic acid having peak potential separation tending to 0 for a multilayered electrode was investigated. The palladium content has been found to affect the redox electrochemistry of ferrocene as well as electrocatalytic efficiency of new ORMOSIL material. The electroanalysis of NADH is reported. The modified electrode is very sensitive to NADH with lowest detection limit of < 1 μM.

  1. Morphological Study Of Palladium Thin Films Deposited By Sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Salcedo, K L; Rodriguez, C A [Grupo Plasma Laser y Aplicaciones, Ingenieria Fisica, Universidad Tecnologica de Pereira (Colombia); Perez, F A [WNANO, West Virginia University (United States); Riascos, H [Grupo Plasma Laser y Aplicaciones, Departamento de Fisica, Universidad Tecnologica de Pereira (Colombia)

    2011-01-01

    This paper presents a morphological analysis of thin films of palladium (Pd) deposited on a substrate of sapphire (Al{sub 2}O{sub 3}) at a constant pressure of 3.5 mbar at different substrate temperatures (473 K, 523 K and 573 K). The films were morphologically characterized by means of an Atomic Force Microscopy (AFM); finding a relation between the roughness and the temperature. A morphological analysis of the samples through AFM was carried out and the roughness was measured by simulating the X-ray reflectivity curve using GenX software. A direct relation between the experimental and simulation data of the Palladium thin films was found.

  2. Phase Transitions in Even-Even Palladium Isotopes

    Directory of Open Access Journals (Sweden)

    Diab S. M.

    2009-01-01

    Full Text Available The positive and negative parity states of the even-even palladium isotopes were stud- ied within the frame work of the interacting boson approximation model (IBA-1. The energy spectra, potential energy surfaces, electromagnetic transition probabilities, back bending and staggering effect have been calculated. The potential energy surfaces show smooth transition from vibrational-like to gamma-soft and finally to rotational-like nu- clei. Staggering effectle, has been observed between the positive and negative parity states in palladium isotopes. The agreement between theoretical predictions and exper- imental values are fairly good.

  3. Palladium based nanomaterials for enhanced hydrogen spillover and storage

    Directory of Open Access Journals (Sweden)

    Suresh K. Konda

    2016-03-01

    Full Text Available Hydrogen storage remains one of the most challenging prerequisites to overcome toward the realization of a hydrogen based economy. The use of hydrogen as an energy carrier for fuel cell applications has been limited by the lack of safe and effective hydrogen storage materials. Palladium has high affinity for hydrogen sorption and has been extensively studied, both in the gas phase and under electrochemical conditions. In this review, recent advancements are highlighted and discussed in regard to palladium based nanomaterials for hydrogen storage, as well as the effects of hydrogen spillover on various adsorbents including carbons, metal organic frameworks, covalent organic frameworks, and other nanomaterials.

  4. 一种含钯物料中钯的回收%Recovery of Palladium from a Palladium Material

    Institute of Scientific and Technical Information of China (English)

    徐涛

    2015-01-01

    The traditional method of ammonium chloride recovery of palladium process was improved. By adding oxidant palladium adjusted to Pd(IV) morphology, and speed of adding HCl was slowed down to reduce Pd content in tail solution. The recovery rate palladium reached 98.5%.%对传统的氯化铵法回收钯工艺进行了改进,采用添加氧化剂的方式将钯调整为Pd(Ⅳ)形态,控制加入盐酸的速度,减少钯在尾液中的量,使钯的回收率达到98.5%以上。

  5. Concurrent chemoradiotherapy comparison of taxanes and platinum versus 5-fluorouracil and platinum in nasopharyngeal carcinoma treatment

    Institute of Scientific and Technical Information of China (English)

    Chen Xichuang; Hong Yuan; Feng Jinhua; Ye Jianlin; Zheng Panpan; Guan Xiyin; You Xiaohong

    2014-01-01

    Background Nasopharyngeal carcinoma (NPC) is a squamous-cell carcinoma especially prevailing among the natives of southern China.The regimen of concurrent chemoradiotherapy (CCRT) that include platinum and 5-fluorouracil (5-FU)is considered to be the standard treatment for NPC.However,its clinical use is limited by its toxicity.Our purpose was to evaluate the efficacy and safety of the regimen of CCRT with taxanes and platinum versus the regimen of CCRT with 5-FU and platinum in NPC treatment.Methods Medline,the Cochrane library,and the Chinese medical literature database were searched for eligible studies.Meta-analysis was performed using Review Manager (Version 5.2).Results Six random controlled trials (RCTs) including 514 patients met our criteria.Meta-analysis showed that the regimen of CCRT with taxanes and platinum had an improved significant difference in complete remission (CR) and less incidence rate in adverse reactions such as gastrointestinal impairment grades Ⅲll-Ⅳ,liver and kidney impairment grades Ⅰ-Ⅱ,and radiodermatitis grades Ⅲ-Ⅳ versus the conventional regimen of CCRT with 5-FU and platinum,while the long-term effectiveness rate of overall survival,Iocoregional failure-free survival,or distant metastasis failure-free survival between the two groups was therapeutic equivalence.Conclusions The regimen of CCRT with taxanes and platinum in NPC therapy may be more efficient and safe compared to the conventional modality of 5-FU and platinum in CCRT.However,we need more high-quality studies of multi-center and randomized double-blind clinical trials to further compare,analyze,and confirm the findings.

  6. β-Hydrogen Elimination Reactions of Nickel and Palladium Methoxides Stabilised by PCP Pincer Ligands.

    Science.gov (United States)

    Martínez-Prieto, Luis M; Ávila, Elena; Palma, Pilar; Álvarez, Eleuterio; Cámpora, Juan

    2015-06-26

    Nickel and palladium methoxides [((iPr)PCP)M-OMe], which contain the (iPr)PCP pincer ligand, decompose upon heating to give products of different kinds. The palladium derivative cleanly gives the dimeric Pd(0) complex [Pd(μ-(iPr)PCHP)]2 ((iPr)PCHP = 2,6-bis(diisopropylphosphinomethyl)phenyl) and formaldehyde. In contrast, decomposition of [((iPr)PCP)Ni-OMe] affords polynuclear carbonyl phosphine complexes. Both decomposition processes are initiated by β-hydrogen elimination (BHE), but the resulting [((iPr)PCP)M-H] hydrides undergo divergent reaction sequences that ultimately lead to the irreversible breakdown of the pincer units. Whereas the Pd hydride spontaneously experiences reductive C-H coupling, the decay of its Ni analogue is brought about by its reaction with formaldehyde released in the BHE step. Kinetic measurements showed that the BHE reaction is reversible and less favourable for Ni than for Pd for both kinetic and thermodynamic reasons. DFT calculations confirmed the main conclusions of the kinetic studies and provided further insight into the mechanisms of the decomposition reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. On the corrosion behavior and biocompatibility of palladium-based dental alloys

    Science.gov (United States)

    Sun, Desheng

    Palladium-based alloys have been used as dental restorative materials for about two decades with good clinical history. But there have been clinical case reports showing possible allergy effects from these alloys. The aim of this study was to characterize the corrosion behavior and mechanisms of several palladium-based dental alloys by potentiodynamic polarization methods, electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe force microscopy/atomic force microscopy (SKPFM/AFM), and to evaluate their biocompatibility by a cell culture technique and an animal model. Using SKPFM/AFM and scanning electron microscopy, the Ru-enriched phase from the use of ruthenium as a grain-refining element was identified as being slightly more noble than the palladium solid solution matrix in a high-palladium alloy. Other secondary precipitates that exist in the microstructures of these high-palladium alloys have minimal differences in Volta potential compared to the matrix. For high-palladium alloys, corrosion is generally uniform due to the predominant palladium content in the different phases. Potentiodynamic polarization and EIS have shown that representative palladium-silver alloys have low corrosion tendency and high corrosion resistance, which are equivalent to a well-known high-noble gold-palladium alloy in simulated body fluid and oral environments. The palladium-silver alloys tested are resistant to chloride ion corrosion. Passivation and dealloying have been identified for all of the tested palladium-silver alloys. The great similarity in corrosion behavior among the palladium-silver alloys is attributed to their similar chemical compositions. The variation in microstructures of palladium-silver alloys tested does not cause significant difference in corrosion behavior. The corrosion resistance of these palladium-silver alloys at elevated potentials relevant to oral environment is still satisfactory. The release of elements from representative dental

  8. Incidence of platinum-induced ototoxicity in pediatric patients in Quebec.

    Science.gov (United States)

    Peleva, Emilia; Emami, Nader; Alzahrani, Mohammad; Bezdjian, Aren; Gurberg, Joshua; Carret, Anne-Sophie; Daniel, Sam J

    2014-11-01

    The antineoplastic agents cisplatin and carboplatin are widely-used and highly-effective against a variety of pediatric cancers. Unfortunately, ototoxicity is a frequently encountered side effect of platinum-based chemotherapy. There is currently no treatment or prevention for platinum-induced ototoxicity and development of hearing loss may lead to devastating consequences on the quality of life of pediatric cancer survivors. The objective of this study is to determine the incidence of platinum-induced ototoxicity in a large series of pediatric patients and to evaluate the incidence of progression of ototoxicity after completion of treatment. A retrospective chart review of pediatric patients treated with cisplatin or carboplatin between 2000 and 2012 was conducted. The incidence of ototoxicity was determined based on the American-Speech-Language-Hearing Association (ASHA) criteria and severity was based on the Chang classification. Four hundred and sixty-six patients received platinum-based chemotherapy. Patients were excluded due to congenital hearing loss (n = 1) and insufficient data for calculating the platinum dose (n = 24) or for assessing ototoxicity (n = 135). Three hundred and six patients were included in the analysis. Post-chemotherapy ototoxicity was detected in 148 (48%) patients, and clinically-significant ototoxicity was present in 91 (30%). In addition, based on the ASHA criteria, 48% of patients (97/204) with long-term follow-up had further deterioration of their hearing after completion of treatment. Ototoxicity following chemotherapy with cisplatin or carboplatin is common and can frequently progress after the completion of treatment. Long-term follow-up is strongly recommended. © 2014 Wiley Periodicals, Inc.

