Electrochemical CO2 and CO reduction on metal-functionalized porphyrin-like graphene

DEFF Research Database (Denmark)

Tripkovic, Vladimir; Vanin, Marco; Karamad, Mohammedreza

2013-01-01

Porphyrin-like metal-functionalized graphene structures have been investigated as possible catalysts for CO2 and CO reduction to methane or methanol. The late transition metals (Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os) and some p (B, Al, Ga) and s (Mg) metals comprised the center of the po......Porphyrin-like metal-functionalized graphene structures have been investigated as possible catalysts for CO2 and CO reduction to methane or methanol. The late transition metals (Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os) and some p (B, Al, Ga) and s (Mg) metals comprised the center...... instead of CO2. Volcano plots were constructed on the basis of scaling relations of reaction intermediates, and from these plots the reaction steps with the highest overpotentials were deduced. The Rh-porphyrin-like functionalized graphene was identified as the most active catalyst for producing methanol...... from CO, featuring an overpotential of 0.22 V. Additionally, we have also examined the hydrogen evolution and oxidation reaction, and in their case, too, Rh-porphyrin turned out to be the best catalyst with an overpotential of 0.15 V. © 2013 American Chemical Society....

Reduction of CO2 by nickel (II) macrocycle catalyst at HMDE

Indian Academy of Sciences (India)

Unknown

CO is the major product in the gaseous phase and. HCOOH the sole product formed in the solution phase. Keywords. Nickel (II) azamacrocycle; electrocatalytic reduction of CO2; electrochemical reduction. 1. Introduction. Electrochemical processes for the conversion of carbon dioxide (CO2) to organic substances have ...

Cocatalysts in Semiconductor-based Photocatalytic CO2 Reduction: Achievements, Challenges, and Opportunities.

Science.gov (United States)

Ran, Jingrun; Jaroniec, Mietek; Qiao, Shi-Zhang

2018-02-01

Ever-increasing fossil-fuel combustion along with massive CO 2 emissions has aroused a global energy crisis and climate change. Photocatalytic CO 2 reduction represents a promising strategy for clean, cost-effective, and environmentally friendly conversion of CO 2 into hydrocarbon fuels by utilizing solar energy. This strategy combines the reductive half-reaction of CO 2 conversion with an oxidative half reaction, e.g., H 2 O oxidation, to create a carbon-neutral cycle, presenting a viable solution to global energy and environmental problems. There are three pivotal processes in photocatalytic CO 2 conversion: (i) solar-light absorption, (ii) charge separation/migration, and (iii) catalytic CO 2 reduction and H 2 O oxidation. While significant progress is made in optimizing the first two processes, much less research is conducted toward enhancing the efficiency of the third step, which requires the presence of cocatalysts. In general, cocatalysts play four important roles: (i) boosting charge separation/transfer, (ii) improving the activity and selectivity of CO 2 reduction, (iii) enhancing the stability of photocatalysts, and (iv) suppressing side or back reactions. Herein, for the first time, all the developed CO 2 -reduction cocatalysts for semiconductor-based photocatalytic CO 2 conversion are summarized, and their functions and mechanisms are discussed. Finally, perspectives in this emerging area are provided. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polyoxometalate-Promoted Electrocatalytic CO2 Reduction at Nanostructured Silver in Dimethylformamide.

Science.gov (United States)