  9. Remarkable NO oxidation on single supported platinum atoms.

    Science.gov (United States)

    Narula, Chaitanya K; Allard, Lawrence F; Stocks, G M; Moses-DeBusk, Melanie

    2014-11-28

    Our first-principles density functional theoretical modeling suggests that NO oxidation is feasible on fully oxidized single θ-Al2O3 supported platinum atoms via a modified Langmuir-Hinshelwood pathway. This is in contrast to the known decrease in NO oxidation activity of supported platinum with decreasing Pt particle size believed to be due to increased platinum oxidation. In order to validate our theoretical study, we evaluated single θ-Al2O3 supported platinum atoms and found them to exhibit remarkable NO oxidation activity. A comparison of turnover frequencies (TOF) of single supported Pt atoms with those of platinum particles for NO oxidation shows that single supported Pt atoms are as active as fully formed platinum particles. Thus, the overall picture of NO oxidation on supported Pt is that NO oxidation activity decreases with decreasing Pt particle size but accelerates when Pt is present only as single atoms.

  10. Synthesis of Bimetallic Platinum Nanoparticles for Biosensors

    Directory of Open Access Journals (Sweden)

    Gerard M. Leteba

    2013-08-01

    Full Text Available The use of magnetic nanomaterials in biosensing applications is growing as a consequence of their remarkable properties; but controlling the composition and shape of metallic nanoalloys is problematic when more than one precursor is required for wet chemistry synthesis. We have developed a successful simultaneous reduction method for preparation of near-spherical platinum-based nanoalloys containing magnetic solutes. We avoided particular difficulties in preparing platinum nanoalloys containing Ni, Co and Fe by the identification of appropriate synthesis temperatures and chemistry. We used transmission electron microscopy (TEM to show that our particles have a narrow size distribution, uniform size and morphology, and good crystallinity in the as-synthesized condition. Energy dispersive spectroscopy (EDS and X-ray diffraction (XRD confirms the coexistence of Pt with the magnetic solute in a face-centered cubic (FCC solid solution.

  11. Catalytic converters as a source of platinum

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2011-10-01

    Full Text Available The increase of Platinum Group Metals demand in automotive industry is connected with growing amount of cars equipped with the catalytic converters. The paper presents the review of available technologies during recycling process. The possibility of removing platinum from the used catalytic converters applying pyrometallurgical and hyrdometallurgical methods were also investigated. Metals such as Cu, Pb, Ca, Mg, Cd were used in the pyrometallurgical research (catalytic converter was melted with Cu, Pb and Ca or Mg and Cd vapours were blown through the whole carrier. In hydrometallurgical research catalytic converters was dissolved in aqua regia. Analysis of Pt contents in the carrier before and after the process was performed by means of atomic absorption spectroscopy. Obtained result were discussed.

  12. Phyto-crystallization of palladium through reduction process using Cinnamom zeylanicum bark extract

    Energy Technology Data Exchange (ETDEWEB)

    Sathishkumar, M.; Sneha, K.; Kwak, In Seob; Mao, Juan [Environmental Biotechnology National Research Laboratory, School of Chemical Engineering, Research Institute of Industrial Technology, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Tripathy, S.J. [Nanoparticulate Materials Laboratory, Division of Advanced Materials Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Yun, Y.-S., E-mail: ysyun@chonbuk.ac.kr [Environmental Biotechnology National Research Laboratory, School of Chemical Engineering, Research Institute of Industrial Technology, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

    2009-11-15

    In this paper we studied the potential of nanocrystalline palladium particle production using Cinnamom zeylanicum bark extract (CBE) as the biomaterial for the first time. We studied the effects of biomaterial dosage, pH and temperature on nanoparticle formation; none of these factors had a major effect on the size and shape of the nanoparticles formed. Transmission electron microscopy (TEM) observations confirmed the synthesis of nano-sized palladium particles. More or less uniformly sized palladium nanoparticles were synthesized with an average size ranging from 15 to 20 nm. It was found that the zeta potential of these formed palladium nanoparticles was negative, and that it increased with an increase in pH. Energy dispersive X-ray (EDX) analysis results confirmed the significant presence of palladium. Of the palladium ions, 60% were reduced to a zero valent form by CBE. Terpenoids are believed to play an important role in palladium nanoparticle biosynthesis through the reduction of palladium ions. Currently, however, the exact mechanism for the synthesis of palladium nanoparticles is unclear. Our protocol for the phyto-synthesis of palladium nanoparticles under moderate pH and room temperature offers a new means to develop environmentally benign nanoparticles.

  13. Biological evaluation of a novel Herceptin-platinum (II) conjugate for efficient and cancer cell specific delivery.

    Science.gov (United States)

    Huang, Rong; Sun, Yu; Zhang, Xiang-yang; Sun, Bai-wang; Wang, Qiu-cui; Zhu, Jin

    2015-07-01

    Platinum-based drugs have been widely used for the treatment of malignant tumors. However, their applications are limited by severe side effects for their lack of selectivity for cancer cells. The development of antibody drug conjugates (ADCs) have provided a platform to reduce drug toxicity and improve drug efficacy. Here we describe a nover conjugate comprising of Herceptin (an anti-HER2 antibody) and platinum drug via a cathepsin B cleavable dipetide for enhancing drug accumulation and HER2-positive cancer cell specific delivery. This conjugate is believed to be cleaved by cathepsin B, leading to a 1,6-elimination reaction and activation of drug release. Herceptin-Pt(II) is evaluated to have approximately loaded with 6.4 moles platinum drugs per mole of antibody. We demonstrate that Herceptin-Pt(II) retain high and selective binding affinity for HER2 protein and HER2-positive SK-BR-3 cancer cells. The in vitro cytotoxicity tests indicate that Herceptin-Pt(II) exhibits much higher cytotoxicity than oxaliplatin against SK-BR-3 cells. More importantly, Herceptin-Pt(II) shows no obvious inhibition against the growth of both MCF-7 and MDA-MB-231 cells, which express lower levels of HER2. Furthermore, compared with free oxaliplatin, Herceptin significantly improved the cellular uptake of platinum drugs in SK-BR-3 cells. In summary, Herceptin-platinum (II) conjugate is a remarkable and potent platform for efficient and cancer cell specific delivery.

  14. Stability of Porous Platinum Nanoparticles: Combined In Situ TEM and Theoretical Study

    DEFF Research Database (Denmark)

    Chang, Shery L. Y.; Barnard, Amanda S.; Dwyer, Christian

    2012-01-01

    Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first...

  15. Palladium catalyzed heck arylation of 2,3-dihydrofuran-effect of the palladium precursor.

    Science.gov (United States)

    Morel, Adam; Trzeciak, Anna M; Pernak, Juliusz

    2014-06-19

    Heck arylation of 2,3-dihydrofuran with iodobenzene was carried out in systems consisting of different palladium precursors (Pd2(dba)3, Pd(acac)2, PdCl2(cod), [PdCl(allyl)]2, PdCl2(PhCN)2, PdCl2(PPh3)2) and ionic liquids (CILs) with L-prolinate or L-lactate anions. All the tested CILs caused remarkable increases of the conversion values and in all of the reactions 2-phenyl-2,3-dihydrofuran (3) was obtained as the main product with a yield of up to 59.2%. The highest conversions of iodobenzene were achieved for the [PdCl(allyl)]2 precursor. Formation of Pd(0) nanoparticles, representing the resting state of the catalyst, was evidenced by TEM.

  16. Palladium Catalyzed Heck Arylation of 2,3-Dihydrofuran—Effect of the Palladium Precursor

    Directory of Open Access Journals (Sweden)

    Adam Morel

    2014-06-01

    Full Text Available Heck arylation of 2,3-dihydrofuran with iodobenzene was carried out in systems consisting of different palladium precursors (Pd2(dba3, Pd(acac2, PdCl2(cod, [PdCl(allyl]2, PdCl2(PhCN2, PdCl2(PPh32 and ionic liquids (CILs with L-prolinate or L-lactate anions. All the tested CILs caused remarkable increases of the conversion values and in all of the reactions 2-phenyl-2,3-dihydrofuran (3 was obtained as the main product with a yield of up to 59.2%. The highest conversions of iodobenzene were achieved for the [PdCl(allyl]2 precursor. Formation of Pd(0 nanoparticles, representing the resting state of the catalyst, was evidenced by TEM.

  17. Redeposition of electrochemically dissolved platinum as nanoparticles on carbon

    DEFF Research Database (Denmark)

    Norgaard, C. F.; Stamatin, S. N.; Skou, E. M.

    2014-01-01

    Electrochemical dissolution of platinum has been proposed by several research groups as an environmentally friendly way to recover platinum from catalytic structures such as fuel cell electrodes. For the case of electrochemical dissolution of platinum in hydrochloric acid electrolyte, the present...... on carbon was then identified, quantified, and the particle size evaluated by powder X-ray diffraction, thermogravimetric analysis and cyclic voltammetry. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved....

  18. Synthesis of novel photochromic pyrans via palladium-mediated reactions

    NARCIS (Netherlands)

    Böttcher, Christoph; Zeyat, Gehad; Ahmed, Saleh A.; Irran, Elisabeth; Cordes, Thorben; Elsner, Cord; Zinth, Wolfgang; Rueck-Braun, Karola

    2009-01-01

    Photochromic pyrans for applications in material and life sciences were synthesized via palladium-mediated cyanation, carbonylation and Sonogashira cross-coupling starting from a bromo-substituted naphthopyran and benzopyrans. A novel photoswitchable benzopyran-based ω-amino acid for Fmoc-based soli

  19. Direct acylation of aryl bromides with aldehydes by palladium catalysis.

    Science.gov (United States)

    Ruan, Jiwu; Saidi, Ourida; Iggo, Jonathan A; Xiao, Jianliang

    2008-08-13

    A new protocol for the direct acylation of aryl bromides with aldehydes is established. It appears to involve palladium-amine cooperative catalysis, affording synthetically important alkyl aryl ketones in moderate to excellent yields in a straightforward manner, and broadening the scope of metal-catalyzed coupling reactions.

  20. Exposure to nickel and palladium from dental appliances

    NARCIS (Netherlands)

    Ventura Da Cruz Rodrigues Milheiro, A.M.

    2015-01-01

    The application of a dental material into the oral cavity is not free of biological implications, as deterioration of the material will undoubtedly occur. The adverse health effects of palladium and nickel are well known and their immunologic cross-reactivity is well established. The aim of this the

  1. Biotemplated fabrication of size controlled palladium nanoparticle chains

    NARCIS (Netherlands)

    Zhou, Xingfei; Zheng, Lifei; Li, Rong; Li, Bin; Pillai, Saju; Xu, Peng; Zhang, Yi

    2012-01-01

    Metal nanoparticles exhibit unique size- and spatial organization-dependent physical and chemical properties, and have a wide range of applications in various areas including single electron devices, chemical catalysts and biomedicines. In this paper, chains of palladium nanoparticles were obtained

  2. Palladium-Catalyzed Carboxylation of Activated Vinylcyclopropanes with CO2.

    Science.gov (United States)

    Mita, Tsuyoshi; Tanaka, Hiroyuki; Higuchi, Yuki; Sato, Yoshihiro

    2016-06-01

    By using a palladium catalyst with ZnEt2, activated vinylcyclopropanes were successfully converted into the corresponding β,γ-unsaturated carboxylic acids in high yields under a CO2 atmosphere (1 atm). The intermediate in this reaction is thought to be a nucleophilic η(1)-allylethylpalladium species, which would be produced from π-allylpalladium and ZnEt2 (umpolung reactivity).

  3. Palladium-Catalyzed alpha-Arylation of Tetramic Acids

    DEFF Research Database (Denmark)

    Storgaard, Morten; Dorwald, F. Z.; Peschke, B.;

    2009-01-01

    A mild, racemization-free, palladium-Catalyzed alpha-arylation of tetramic acids (2,4-pyrrolidinediones) has been developed. Various amino acid-derived tetramic acids were cleanly arylated by treatment with 2 mol % of Pd(OAc)(2), 4 mol % of a sterically demanding biaryl phosphine, 2.3 equiv of K2CO...

  4. Hydrogen storage studies of palladium decorated nitrogen doped graphene nanoplatelets.

    Science.gov (United States)

    Vinayan, B P; Sethupathi, K; Ramaprabhu, S

    2012-08-01

    Hydrogen storage in materials is of significant importance in the present scenario of depleting conventional energy sources. Porous solids such as activated carbon or nanostructured carbon materials have promising future as hydrogen storage media. The hydrogen storage capacity in nanostructured carbon materials can be further enhanced by atomic hydrogen spillover from a supported catalyst. In the present work, the hydrogen storage properties of nitrogen doped graphene nanoplatelets (N-GNP) and palladium decorated nitrogen doped graphene nanoplatelets (Pd/N-GNP) have been investigated. The results show that hydrogen uptake capacity of nitrogen doped graphene nanoplatelets and palladium decorated nitrogen doped graphene nanoplatelets at pressure 32 bar and temperature 25 degrees C is 0.42 wt% and 1.25 wt% respectively. The dispersion of palladium nanoparticles increases the hydrogen storage capacity of nitrogen doped graphene nanoplatelets by 0.83 wt%. This may be due to high dispersion of palladium nanoparticles and strong adhesion between metal and graphene nanoplatelets over the surface of N-GNP, which enhances the spillover mechanism. Thus, an increase in the hydrogen spillover effect and the binding energy between metal nanoparticles and supporting material achieved by nitrogen doping has been observed to result in a higher hydrogen storage capacity of pristine GNP.

  5. Ultralow-power hydrogen sensing with single palladium nanowires

    NARCIS (Netherlands)

    Offermans, P.; Tong, H.D.; Rijn, C.J.M. van; Merken, P.; Brongersma, S.H.; Crego-Calama, M.

    2009-01-01

    Palladium nanowires were fabricated on silicon substrates using conventional microfabrication techniques. Sensors based on such nanowires show a reversible response to hydrogen concentrations as low as 27 ppm with response times varying from 5 s (H2 concentrations >20%) to 30 s (H2 concentrations <1

  6. Palladium-catalyzed silylation of aryl chlorides with hexamethyldisilane.

    Science.gov (United States)

    McNeill, Eric; Barder, Timothy E; Buchwald, Stephen L

    2007-09-13

    A method for the palladium-catalyzed silylation of aryl chlorides has been developed. The method affords desired product in good yield, is tolerant of a variety of functional groups, and provides access to a wide variety of aryltrimethylsilanes from commercially available aryl chlorides. Additionally, a one-pot procedure that converts aryl chlorides into aryl iodides has been developed.

  7. STRONTIUM AS AN EFFICIENT PROMOTER FOR SUPPORTED PALLADIUM HYDROGENATION CATALYSTS

    Science.gov (United States)

    The effect of strontium promotion is studied for a series of supported palladium catalysts such as Pd/zeolite-β, Pd/Al2O3, Pd/SiO2, Pd/hydrotalcite and Pd/MgO. Strontium is found to be an effective promoter for enhancing the metal area, perce...

  8. Catalytic removal of carbon monoxide over carbon supported palladium catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Avanish Kumar [Defence Research and Development Establishment, Jhansi Road, Gwalior-474002 (MP) (India); Saxena, Amit [Centre for Fire Explosive and Environmental Safety, Timarpur, Delhi-110054 (India); Shah, Dilip; Mahato, T.H. [Defence Research and Development Establishment, Jhansi Road, Gwalior-474002 (MP) (India); Singh, Beer, E-mail: beerbs5@rediffmail.com [Defence Research and Development Establishment, Jhansi Road, Gwalior-474002 (MP) (India); Shrivastava, A.R.; Gutch, P.K. [Defence Research and Development Establishment, Jhansi Road, Gwalior-474002 (MP) (India); Shinde, C.P. [School of Studies in Chemistry, Jiwaji University, Gwalior-474002 (MP) (India)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Carbon supported palladium (Pd/C) catalyst was prepared. Black-Right-Pointing-Pointer Catalytic removal of CO over Pd/C catalyst was studied under dynamic conditions. Black-Right-Pointing-Pointer Effects of Pd %, CO conc., humidity, GHSV and reaction environment were studied. - Abstract: Carbon supported palladium (Pd/C) catalyst was prepared by impregnation of palladium chloride using incipient wetness technique, which was followed by liquid phase reduction with formaldehyde. Thereafter, Pd/C catalyst was characterized using X-ray diffractometery, scanning electron microscopy, atomic absorption spectroscopy, thermo gravimetry, differential scanning calorimetry and surface characterization techniques. Catalytic removal of carbon monoxide (CO) over Pd/C catalyst was studied under dynamic conditions. Pd/C catalyst was found to be continuously converting CO to CO{sub 2} through the catalyzed reaction, i.e., CO + 1/2O{sub 2} {yields} CO{sub 2}. Pd/C catalyst provided excellent protection against CO. Effects of palladium wt%, CO concentration, humidity, space velocity and reaction environment were also studied on the breakthrough behavior of CO.

  9. Palladium nanoparticle-based surface acoustic wave hydrogen sensor.

    Science.gov (United States)

    Sil, Devika; Hines, Jacqueline; Udeoyo, Uduak; Borguet, Eric

    2015-03-18

    Palladium (Pd) nanoparticles (5-20 nm) are used as the sensing layer on surface acoustic wave (SAW) devices for detecting H2. The interaction with hydrogen modifies the conductivity of the Pd nanoparticle film, producing measurable changes in acoustic wave propagation, which allows for the detection of this explosive gas. The nanoparticle-based SAW sensor responds rapidly and reversibly at room temperature.

  10. Silver-palladium braze alloy recovered from masking materials

    Science.gov (United States)

    Cierniak, R.; Colman, G.; De Carlo, F.

    1966-01-01

    Method for recovering powdered silver-palladium braze alloy from an acrylic spray binder and rubber masking adhesive used in spray brazing is devised. The process involves agitation and dissolution of masking materials and recovery of suspended precious metal particles on a filter.

  11. Palladium catalyzed C3-arylation of 4-hydroxy-2-pyridones.

    Science.gov (United States)

    Anagnostaki, Elissavet E; Fotiadou, Anna D; Demertzidou, Vera; Zografos, Alexandros L

    2014-07-01

    The direct arylation of N-substituted-4-hydroxy-2-pyridones with aryl boronic acids has been achieved under palladium catalysis. The mild reaction conditions applied in this method and the use of a conventional catalytic system offer an attractive protocol for the efficient synthesis of a variety of 3-arylated products.

  12. Palladium-catalyzed enantioselective conjugate addition of arylboronic acids

    NARCIS (Netherlands)

    Gini, F; Hessen, B; Minnaard, AJ

    2005-01-01

    The first asymmetric palladium-catalyzed conjugate addition of arylboronic acids to alpha,beta-unsaturated aldehydes, ketones, and esters is described. For cyclic substrates, excellent chemo-, regio-, and enantioselectivities are achieved when a Pd(O2CCF3)(2)/DuPHOS catalyst is applied.