Guo, Si-Xuan; Li, Fengwang; Chen, Lu; MacFarlane, Douglas R; Zhang, Jie

2018-04-18

Electrochemical reduction of CO 2 is a promising method to convert CO 2 into fuels or useful chemicals, such as carbon monoxide (CO), hydrocarbons, and alcohols. In this study, nanostructured Ag was obtained by electrodeposition of Ag in the presence of a Keggin type polyoxometalate, [PMo 12 O 40 ] 3- (PMo). Metallic Ag is formed upon reduction of Ag + . Adsorption of PMo on the surface of the newly formed Ag lowers its surface energy thus stabilizes the nanostructure. The electrocatalytic performance of this Ag-PMo nanocomposite for CO 2 reduction was evaluated in a CO 2 saturated dimethylformamide medium containing 0.1 M [ n-Bu 4 N]PF 6 and 0.5% (v/v) added H 2 O. The results show that this Ag-PMo nanocomposite can catalyze the reduction of CO 2 to CO with an onset potential of -1.70 V versus Fc 0/+ , which is only 0.29 V more negative than the estimated reversible potential (-1.41 V) for this process and 0.70 V more positive than that on bulk Ag metal. High faradaic efficiencies of about 90% were obtained over a wide range of applied potentials. A Tafel slope of 60 mV dec -1 suggests that rapid formation of *CO 2 •- is followed by the rate-determining protonation step. This is consistent with the voltammetric data which suggest that the reduced PMo interacts strongly with CO 2 (and presumably CO 2 •- ) and hence promotes the formation of CO 2 •- .

Shape-Dependent Electrocatalytic Reduction of CO2 to CO on Triangular Silver Nanoplates.

Science.gov (United States)

Liu, Subiao; Tao, Hongbiao; Zeng, Li; Liu, Qi; Xu, Zhenghe; Liu, Qingxia; Luo, Jing-Li

2017-02-15

Electrochemical reduction of CO 2 (CO 2 RR) provides great potential for intermittent renewable energy storage. This study demonstrates a predominant shape-dependent electrocatalytic reduction of CO 2 to CO on triangular silver nanoplates (Tri-Ag-NPs) in 0.1 M KHCO 3 . Compared with similarly sized Ag nanoparticles (SS-Ag-NPs) and bulk Ag, Tri-Ag-NPs exhibited an enhanced current density and significantly improved Faradaic efficiency (96.8%) and energy efficiency (61.7%), together with a considerable durability (7 days). Additionally, CO starts to be observed at an ultralow overpotential of 96 mV, further confirming the superiority of Tri-Ag-NPs as a catalyst for CO 2 RR toward CO formation. Density functional theory calculations reveal that the significantly enhanced electrocatalytic activity and selectivity at lowered overpotential originate from the shape-controlled structure. This not only provides the optimum edge-to-corner ratio but also dominates at the facet of Ag(100) where it requires lower energy to initiate the rate-determining step. This study demonstrates a promising approach to tune electrocatalytic activity and selectivity of metal catalysts for CO 2 RR by creating optimal facet and edge site through shape-control synthesis.

Study of the oxide reduction and interstitial contents during sintering of different plain carbon steels by in situ mass spectrometry in nitrogen atmosphere

International Nuclear Information System (INIS)

Momeni, Mohammad; Gierl, Christian; Danninger, Herbert

2011-01-01

Highlights: → Degassing phenomenon was studied in plain steels with different iron base powders. → The integrated area below the MS m12 graph can be used as an indicator of formed CO. → The integrated area is an indicator for in situ carbon loss in the specimen. → Carbon loss and area below the m12 graph can be correlated. - Abstract: Reduction of oxides covering powder particles is an important process during sintering and a prerequisite to form sintering contacts in PM parts. In the present research, degassing and reduction phenomena during sintering of plain carbon steels prepared from different atomised and sponge iron powders were studied by mass spectrometry (MS) in the dilatometer under protective N 2 atmosphere. Interstitial constituents were measured by carbon and oxygen analysis. According to the results, the major part of CO 2 is formed during carbothermic reduction of surface oxides in the low to moderate temperature range ( 600 deg. C, the main product of carbothermic reduction is CO and not CO 2 , but the former cannot be detected by MS in N 2 atmosphere. Signals m44 (CO 2 ) and m12 (C) were however found to be reliable indicators for CO. Similar intensity of mass 12 signals for both ASC and SC up to 1000 deg. C is consistent with equal carbon loss through carbothermic reaction. The integrated areas below the MS signal graphs, and thus the areas of the different degassing peaks obtained in the MS, were used as at least semi-quantitative estimation of the amount of gases formed, bearing in mind that MS is not really a quantitative analytical tool. Although a clearly defined relationship is not visible between oxygen loss and area below the m16 graph, the area for m12 can be used as an indicator for in situ carbon loss in the specimen. Increasing integrated areas for m12 and 16 between 800 and 1300 deg. C with only marginal enhancement of m44 indicates that the major part of oxides are removed as CO, in agreement with Boudouard equilibrium, at

Enhanced selective photocatalytic CO{sub 2} reduction into CO over Ag/CdS nanocomposites under visible light

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zezhou; Qin, Jiani; Jiang, Min; Ding, Zhengxin; Hou, Yidong, E-mail: ydhou@fzu.edu.cn

2017-01-01

Highlights: • Ag/CdS nanocomposites were prepared by a facile photodeposition method. • Ag/CdS was more effective as a photocatalyst for CO{sub 2} reduction than CdS. • Ag as cocatalyst served as electron trap as well as active site for CO{sub 2} reduction reaction. - Abstract: Photocatalytic reduction of carbon dioxide can convert chemically inert carbon dioxide into useful chemical fuel in a mild manner. Herein, Ag-CdS nanocomposites were prepared by photodeposition method and examined for photocatalytic CO{sub 2} reduction under visible light. Meanwhile, the nanocomposites were characterized by XRD, SEM, TEM, XPS, DRS and PL in detail. The results show that, the deposition of Ag improves the photocatalytic performance of CdS, especially in the selectivity of CO{sub 2}-to-CO. The highest photocatalytic activity is achieved over 1.0 wt.% Ag/CdS, with an increase by 3 times in comparison to CdS. In this reaction system, Ag can serve as electron trap as well as active site for CO{sub 2} reduction, which is probably responsible for the enhanced activity and selectivity of CO{sub 2} to CO over Ag/CdS. The possible mechanism of CO{sub 2} photoreduction over Ag/CdS was proposed in view of the abovementioned analysis.

Net ecosystem exchange of CO2 and H2O fluxes from irrigated grain sorghum and maize in the Texas High Plains

Science.gov (United States)

Net ecosystem exchange (NEE) of carbon dioxide (CO2) and water vapor (H2O) fluxes from irrigated grain sorghum (Sorghum bicolor L. Moench) and maize (Zea mays L.) fields in the Texas High Plains were quantified using the eddy covariance (EC) technique during 2014-2016 growing seasons and examined in...

Surface modification and enhanced photocatalytic CO{sub 2} reduction performance of TiO{sub 2}: a review

Energy Technology Data Exchange (ETDEWEB)

Low, Jingxiang; Cheng, Bei [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Yu, Jiaguo, E-mail: jiaguoyu@yahoo.com [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2017-01-15

Highlights: • Application of modified TiO{sub 2} for photocatalytic CO{sub 2} reduction is summarized. • Different surface modification strategies of TiO{sub 2} are highlighted. • Summary and future perspectives in photocatalytic CO{sub 2} reduction are presented. - Abstract: Recently, the excessive consumption of fossil fuels has caused high emissions of the greenhouse gases, CO{sub 2} into atmosphere and global energy crisis. Mimicking the natural photosynthesis by using semiconductor materials to achieve photocatalytic CO{sub 2} reduction into valuable solar fuels such as CH{sub 4}, HCO{sub 2}H, CH{sub 2}O, and CH{sub 3}OH is known as one of the best solutions for addressing the aforementioned issue. Among various proposed photocatalysts, TiO{sub 2} has been extensively studied over the past several decades for photocatalytic CO{sub 2} reduction because of its cheapness and environmental friendliness. Particularly, surface modification of TiO{sub 2} has attracted numerous interests due to its capability of enhancing the light absorption ability, facilitating the electron-hole separation, tuning the CO{sub 2} reduction selectivity and increasing the CO{sub 2} adsorption and activation ability of TiO{sub 2} for photocatalytic CO{sub 2} reduction. In this review, recent approaches of the surface modification of TiO{sub 2} for photocatalytic CO{sub 2} reduction, including impurity doping, metal deposition, alkali modification, heterojunction construction and carbon-based material loading, are presented. The photocatalytic CO{sub 2} reduction mechanism and pathways of TiO{sub 2} are discussed. The future research direction and perspective of photocatalytic CO{sub 2} reduction over surface-modified TiO{sub 2} are also presented.