  13. Platinum germanium ordering in UPtGe

    Science.gov (United States)

    Hoffmann, Rolf-Dieter; Pöttgen, Rainer; Lander, Gerry H.; Rebizant, Jean

    2001-09-01

    The non-centrosymmetric structure of UPtGe was investigated by X-ray diffraction on both powders and single crystals: EuAuGe type, Imm2, a=432.86(5), b=718.81(8), c=751.66(9) pm, wR2=0.0738 for 399 F2 values and 22 variables. The platinum and germanium atoms form two-dimensional layers of puckered Pt 3Ge 3 hexagons with short PtGe intralayer distances of 252 and 253 pm. These condensed two-dimensionally infinite nets are interconnected to each other via weak PtPt contacts with bond distances of 300 pm. The two crystallographically independent uranium atoms are situated above and below the six-membered platinum-germanium rings. The U1 atoms have six closer germanium neighbors while the U2 atoms have six closer platinum neighbors. The group-subgroup relation with the KHg 2 type structure is presented.

  14. Electrodeposition of Palladium and Adsorption of Palladium Chloride onto Solid Electrodes from Room Temperature Molten Salts

    Science.gov (United States)

    1994-04-01

    electrolytes.’" Here, we ex- For all electrochemical experiments, the counterelec- * Electrochemical Society Active Member. trode was a platinum foil, and...4, April 1994 © The Electrochemical Society , Inc. 1001 sisted of Al wire immersed in either an N= 0.67 or N = 0.60 IE-05 ...... . . AICI2-MEJC melt...indicate the movement of the reduction wave to more 10(d2 - J. Electrochem. Soc., Vol. 141, No. 4, April 1994 © The Electrochemical Society , Inc. 3.OOE-05 1

  15. Preparation and Electrochemical Properties of Porous Platinum Electrode

    Institute of Scientific and Technical Information of China (English)

    HE Xin; CHEN Boxun; CHEN Qiao

    2012-01-01

    Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O2(g)/Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.

  16. Controlled synthesis of porous platinum nanostructures for catalytic applications.

    Science.gov (United States)

    Cao, Yanqin; Zhang, Junwei; Yang, Yong; Huang, Zhengren; Long, Nguyen Viet; Nogami, Masayuki

    2014-02-01

    Porous platinum, that has outstanding catalytic and electrical properties and superior resistant characteristics to corrosion, has been widely applied in chemical, petrochemical, pharmaceutical, electronic, and automotive industries. As the catalytic activity and selectivity depend on the size, shape and structure of nanomaterials, the strategies for controlling these factors of platinum nanomaterials to get excellent catalytic properties are discussed. Here, recent advances in the design and preparation of various porous platinum nanostructures are reviewed, including wet-chemical synthesis, electro-deposition, galvanic replacement reaction and de-alloying technology. The applications of various platinum nanostructures are also discussed, especially in fuel cells.

  17. Activity of phosphino palladium(II) and platinum(II) complexes against HIV-1 and Mycobacterium tuberculosis.

    Science.gov (United States)

    Gama, Ntombenhle H; Elkhadir, Afag Y F; Gordhan, Bhavna G; Kana, Bavesh D; Darkwa, James; Meyer, Debra

    2016-08-01

    Treatment of human immunodeficiency virus (HIV) is currently complicated by increased prevalence of co-infection with Mycobacterium tuberculosis. The development of drug candidates that offer the simultaneous management of HIV and tuberculosis (TB) would be of great benefit in the holistic treatment of HIV/AIDS, especially in sub-Saharan Africa which has the highest global prevalence of HIV-TB coinfection. Bis(diphenylphosphino)-2-pyridylpalladium(II) chloride (1), bis(diphenylphosphino)-2-pyridylplatinum(II) chloride (2), bis(diphenylphosphino)-2-ethylpyridylpalladium(II) chloride (3) and bis(diphenylphosphino)-2-ethylpyridylplatinum(II) (4) were investigated for the inhibition of HIV-1 through interactions with the viral protease. The complexes were subsequently assessed for biological potency against Mycobacterium tuberculosis H37Rv by determining the minimal inhibitory concentration (MIC) using broth microdilution. Complex (3) showed the most significant and competitive inhibition of HIV-1 protease (p = 0.014 at 100 µM). Further studies on its in vitro effects on whole virus showed reduced viral infectivity by over 80 % at 63 µM (p < 0.05). In addition, the complex inhibited the growth of Mycobacterium tuberculosis at an MIC of 5 µM and was non-toxic to host cells at all active concentrations (assessed by tetrazolium dye and real time cell electronic sensing). In vitro evidence is provided here for the possibility of utilizing a single metal-based compound for the treatment of HIV/AIDS and TB.

  18. Platinum and palladium emissions from on-road vehicles in the Kaisermühlen Tunnel (Vienna, Austria).

    Science.gov (United States)

    Limbeck, Andreas; Puls, Christoph; Handler, Markus

    2007-07-15

    Total and size-segregated Pt and Pd emission factors from on-road vehicles were measured in the Kaisermühlen Tunnel in Vienna, Austria. Aerosol sampling was performed simultaneously inside and outside the tunnel during April and May 2005. Analysis of the acid-digested aerosol samples was performed using a preconcentration procedure with subsequent on-line detection by electro-thermal atomic absorption spectrometry (ETAAS). Inside the tunnel distinctly increased Pt and Pd concentrations were found with highest levels in total suspended particulate matter samples and reduced concentrations in the size-segregated PM10 and PM2.5 samples. Emission factors were calculated from concentration differences between tunnel inside and tunnel outside samples, the distance between tunnel entrance and sampling location, the ventilation rate, and the number of vehicles passing through the tunnel. Emission rates observed for Pt ranged from 38 +/- 5.9 to 146 +/- 13 ng veh(-1) km(-1), whereas the emission factors of Pd varied between 13 +/- 2.1 and 42 +/- 4.1 ng veh(-1) km(-1). Variations in the emission rates were assumed to originate from alterations in traffic conditions. Size-segregated investigations revealed that the major part of Pt and Pd emissions were released in the coarse aerosol mode (size fraction > PM10), nevertheless a considerable fraction (approximately 12% and approximately 22% respectively) was emitted in the inhalable PM2.5 fraction.

  19. Mechanism of pH-switchable peroxidase and catalase-like activities of gold, silver, platinum and palladium.

    Science.gov (United States)

    Li, Junnan; Liu, Wenqi; Wu, Xiaochun; Gao, Xingfa

    2015-04-01

    Despite being increasingly used as artificial enzymes, little has been known for the origin of the pH-switchable peroxidase-like and catalase-like activities of metals. Using calculations and experiments, we report the mechanisms for both activities and their pH-switchability for metals Au, Ag, Pd and Pt. The calculations suggest that both activities are intrinsic properties of metals, regardless of the surfaces and intersections of facets exposed to environments. The pre-adsorbed OH groups on the surfaces, which are only favorably formed in basic conditions, trigger the switch between both activities and render the pH-switchability. The adsorption energies between H2O2 and metals can be used as convenient descriptors to predict the relative enzyme-like activities of the metals with similar surface morphologies. The results agree with the enzyme-mimic activities that have been experimentally reported for Au, Ag, Pt and predict that Pd should have the similar properties. The prediction, as well as the predicted activity order for the four metals, has been verified by the experimental tests. The results thus provide an in-depth insight into the peroxidase-like and catalase-like activities of the metals and will guide the de novo design, synthesis and application of artificial enzymes based on inorganic materials.

  20. Palladium(II) and platinum(II) complexes containing benzimidazole ligands: Molecular structures, vibrational frequencies and cytotoxicity

    Science.gov (United States)

    Abdel Ghani, Nour T.; Mansour, Ahmed M.

    2011-04-01

    (1H-benzimidazol-2-ylmethyl)-(4-methoxyl-phenyl)-amine (L 1), (1H-benzimidazol-2-ylmethyl)-(4-methyl-phenyl)-amine (L 2) and their Pd(II) and Pt(II) complexes have been synthesized as potential anticancer compounds and their structures were elucidated using a variety of physico-chemical techniques. Theoretical calculations invoking geometry optimization, vibrational assignments, 1H NMR, charge distribution and molecular orbital description HOMO and LUMO were done using density functional theory. Natural bond orbital analysis (NBO) method was performed to provide details about the type of hybridization and the nature of bonding in the studied complexes. Strong coordination bonds (LP(1)N11 → σ *(M sbnd Cl22)) and (LP(1)N21 → σ *(M sbnd Cl23)) (M = Pd or Pt) result from donation of electron density from a lone pair orbital on the nitrogen atoms to the acceptor metal molecular orbitals. The experimental results and the calculated molecular parameters revealed square-planar geometries around the metallic centre through the pyridine-type nitrogen of the benzimidazole ring and secondary amino group and two chlorine atoms. The activation thermodynamic parameters were calculated using non-isothermal methods. The synthesized ligands, in comparison to their metal complexes were screened for their antibacterial activity. In addition, the studied complexes showed activity against three cell lines of different origin, breast cancer (MCF-7), Colon Carcinoma (HCT) and human heptacellular carcinoma (Hep-G2) comparable to cis-platin.

  1. Adsorption of platinum(IV) and palladium(II) from aqueous solution by thiourea-modified chitosan microspheres.

    Science.gov (United States)

    Zhou, Limin; Liu, Jinhui; Liu, Zhirong

    2009-12-15

    The chitosan microparticles were prepared using the inverse phase emulsion dispersion method and modified with thiourea (TCS). TCS was characterized by scanning electron microscope (SEM), the Fourier transform infrared (FT-IR) spectra, sulfur elemental analysis, specific surface area and pore diameter. The effects of various parameters, such as pH, contact time, initial concentration and temperature, on the adsorption of Pt(IV) and Pd(II) by TCS were investigated. The results showed that the maximum adsorption capacity was found at pH 2.0 for both Pt(IV) and Pd(II). TCS can selectively adsorb Pt(IV) and Pd(II) from binary mixtures with Cu(II), Pb(II), Cd(II), Zn(II), Ca(II), and Mg(II). The adsorption reaction followed the pseudo-second-order kinetics, indicating the main adsorption mechanism of chemical adsorption. The isotherm adsorption equilibrium was well described by Langmuir isotherms with the maximum adsorption capacity of 129.9 mg/g for Pt(IV) and 112.4 mg/g for Pd(II). The adsorption capacity of both Pt(IV) and Pd(II) decreased with temperature increasing. The negative values of enthalpy (DeltaH degrees ) and Gibbs free energy (DeltaG degrees ) indicate that the adsorption process is exothermic and spontaneous in nature. The adsorbent was stable without loss of the adsorption capacity up to at least 5 cycles and the desorption efficiencies were above 95% when 0.5 M EDTA-0.5M H2SO4 eluent was used. The results also showed that the preconcentration factor for Pt(IV) and Pd(II) was 196 and 172, respectively, and the recovery was found to be more than 97% for both precious metal ions.

  2. Structures and magnetism of mono-palladium and mono-platinum doped Au25(PET)18 nanoclusters.

    Science.gov (United States)

    Tian, Shubo; Liao, Lingwen; Yuan, Jinyun; Yao, Chuanhao; Chen, Jishi; Yang, Jinlong; Wu, Zhikun

    2016-08-01

    Herein we report three important results of widespread interest, which are (1) the crystal structure of [Au24Pt(PET)18](0), (2) the crystal structure of [Au24Pd(PET)18](0) and (3) the main source of magnetism in [Au25(PET)18](0).

  3. Activity of platinum/carbon and palladium/carbon catalysts promoted by Ni2 P in direct ethanol fuel cells.

    Science.gov (United States)

    Li, Guoqiang; Feng, Ligang; Chang, Jinfa; Wickman, Björn; Grönbeck, Henrik; Liu, Changpeng; Xing, Wei

    2014-12-01

    Ethanol is an alternative fuel for direct alcohol fuel cells, in which the electrode materials are commonly based on Pt or Pd. Owing to the excellent promotion effect of Ni2 P that was found in methanol oxidation, we extended the catalyst system of Pt or Pd modified by Ni2 P in direct ethanol fuel cells. The Ni2 P-promoted catalysts were compared to commercial catalysts as well as to reference catalysts promoted with only Ni or only P. Among the studied catalysts, Pt/C and Pd/C modified by Ni2 P (30 wt %) showed both the highest activity and stability. Upon integration into the anode of a homemade direct ethanol fuel cell, the Pt-Ni2 P/C-30 % catalyst showed a maximum power density of 21 mW cm(-2) , which is approximately two times higher than that of a commercial Pt/C catalyst. The Pd-Ni2 P/C-30 % catalyst exhibited a maximum power density of 90 mW cm(-2) . This is approximately 1.5 times higher than that of a commercial Pd/C catalyst. The discharge stability on both two catalysts was also greatly improved over a 12 h discharge operation.

  4. Synthesis of Benzo[c]silole Derivatives Bearing a Tetrasubstituted Exocyclic C=C Double Bond by Palladium-Catalyzed Domino Reactions.

    Science.gov (United States)

    Wagner, Patrick; Gulea, Mihaela; Suffert, Jean; Donnard, Morgan

    2017-06-01

    The synthesis of diversely substituted 2,3-dihydro-benzo[c]siloles through an unprecedented palladium-catalyzed domino sequence is reported, involving a cyclocarbopalladation of an internal silylalkyne. This reaction proceeds with complete stereoselectivity to lead to a fully substituted exocyclic C=C double bond. Notably, the overall domino sequence appears to be crucial to obtain the desired cyclic vinylsilanes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. How much platinum passes the placental barrier? Analysis of platinum applications in 21 patients with cervical cancer during pregnancy.

    Science.gov (United States)

    Köhler, Christhardt; Oppelt, Peter; Favero, Giovanni; Morgenstern, Bernd; Runnebaum, Ingo; Tsunoda, Audrey; Schmittel, Alexander; Schneider, Achim; Mueller, Michael; Marnitz, Simone

    2015-08-01

    Cervical cancer is the most common solid cancer diagnosed in pregnancy. Platinum is an active drug in the treatment of patients with cervical cancer. In the second and third trimesters, platinum is used to prevent cancer progression until fetal maturity is reached. However, knowledge about the transplacental passage of platinum is very limited. Between May 2008 and June 2014, platinum-based neoadjuvant chemotherapy was applied to 21 consecutive patients with cervical cancer diagnosed in their second trimester. At the time of delivery by cesarean delivery, synchronous samples from maternal blood, umbilical cord blood, and amniotic fluid were taken and analyzed for platinum concentrations. The mean week of gestation at cancer diagnosis was 17 (13-23). On average 3 (range, 2-4) cycles of chemotherapy were applied. Cesarean deliveries were carried out between 30.4 and 36.5 weeks of gestation. Twenty-two healthy babies without renal, hepatic, auditory, or hematopoietic impairment were delivered. Platinum concentrations in umbilical cord blood and amniotic fluid were 23-65% and 11-42% of the maternal blood, respectively. This series on in vivo measurement of platinum concentrations in the fetomaternal compartment observed that because of consistently lower platinum values in the fetoplacental unit, a placental filtration mechanism of platinum may be assumed. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Fexofenadine Suppresses Delayed-Type Hypersensitivity in the Murine Model of Palladium Allergy

    Science.gov (United States)

    Matsubara, Ryota; Kumagai, Kenichi; Shigematsu, Hiroaki; Kitaura, Kazutaka; Nakasone, Yasunari; Suzuki, Satsuki; Hamada, Yoshiki; Suzuki, Ryuji

    2017-01-01

    Palladium is frequently used in dental materials, and sometimes causes metal allergy. It has been suggested that the immune response by palladium-specific T cells may be responsible for the pathogenesis of delayed-type hypersensitivity in study of palladium allergic model mice. In the clinical setting, glucocorticoids and antihistamine drugs are commonly used for treatment of contact dermatitis. However, the precise mechanism of immune suppression in palladium allergy remains unknown. We investigated inhibition of the immune response in palladium allergic mice by administration of prednisolone as a glucocorticoid and fexofenadine hydrochloride as an antihistamine. Compared with glucocorticoids, fexofenadine hydrochloride significantly suppressed the number of T cells by interfering with the development of antigen-presenting cells from the sensitization phase. Our results suggest that antihistamine has a beneficial effect on the treatment of palladium allergy compared to glucocorticoids. PMID:28672829

  7. Fexofenadine Suppresses Delayed-Type Hypersensitivity in the Murine Model of Palladium Allergy

    Directory of Open Access Journals (Sweden)

    Ryota Matsubara

    2017-06-01

    Full Text Available Palladium is frequently used in dental materials, and sometimes causes metal allergy. It has been suggested that the immune response by palladium-specific T cells may be responsible for the pathogenesis of delayed-type hypersensitivity in study of palladium allergic model mice. In the clinical setting, glucocorticoids and antihistamine drugs are commonly used for treatment of contact dermatitis. However, the precise mechanism of immune suppression in palladium allergy remains unknown. We investigated inhibition of the immune response in palladium allergic mice by administration of prednisolone as a glucocorticoid and fexofenadine hydrochloride as an antihistamine. Compared with glucocorticoids, fexofenadine hydrochloride significantly suppressed the number of T cells by interfering with the development of antigen-presenting cells from the sensitization phase. Our results suggest that antihistamine has a beneficial effect on the treatment of palladium allergy compared to glucocorticoids.

  8. Characterization of the {beta}-phase of the palladium-hydrogen equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, K.J.

    1998-07-01

    The {beta}-phase of the P-C-T curves of the palladium-hydrogen system is encountered at high pressures of gaseous hydrogen and low temperatures of this system. The {beta}-phase is characterized by an increase in the concentration of hydrogen in the palladium lattice with an increase in pressure of the free hydrogen gas surrounding the palladium. The P-C-T curves in this study are determined by gravimetric measurements of the hydrided palladium sample to determine the amount of hydrogen within the palladium lattice. The amount of hydrogen is kept constant within the experimental system and the temperature is varied which changes the pressures. The objective of this experimental thesis is to accurately determine the P-C-T curves of palladium in the {beta}-phase region to pressures of 20,000 psia and medium to low temperature region of {minus}60 C to 100 C.

  9. p53 protein aggregation promotes platinum resistance in ovarian cancer.