CO2 reduction through energy conservation

International Nuclear Information System (INIS)

1991-05-01

A study was carried out of the potential to economically reduce carbon dioxide emissions through energy conservation in the petroleum and natural gas industry. The study examined current and projected emissions levels, cogeneration at gas plants, flaring, economics, regulation, reporting requirements, implementation, and research and development. Economically attractive energy conservation measures can reduce oil and gas industry, exclusive of Athabasca oil sands operations, CO 2 emissions by 6-7%. The energy conservation options identified range from field energy awareness committees through to equipment retrofits and replacement. At ca 3 million tonnes/y, these reductions will not offset the increases in oil and gas related CO 2 emissions anticipated by producers and Alberta government agencies. There will be increasing emphasis on in-situ bitumen production, more energy intensive light crude oil production and increasing natural gas sales, increasing energy inputs in excess of reductions. Cogeneration of electricity for utility company distribution and for internally required steam at gas plants and in-situ production sites is not economic due to low electricity prices. 8 tabs

CO2 reduction by dematerialization

Energy Technology Data Exchange (ETDEWEB)

Hekkert, M.P. [Department of Innovation Studies, Copernicus Institute, Utrecht University, Utrecht (Netherlands)

2002-04-01

Current policy for the reduction of greenhouse gases is mainly concerned with a number of types of solutions: energy saving, shifting to the use of low-carbon fuels and the implementation of sustainable energy technologies. Recent research has shown that a strategy directed at a more efficient use of materials could make a considerable contribution to reducing CO2 emissions. Moreover, the costs to society as a whole of such a measure appear to be very low.

Effect of copper oxide electrocatalyst on CO2 reduction using Co3O4 as anode

Directory of Open Access Journals (Sweden)

V.S.K. Yadav

2016-09-01

Full Text Available The reduction of carbon dioxide (CO2 to products electrochemically (RCPE in 0.5 M NaHCO3 and Na2CO3 liquid phase electrolyte solutions was investigated. Cobalt oxide (Co3O4 as anode and cuprous oxide (Cu2O as the cathode were considered, respectively. The impacts of applied potential with time of reaction during reduction of CO2 to products were studied. The anode and cathode were prepared by depositing electrocatalysts on the graphite plate. Ultra-fast liquid chromatography (UFLC was used to analyze the products obtained from the reduction of CO2. The feasible way of reduction by applying voltages with current densities was clearly correlated. The results illustrate the capability of electrocatalyst successfully to remove atmospheric CO2 in the form of valuable chemicals. Maximum Faradaic efficiency of ethanol was 98.1% at 2 V and for formic acid (36.6% at 1.5 V was observed in NaHCO3. On the other hand, in Na2CO3 electrolyte solution maximum efficiency for ethanol was 55.21% at 1.5 V and 25.1% for formic acid at 2 V. In both electrolytes other end products like methanol, propanol, formaldehyde and acetic acid were formed at various applied voltage and output current densities.

Reduction of CO{sub 2} emission and oil dependency with biomass-based polygeneration

Energy Technology Data Exchange (ETDEWEB)

Joelsson, Jonas M; Gustavsson, Leif [Ecotechnology and Environmental Science, Department of Engineering and Sustainable Development, Mid Sweden University, SE-831 25 Oestersund (Sweden)

2010-07-15

We compare different options for the use of lignocellulosic biomass to reduce CO{sub 2} emission and oil use, focusing on polygeneration of biomass-based motor fuels and electricity, and discuss methodological issues related to such comparisons. The use of biomass can significantly reduce CO{sub 2} emission and oil use, but there is a trade-off between the reductions in CO{sub 2} emission and oil use. Bioelectricity from stand-alone plants replacing coal-based electricity reduced CO{sub 2} emission by 99 kg per GJ biomass input but gave no oil use reduction. Stand-alone produced methanol replacing diesel reduced the CO{sub 2} emission with 38 kg and the oil use with 0.67 GJ per GJ biomass, indicating that a potential CO{sub 2} emission reduction of 90 kg is lost per GJ oil reduced. CO{sub 2} emission and oil use reduction for alternatives co-producing fuel and electricity fall between the stand-alone alternatives. Plug-in hybrid-electric vehicles using bioelectricity reduced CO{sub 2} emission by 75-88 kg and oil use by 0.99-1.2 GJ, per GJ biomass input. Biomass can also reduce CO{sub 2} emission and/or oil use more efficiently if fossil-fuel-fired boilers or electric heating is replaced by district heating from biomass-based combined heat and power generation. This is also true if electricity or motor fuel is produced from black liquor gasification in pulp mills or if wood is used instead of concrete in building construction. Biomass gasification is an important technology to achieve large reductions, irrespective of whether CO{sub 2} emission or oil use reduction is prioritised. (author)