    Science.gov (United States)

    Yang-Hartwich, Y; Soteras, M G; Lin, Z P; Holmberg, J; Sumi, N; Craveiro, V; Liang, M; Romanoff, E; Bingham, J; Garofalo, F; Alvero, A; Mor, G

    2015-07-01

    High-grade serous ovarian carcinoma (HGSOC), the most lethal gynecological cancer, often leads to chemoresistant diseases. The p53 protein is a key transcriptional factor regulating cellular homeostasis. A majority of HGSOCs have inactive p53 because of genetic mutations. However, genetic mutation is not the only cause of p53 inactivation. The aggregation of p53 protein has been discovered in different types of cancers and may be responsible for impairing the normal transcriptional activation and pro-apoptotic functions of p53. We demonstrated that in a unique population of HGSOC cancer cells with cancer stem cell properties, p53 protein aggregation is associated with p53 inactivation and platinum resistance. When these cancer stem cells differentiated into their chemosensitive progeny, they lost tumor-initiating capacity and p53 aggregates. In addition to the association of p53 aggregation and chemoresistance in HGSOC cells, we further demonstrated that the overexpression of a p53-positive regulator, p14ARF, inhibited MDM2-mediated p53 degradation and led to the imbalance of p53 turnover that promoted the formation of p53 aggregates. With in vitro and in vivo models, we demonstrated that the inhibition of p14ARF could suppress p53 aggregation and sensitize cancer cells to platinum treatment. Moreover, by two-dimensional gel electrophoresis and mass spectrometry we discovered that the aggregated p53 may function uniquely by interacting with proteins that are critical for cancer cell survival and tumor progression. Our findings help us understand the poor chemoresponse of a subset of HGSOC patients and suggest p53 aggregation as a new marker for chemoresistance. Our findings also suggest that inhibiting p53 aggregation can reactivate p53 pro-apoptotic function. Therefore, p53 aggregation is a potential therapeutic target for reversing chemoresistance. This is paramount for improving ovarian cancer patients' responses to chemotherapy, and thus increasing their

  10. Synthesis of Functionalized [3], [4], [5] and [6]Dendralenes through Palladium-Catalyzed Cross-Couplings of Substituted Allenoates.

    Science.gov (United States)

    Lippincott, Daniel J; Linstadt, Roscoe T H; Maser, Michael R; Lipshutz, Bruce H

    2017-01-16

    A mild method for the synthesis of highly functionalized [3]-[6]dendralenes is reported, representing a general strategy to diversely substituted higher homologues of the dendralenes. The methodology utilizes allenoates bearing various substitution patterns, along with a wide range of boron and alkenyl nucleophiles that couple under palladium catalysis leading to sp-, sp(2) -, and sp(3) -substituted arrays. Regioselective transformations of the newly formed unsymmetrical dendralene derivatives are demonstrated. The use of micellar catalysis, where water is the global reaction medium, and room temperature reaction conditions, highlights the green nature of this technology.

  11. Palladium-catalyzed cyclization/Heck- and cyclization/conjugate-addition-type sequences in the preparation of polysubstituted furans.

    Science.gov (United States)

    Aurrecoechea, José M; Durana, Aritz; Pérez, Elena

    2008-05-02

    Palladium-catalyzed heterocyclization-coupling sequences have been developed starting from buta-1,2,3-trienyl carbinols and electron-deficient alkenes. Polysubstituted furans are formed where the heterocyclic ring originates from the elements of the butatrienyl carbinol while the electron-deficient olefin is incorporated as a C-3 substituent. In most cases, the reaction proceeds via a Heck-type pathway leading to the efficient formation of 3-vinylfurans. However, couplings with methyl vinyl ketone display a divergent behavior to afford selectively either Heck- or hydroarylation-type products depending on reaction conditions.

  12. Recoverable Palladium(0) on Poly(vinylpyrrolidone) Catalyzed Ligand-free Suzuki Reaction in Water

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; LI Pin-Hua

    2006-01-01

    In the absence of any ligand, a recoverable palladium(O) on poly(vinylpyrrolidone) (PVP) catalyzed Suzuki reaction of aryl iodide and bromide with potassium aryltrifluoroborate was developed. The reaction conditions involved the use of water as the solvent, potassium carbonate as the base, and PVP supported palladium metal colloids as the catalyst. The palladium metal could be recovered and recycled for eight consecutive trials without significant loss of its activity.

  13. A Palladium-Binding Deltarhodopsin for Light-Activated Conversion of Protonic to Electronic Currents.

    Science.gov (United States)

    Soto-Rodríguez, Jessica; Hemmatian, Zahra; Josberger, Erik E; Rolandi, Marco; Baneyx, François

    2016-08-01

    Fusion of a palladium-binding peptide to an archaeal rhodopsin promotes intimate integration of the lipid-embedded membrane protein with a palladium hydride protonic contact. Devices fabricated with the palladium-binding deltarhodopsin enable light-activated conversion of protonic currents to electronic currents with on/off responses complete in seconds and a nearly tenfold increase in electrical signal relative to those made with the wild-type protein.

  14. Fundamental Laws of Structure and Form Changing of Palladium Loading with Hydrogen

    Institute of Scientific and Technical Information of China (English)

    GOLTSOVA M. V.; SPORTSMEN L. A.; ZHIROV G. I.

    2012-01-01

    There are reviewed some experimental results on metal-hydrogen and PdHx-hydrogen interaction.There is experimentally shown that penetration of hydrogen in palladium is accompanied with strong and micro structural effects,as well as grain shifts,etc.Moreover,the hydrogen saturation of palladium causes form-changing (bending) of palladium plate.These effects,undoubtedly,must be taken in account in technologies of low-temperature diffusion membrane apparatus exploitation.

  15. Bis-NHC chelate complexes of nickel(0) and platinum(0).

    Science.gov (United States)

    Brendel, Matthias; Braun, Carolin; Rominger, Frank; Hofmann, Peter

    2014-08-11

    For a long time d(10)-ML2 fragments have been known for their potential to activate unreactive bonds by oxidative addition. In the development of more active species, two approaches have proven successful: the use of strong σ-donating ligands leading to electron-rich metal centers and the employment of chelating ligands resulting in a bent coordination geometry. Combining these two strategies, we synthesized bis-NHC chelate complexes of nickel(0) and platinum(0). Bis(1,5-cyclooctadiene)nickel(0) and -platinum(0) react with bisimidazolium salts, deprotonated in situ at room temperature, to yield tetrahedral or trigonal-planar bis-NHC chelate olefin complexes. The synthesis and characterization of these complexes as well as a first example of C-C bond activation with these systems are reported. Due to the enforced cis arrangement of two NHCs, these compounds should open interesting perspectives for bond-activation chemistry and catalysis.

  16. A Mechanistic Study of Direct Activation of Allylic Alcohols in Palladium Catalyzed Amination Reactions

    Directory of Open Access Journals (Sweden)

    Yasemin Gumrukcu

    2015-03-01

    Full Text Available We here report a computational approach on the mechanism of allylicamination reactions using allyl-alcohols and amines as the substrates and phosphoramidite palladium catalyst 1a, which operates in the presence of catalytic amount of 1,3-diethylurea as a co-catalyst. DFT calculations showed a cooperative hydrogen-bonding array between the urea moiety and the hydroxyl group of the allyl alcohol, which strengthens the hydrogen bond between the O-H moiety of the coordinated allyl-alcohol and the carbonyl-moiety of the ligand. This hydrogen bond pattern facilitates the (rate-limiting C-O oxidative addition step and leads to lower energy isomers throughout the catalytic cycle, clarifying the role of the urea-moiety.

  17. Palladium-catalyzed direct arylation and cyclization of o-iodobiaryls to a library of tetraphenylenes

    Science.gov (United States)

    Zhu, Chendan; Zhao, Yue; Wang, Di; Sun, Wei-Yin; Shi, Zhuangzhi

    2016-09-01

    Aryl–aryl bond formation constitutes one of the most important subjects in organic synthesis. The recent developments in direct arylation reactions forming aryl–aryl bond have emerged as very attractive alternatives to traditional cross-coupling reactions. Here, we describe a general palladium-catalyzed direct arylation and cyclization of o-iodobiaryls to build a library of tetraphenylenes. This transformation represents one of the very few examples of C-H activation process that involves simultaneous formation of two aryl–aryl bonds. Oxygen plays a vital role by ensuring high reactivity, with air as the promoter furnished the best results. We anticipate this ligand-free and aerobic catalytic system will simplify the synthesis of tetraphenylenes as many of the reported methods involve use of preformed organometallic reagents and will lead to the discovery of highly efficient new direct arylation process.

  18. Toward Financially Viable Phytoextraction and Production of Plant-Based Palladium Catalysts.

    Science.gov (United States)

    Harumain, Zakuan A S; Parker, Helen L; Muñoz García, Andrea; Austin, Michael J; McElroy, Con Robert; Hunt, Andrew J; Clark, James H; Meech, John A; Anderson, Christopher W N; Ciacci, Luca; Graedel, T E; Bruce, Neil C; Rylott, Elizabeth L

    2017-02-27

    Although a promising technique, phytoextraction has yet to see significant commercialization. Major limitations include metal uptake rates and subsequent processing costs. However, it has been shown that liquid-culture-grown Arabidopsis can take up and store palladium as nanoparticles. The processed plant biomass has catalytic activity comparable to that of commercially available catalysts, creating a product of higher value than extracted bulk metal. We demonstrate that the minimum level of palladium in Arabidopsis dried tissues for catalytic activity comparable to commercially available 3% palladium-on-carbon catalysts was achieved from dried plant biomass containing between 12 and 18 g·kg(-1) Pd. To advance this technology, species suitable for in-the-field application: mustard, miscanthus, and 16 willow species and cultivars, were tested. These species were able to grow, and take up, palladium from both synthetic and mine-sourced tailings. Although levels of palladium accumulation in field-suitable species are below that required for commercially available 3% palladium-on-carbon catalysts, this study both sets the target, and is a step toward, the development of field-suitable species that concentrate catalytically active levels of palladium. Life cycle assessment on the phytomining approaches described here indicates that the use of plants to accumulate palladium for industrial applications has the potential to decrease the overall environmental impacts associated with extracting palladium using present-day mining processes.

  19. Color Reaction of 2-(2-Quinolylazo)-5-Dimethylaminoaniline with Palladium and Its Application

    OpenAIRE

    SI, Yunsen; Hu,Qiufen; HUANG, Zhangjie; Yang, Guangyu; Yin,Jiayuan

    2014-01-01

    A new chromogenic reagent, 2-(2-quinolylazo)-5-dimethylaminoaniline (QADMAA) was synthesized. A sensitive, selective and rapid method for the determination of palladium based on the rapid reaction of palladium(II) with QADMAA was developed. In the presence of 0.5-2.5 mol L-1 of hydrochloric acid solution and cetyl trimethylammonium bromide medium QADMAA reacts with palladium to form a violet complex with a molar ratio of 1:2 (palladium to QADMAA). The molar absorptivity of the chela...

  20. Review on palladium-containing perovskites: synthesis, physico-chemical properties and applications in catalysis.

    Science.gov (United States)

    Essoumhi, Abdellatif; El Kazzouli, Saïd; Bousmina, Mosto

    2014-02-01

    This review reports on the recent advances in the synthesis and physico-chemical properties of palladium-containing perovskites. Initially, the perovskite structure is briefly reviewed, then palladium-containing perovskites synthesis and physico-chemical properties are detailed. The applications of palladium-containing perovskites in catalysis; namely, NO reduction, methane combustion, methanol as well as ethanol oxidation, are briefly highlighted. The involvement and the important contribution of palladium-containing perovskites in cross-coupling reactions, especially Suzuki-Miyaura, Sonogashira, Ulmann and Grignard, are discussed.

  1. Development and Making of New Jewellery Palladium Based Alloys at JSC "Krastsvetmet"

    Institute of Scientific and Technical Information of China (English)

    YEFIMOV V. N.; MAMONOV S. N.; SHULGIN D. R.; YELTSIN S. I.

    2012-01-01

    Complex of research and development work aimed at implementation of jewellery palladium based alloys technology has been carried out at JSC Krastsvetmet.A range of palladium alloys jewellery fabrication has been organized.Compositions of a number of jewellery palladium alloys grade 850,900,950 and 990 have been proposed,their production and application in jewellery manufacture has been organized.To produce palladium alloys induction melting in inert atmosphere and melt pouring into a copper mould has been used.The ingots heat treatment conditions,as well as semi-finished jewelry plastic deformation parameters have been determined.

  2. Separation of Hydrogen Using an Electroless Deposited Thin-Film Palladium-Ceramic Composite Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Ilias, S.; King, F.G.; Fan, Ting-Fang; Roy, S. [North Carolina Agricultural and Technical State Univ., Greensboro, NC (United States). Dept. of Chemical Engineering

    1996-12-31

    The primary objective of this project was to prepare and characterize a hydrogen permselective palladium-ceramic composite membrane for high temperature gas separations and catalytic membrane reactors. Electroless plating method was used to deposit a thin palladium film on microporous ceramic substrate. The objective of this paper is to discuss the preparation and characterization of a thin-film palladium-ceramic composite membrane for selective separation of hydrogen at elevated temperatures and pressures. In this paper, we also present a model to describe the hydrogen transport through the palladium-ceramic composite membrane in a cocurrent flow configuration.

  3. Optical properties and surface morphology studies of palladium contacts on mercuric iodide single crystals

    Energy Technology Data Exchange (ETDEWEB)

    George, M.A.; Azoulay, M.; Burger, A.; Biao, Y.; Silberman, E. [Fisk Univ., Nashville, TN (United States). Dept. of Physics; Nason, D. [EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations

    1993-05-01

    Palladium is chemically suitable for electric contacts on mercuric iodide detectors for photon and nuclear radiation detection, so the understanding of palladium contacts is important for fundamental and practical scientific purposes. A study has been conducted on the surface morphology of evaporated contacts using Atomic Force Microscopy (AFM) and optical transmission and reflection. Evaporated palladium coatings are typically nonuniform and may deposit selectively on mercuric iodide surface defects. Reflection measurements show that coating thickness and surface treatment affect intensity, position and shape of a reflected peak characteristic of the mercuric iodide structure. Results indicate that the band gap energy in the surface of the mercuric iodide is lowered by palladium contacts.

  4. Optical properties and surface morphology studies of palladium contacts on mercuric iodide single crystals

    Science.gov (United States)

    George, M. A.; Azoulay, M.; Burger, A.; Biao, Y.; Silberman, E.; Nason, D.

    1993-04-01

    Palladium is chemically suitable for electric contacts on mercuric iodide detectors for photon and nuclear radiation detection, so the understanding of palladium contacts is important for fundamental and practical scientific purposes. A study has been conducted on the surface morphology of evaporated contacts using atomic force microscopy (AFM) and optical transmission and reflection. Evaporated palladium coatings are typically nonuniform and may deposit selectively on mercuric iodide surface defects. Reflection measurements show that coating thickness and surface treatment affect intensity, position, and shape of a reflected peak characteristic of the mercuric iodide structure. Results indicate that the band gap energy in the surface of the mercuric iodide is lowered by palladium contacts.

  5. Modelling and sensitivity analysis of urinary platinum excretion in anticancer chemotherapy for the recovery of platinum

    DEFF Research Database (Denmark)

    Folens, Karel; Mortier, Séverine Thérèse F C; Baeten, Janis

    2016-01-01

    Platinum (Pt) based antineoplastics are important in cancer therapy. To date the Pt which is urinary excreted by the patients ends up in wastewater. This is disadvantageous from both an economic as from an ecological point of view because Pt is a valuable material and the excretion products are t...

  6. Fabrication of electrodes with ultralow platinum loading by RF plasma processing of self-assembled arrays of Au@Pt nanoparticles

    Science.gov (United States)

    Banerjee, Ipshita; Kumaran, V.; Santhanam, Venugopal

    2016-07-01

    Conductive, carbon-free, electrocatalytically active, nanostructured electrodes with ultra-low platinum loading were fabricated using self-assembly of octadecanethiol-coated Au@Pt nanoparticles followed by RF plasma treatment. Bilayer arrays of Au@Pt nanoparticles with platinum loadings of 0.50, 1.04, 1.44, and 1.75 μg cm-2 (corresponding to 0.5, 1, 1.5 and 2 atomic layer coverage of platinum on nominally 5 nm gold core) were subjected to RF argon plasma treatment for various durations and their electrical conductivity, morphological evolution, and electrocatalytic activity characterized. Samples with monolayer and above platinum coverages exhibit maximum electrochemically active surface areas values of ˜100 m2/gpt and specific activities that are ˜4× to 6× of a reference platinum nanoparticle bilayer array. The underlying gold core influences the structural evolution of the samples upon RF plasma treatment and leads to the formation of highly active Pt(110) facets on the surface at an optimal plasma treatment duration, which also corresponds to the onset of a sharp decline in lateral sheet resistance. The sample having a two atom thick platinum coating has the highest total mass activity of 48 ± 3 m2/g(pt+au), corresponding to 44% Pt atom utilization, while also exhibiting enhanced CO tolerance as well as high methanol oxidation reaction and oxygen reduction reaction activity.

  7. Exhaust system having a gold-platinum group metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ragle, Christie Susan [Havana, IL; Silver, Ronald G [Peoria, IL; Zemskova, Svetlana Mikhailovna [Edelstein, IL; Eckstein, Colleen J [Metamora, IL

    2011-12-06

    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  8. Corrosion Studies of Platinum Nano-Particles for Fuel Cells

    DEFF Research Database (Denmark)

    Shim, Signe Sarah

    The main focus of the present thesis is on corrosion and prevention of corrosion of platinum particles supported on carbon. This is important for instance in connection with start up and shutdown of fuel cells. The degradation mechanism of platinum particles supported on carbon has been...

  9. Adlayers of palladium particles and their aggregates on porous polypropylene hollow fiber membranes as hydrogenization contractors/reactors

    NARCIS (Netherlands)

    Volkov, V.V.; Lebedeva, V.I.; Petrova, I.V.; Bobyl, A.V.; Konnikov, S.G.; Roldughin, V.I.; Erkel, J. van; Tereshchenko, G.F.

    2011-01-01

    Principal approaches for the preparation of catalytic membrane reactors based on polymer membranes containing palladium nanoparticles and for the description of their characteristics are presented. The method for the development of adlayers composed of palladium nanoparticles and their aggregates on

  10. Adlayers of palladium particles and their aggregates on porous polypropylene hollow fiber membranes as hydrogenization contractors/reactors

    NARCIS (Netherlands)

    Volkov, V.V.; Lebedeva, V.I.; Petrova, I.V.; Bobyl, A.V.; Konnikov, S.G.; Roldughin, V.I.; Erkel, J. van; Tereshchenko, G.F.

    2011-01-01

    Principal approaches for the preparation of catalytic membrane reactors based on polymer membranes containing palladium nanoparticles and for the description of their characteristics are presented. The method for the development of adlayers composed of palladium nanoparticles and their aggregates on

  11. Platinum contamination issues in ferroelectric memories

    Science.gov (United States)

    Boubekeur, H.; Mikolajick, T.; Pamler, W.; Hopfner, J.; Frey, L.; Ryssel, H.

    2002-09-01

    The contamination risk of processing with platinum electrodes on device performance in ferroelectric memories is assessed in this work. Details of platinum diffusion to the active regions at annealing temperatures of 800 degC are investigated by secondary ion mass spectroscopy, deep level transient spectroscopy, and Rutherford backscattering spectrometry techniques. Cross sectional transmission electron microscopy and local elemental analysis by energy dispersive x-ray spectroscopy were used to examine the precipitation of Pt in defect free silicon as an eventual cause of gate oxide degradation. The impact of platinum contamination on device performance is evaluated under the typical ferroelectric memory processing conditions. Results from leakage current and charge to breakdown measurements of intentionally contaminated diode and metal-oxide-semiconductor (MOS) structures, respectively, are presented. The results show that the degradation depends strongly on device design and configuration. A phosphorus doped polysilicon plug, which has the function of connecting the select transistor to the capacitor module, provides effective gettering regions and prevents the diffusion of Pt atoms to the active regions. Under typical processing conditions, no evident Pt precipitates were observed and up to a concentration level of 4 x1014 atoms/cm2, the leakage current of intentionally contaminated diodes does not increase, if the contamination occurs after front-end phosphorus doped poly-Si processing. Results from constant current charge to breakdown show a small number of breakdown events due to redeposition of Pt at the periphery of the MOS structure. The risk of processing with Pt electrodes in ferroelectric memories requires great care. Precautions like sealing the back surface and incorporating phosphorus doped polysilicon as the plug material are necessary to avoid the detrimental effects of Pt.