The improvement of CO2 emission reduction policies based on system dynamics method in traditional industrial region with large CO2 emission

International Nuclear Information System (INIS)

Li, Fujia; Dong, Suocheng; Li, Zehong; Li, Yu; Li, Shantong; Wan, Yongkun

2012-01-01

Some traditional industrial regions are characterized by high industrial proportion and large CO 2 emission. They are facing dual pressures of maintaining economic growth and largely reducing CO 2 emission. From the perspective of study of typological region, taking the typical traditional industrial region—Liaoning Province of China as a case, this study establishes a system dynamics model named EECP and dynamically simulates CO 2 emission trends under different conditions. Simulation results indicate, compared to the condition without CO 2 emission reduction policies, CO 2 emission intensity under the condition of implementing CO 2 emission reduction policies of “Twelfth Five-Year Plan” is decreased by 11% from 2009 to 2030, but the economic cost is high, making the policies implementation faces resistance. Then some improved policies are offered and proved by EECP model that they can reduce CO 2 emission intensity after 2021 and decrease the negative influence to GDP, realizing the improvement objects of reducing CO 2 emission and simultaneously keeping a higher economy growth speed. The improved policies can provide reference for making and improving CO 2 emission reduction policies in other traditional industrial regions with large CO 2 emission. Simultaneously, EECP model can provide decision-makers with reference and help for similar study of energy policy. - Highlights: ► We build EECP model for CO 2 emission reduction study in traditional industry region. ► By the model, we simulate CO 2 emission trend and improve emission reduction policy. ► By improvement, both CO 2 emission intensity and economic cost can be largely reduced. ► Besides CO 2 emission is reduced effectively, higher GDP increment speed is kept. ► EECP model can be widely used for making and improving regional energy policies.

Mesostructure-Induced Selectivity in CO2 Reduction Catalysis.

Science.gov (United States)

Hall, Anthony Shoji; Yoon, Youngmin; Wuttig, Anna; Surendranath, Yogesh

2015-12-02

Gold inverse opal (Au-IO) thin films are active for CO2 reduction to CO with high efficiency at modest overpotentials and high selectivity relative to hydrogen evolution. The specific activity for hydrogen evolution diminishes by 10-fold with increasing porous film thickness, while CO evolution activity is largely unchanged. We demonstrate that the origin of hydrogen suppression in Au-IO films stems from the generation of diffusional gradients within the pores of the mesostructured electrode rather than changes in surface faceting or Au grain size. For electrodes with optimal mesoporosity, 99% selectivity for CO evolution can be obtained at overpotentials as low as 0.4 V. These results establish electrode mesostructuring as a complementary method for tuning selectivity in CO2-to-fuels catalysis.

A multinational model for CO2 reduction: defining boundaries of future CO2 emissions in nine countries

International Nuclear Information System (INIS)

Kram, Tom; Hill, Douglas.