  12. Novel platinum(II) compounds with O,S bidentate ligands: synthesis, characterization, antiproliferative properties and biomolecular interactions.

    Science.gov (United States)

    Mügge, Carolin; Liu, Ruiqi; Görls, Helmar; Gabbiani, Chiara; Michelucci, Elena; Rüdiger, Nadine; Clement, Joachim H; Messori, Luigi; Weigand, Wolfgang

    2014-02-28

    Cisplatin and its analogues are first-line chemotherapeutic agents for the treatment of numerous human cancers. A major inconvenience in their clinical use is their strong tendency to link to sulfur compounds, especially in kidney, ultimately leading to severe nephrotoxicity. To overcome this drawback we prepared a variety of platinum complexes with sulfur ligands and analyzed their biological profiles. Here, a series of six platinum(II) compounds bearing a conserved O,S binding moiety have been synthesized and characterized as experimental anticancer agents. The six compounds differ in the nature of the O,S bidentate β-hydroxydithiocinnamic alkyl ester ligand where both the substituents on the aromatic ring and the length of the alkyl chain may be varied. The two remaining coordination positions at the square-planar platinum(II) center are occupied by a chloride ion and a DMSO molecule. These novel platinum compounds showed an acceptable solubility profile in mixed DMSO-buffer solutions and an appreciable stability at physiological pH as judged from analysis of their time-course UV-visible absorption spectra. Their anti-proliferative and pro-apoptotic activities were tested against the cisplatin-resistant lung cancer cell line A549. Assays revealed significant effects of the sample drugs at low concentrations (in the μmolar range); initial structure-activity-relationships are proposed. The activity of the apoptosis-promoting protein caspase 3/7 was determined; results proved that these novel platinum compounds, under the chosen experimental conditions, preferentially induce apoptosis over necrosis. Reactions with the model proteins cytochrome c, lysozyme and albumin were studied by ESI MS and ICP-OES to gain preliminary mechanistic information. The tested compounds turned out to metalate the mentioned proteins to a large extent. In view of the obtained results these novel platinum complexes qualify themselves as promising cytotoxic agents and merit, in our

  13. Under-Reported Aspects of Platinum Drug Pharmacology

    Directory of Open Access Journals (Sweden)

    Dirk Theile

    2017-02-01

    Full Text Available Platinum drugs remain the backbone of many antineoplastic regimens. Among the numerous chemical or pharmacological effects of platinum drugs, some aspects tend to be under-reported. Thus, this perspective paper intends to stress some neglected properties of platinum drugs: first, the physico-chemical characteristics (aquation reaction kinetics that determine site-specific toxicity; second, the impact on RNA molecules. Knowledge of the ‘RNA world’ has dramatically changed our understanding of cellular and molecular biology. The inherent RNA-crosslinking properties should make platinum-based drugs interact with coding and non-coding RNAs. Third, we will discuss the impact on the immune system, which is now recognized to substantially contribute to chemotherapy efficacy. Together, platinum drugs are in fact old drugs, but are worth re-focusing on. Many aspects are still mysterious but can pave the way to new drugs or an improved application of the already existing compounds.

  14. Controlled immobilization of palladium nanoparticles in two different fluorinated polymeric aggregate cores and their application in catalysis

    DEFF Research Database (Denmark)

    Kijima, Tetsushi; Javakhishvili, Irakli; Jankova Atanasova, Katja

    2012-01-01

    ,3,4,5,6-pentafluorostyrene)-containing ABA-triblock copolymeric nanocomposites-immobilized palladium nanoparticles were prepared by the use of the corresponding block copolymers under similar conditions. TEM images showed that palladium nanoparticles can be immobilized outside the fluorinated cooligomeric nanocomposite...... cores; in contrast, palladium nanoparticles can be effectively immobilized inside these fluorinated ABA-triblock copolymeric nanocomposite cores. Thus, these two different fluorinated copolymers enabled the controlled immobilization of palladium nanoparticles in the fluorinated nanocomposite cores...

  15. Hydrogen sensor based on a graphene - palladium nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Ulrich, E-mail: ulrich.lange@chemie.uni-r.d [Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg (Germany); Hirsch, Thomas [Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg (Germany); Mirsky, Vladimir M. [Department of Nanobiotechnology, Lausitz University of Applied Sciences, 01968 Senftenberg (Germany); Wolfbeis, Otto S. [Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg (Germany)

    2011-04-01

    A composite material was prepared from graphene and palladium nanoparticles (PdNP) by layer-by-layer deposition on gold electrodes. The material was characterized by absorption spectroscopy, scanning electron microscopy, Raman spectroscopy and surface plasmon resonance. Cyclic voltammetry demonstrated the presence of electrocatalytic centers in the palladium decorated graphene. This material can serve as a sensor material for hydrogen at levels from 0.5 to 1% in synthetic air. Pure graphene is poorly sensitive to hydrogen, but incorporation of PdNPs increases its sensitivity by more than an order of magnitude. The effects of hydrogen, nitrogen dioxide and humidity were studied. Sensor regeneration is accelerated in humid air. The sensitivity of the nanocomposite depends on the number of bilayers of graphene-PdNPs.

  16. Hydrogen response of porous palladium nano-films

    Science.gov (United States)

    Gupta, D.; Barman, P. B.; Hazra, S. K.

    2015-08-01

    Palladium nanoparticles were synthesized by reducing sodium tetrachloropalladate at 100°C using Ethylene Glycol as reducing agent. The nanoparticles were characterized by TEM (Transmission Electron Microscopy), and optical absorption spectroscopy. The average particle size (cleaned glass substrates. The high porosity of these films, as revealed by Atomic Force Microscopy (AFM) studies, made these films suitable for hydrogen sensor applications. The resistance of the films, measured by making silver paste contacts on the porous surface, changed upon exposure to 1000 ppm hydrogen in nitrogen. Optimum sensor response was obtained at 50°C, beyond which it deteriorated. The total response comprising of initial rise and subsequent fall in resistance, is due to the formation of Pd-hydrides (whose resistivity is higher relative to Pd), and closure of interparticle gaps due to lattice expansion of palladium, respectively. A detailed analysis of the results based on the sensing mechanism has been discussed in the paper.

  17. Recovery of palladium using chemically modified cedar wood powder.

    Science.gov (United States)

    Parajuli, Durga; Hirota, Koichi

    2009-10-15

    Japanese cedar wood powder (CWP) was chemically modified to a tertiary-amine-type adsorbent and studied for the selective recovery of Pd(II) from various industrial waters. Batch adsorption tests performed from 0.1 M to 5 M HCl and HNO3 systems reveal stable performance with better results in HNO3 medium. The maximum loading capacity for Pd(II) was studied in HCl as well as in HNO3. A continuous-flow experiment taking a real industrial solution revealed the feasibility of using modified CWP for the selective uptake and preconcentration of traces of palladium contained in acidic effluents. In addition, stable adsorption performance even on long exposure to gamma-irradiation and selective recovery of palladium from simulated high-level liquid waste (HLW) are important outcomes of the study.

  18. Study of electroplated silver-palladium biofouling inhibiting coating

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Hilbert, Lisbeth Rischel; Møller, Per

    , a new coating has been designed to form an inhibiting effect on the surface by itself. In this way, it is desired that the release of any matter will be in low concentration. This design is based on silver combined with nobler palladium, both with catalytic properties. Due to the potential difference......The undesired microbial and biofilm adhesions on the surfaces of food industrial facilities, water supply systems and etc. are so called as “biofouling”. Biofouling can cause many undesirable effects. Until now for solving biofouling, there are few non-toxic inhibiting treatments. In this study...... between silver and palladium while contacting with an electrolyte, the surface can form numerous discrete anodic and cathodic areas, so that an inhibiting reaction can be formed. In this paper, a series of electrochemical and biological tests were conducted to study the properties of these surfaces...

  19. Study of electroplated silver-palladium biofouling inhibiting coating

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Hilbert, Lisbeth Rischel; Schroll, Casper

    2008-01-01

    Biofouling can cause many undesirable effects in industrial and medical settings. In this study, a new biofouling inhibiting Ag-Pd surface was designed to form an inhibiting effect by itself. This design was based on silver combined with nobler palladium, both with catalytic properties. Owing...... to the potential difference between silver and palladium while contacting with an electrolyte, the surface can form numerous discrete anodic and cathodic areas, so that an inhibiting reaction can occur. In this paper, a series of electrochemical and biological investigations were conducted to study the properties...... and biofouling inhibiting mechanism of these surfaces. In this study, the evidence is presented that the inhibiting effect can be caused by the electrochemical interactions and/or electric field between Pd and Ag/AgCl combined with an organic environment....

  20. Palladium- (and nickel-) catalyzed vinylation of aryl halides†

    OpenAIRE

    DENMARK, SCOTT E.; Butler, Christopher R.

    2008-01-01

    Functionalized styrenes are extremely useful building blocks for organic synthesis and for functional polymers. One of the most general syntheses of styrenes involves the combination of an aryl halide with a vinyl organometallic reagent under catalysis by palladium or nickel complexes. This Feature Article provides the first comprehensive summary of the vinylation methods currently available along with a critical comparison of the efficiency, cost and scope of the methods.