1996-01-01

A need to make substantial future reductions in greenhouse gas emissions would require major changes in national energy systems. Nine industrialized countries have explored the technical boundaries of CO 2 emission restrictions during the next 40 to 50 years using comparable scenario assumptions and a standard model, MARKAL. Quantitative results for the countries are shown side by side in a set of energy maps that compare the least-cost evolution of the national energy systems by the main factors that contribute to CO 2 emissions. The ability to restrict future CO 2 emissions and the most cost-effective measures for doing so differ among the countries; an international agreement that would mandate substantial emission restrictions among countries by an equal percentage reduction is clearly impossible. The results are a first step toward a basis for allocating such international reductions, and the multinational process by which they were produced provides an example for further international greenhouse gas abatement costing studies. (Author)

Reaction mechanisms of CO2 activation and catalytic reduction

International Nuclear Information System (INIS)

Wolff, Niklas von

2016-01-01

The use of CO 2 as a C1 chemical feedstock for the fine chemical industry is interesting both economically and ecologically, as CO 2 is non-toxic, abundant and cheap. Nevertheless, transformations of CO 2 into value-added products is hampered by its high thermodynamic stability and its inertness toward reduction. In order to design new catalysts able to overcome this kinetic challenge, a profound understanding of the reaction mechanisms at play in CO 2 reduction is needed. Using novel N/Si+ frustrated Lewis pairs (FLPs), the influence of CO 2 adducts and different hydro-borane reducing agents on the reaction mechanism in the catalytic hydroboration of CO 2 were investigated, both by DFT calculations and experiments. In a second step, the reaction mechanism of a novel reaction for the creation of C-C bonds from CO 2 and pyridyl-silanes (C 5 H 4 N-SiMe 3 ) was analyzed by DFT calculations. It was shown that CO 2 plays a double role in this transformation, acting both as a catalyst and a C1-building block. The fine understanding of this transformation then led to the development of a novel approach for the synthesis of sulfones and sulfonamides. Starting from SO 2 and aromatic silanes/amine silanes, these products were obtained in a single step under metal-free conditions. Noteworthy, sulfones and sulfonamides are common motifs in organic chemistry and found in a variety of highly important drugs. Finally, this concept was extended to aromatic halides as coupling partners, and it was thus shown for the first time that a sulfonylative Hiyama reaction is a possible approach to the synthesis of sulfones. (author) [fr

Analysis of CO2 emissions reduction in the Malaysian transportation sector: An optimisation approach

International Nuclear Information System (INIS)

Mustapa, Siti Indati; Bekhet, Hussain Ali

2016-01-01

The demand for transport services is expected to rise, causing the CO 2 emissions level to increase as well. In Malaysia, the transportation sector accounts for 28% of total CO 2 emissions, of which 85% comes from road transport. By 2020, Malaysia is targeting a reduction in CO 2 emissions intensity by up to 40% and in this effort the role of road transport is paramount. This paper attempts to investigate effective policy options that can assist Malaysia in reducing the CO 2 emissions level. An Optimisation model is developed to estimate the potential CO 2 emissions mitigation strategies for road transport by minimising the CO 2 emissions under the constraint of fuel cost and demand travel. Several mitigation strategies have been applied to analyse the effect of CO 2 emissions reduction potential. The results demonstrate that removal of fuel price subsidies can result in reductions of up to 652 ktonnes of fuel consumption and CO 2 emissions can be decreased by 6.55%, which would enable Malaysia to hit its target by 2020. CO 2 emissions can be reduced significantly, up to 20%, by employing a combination of mitigation policies in Malaysia. This suggests that appropriate mitigation policies can assist the country in its quest to achieve the CO 2 emissions reduction target. - Highlights: • An optimisation model for CO 2 emissions reduction in Malaysia's road transport is formulated. • Sensible policy options to achieve the CO 2 emissions reduction target are provided. • Increase in fuel price has induced shift towards fuel efficient vehicles. • The CO 2 emissions can be reduced up to 5.7 MtCO 2 with combination of mitigation policies.

The role of CO* as a spectator in CO₂ electro-reduction on RuO₂

DEFF Research Database (Denmark)

Bhowmik, Arghya; Hansen, Heine Anton; Vegge, Tejs

2017-01-01

evolution reaction (HER). We show that a moderate CO* coverage (∼50%) is necessary for obtaining methanol as a product and that higher CO* coverages leads to very low overpotential for formic acid evolution. Our analysis also clarifies the importance of the reaction condition for CO2 reduction to liquid......RuO2-based electrocatalysts are found to be active at low overpotential toward direct electrochemical reduction of CO2 to formic acid and methanol. RuO2 can circumvent the thermodynamic bottleneck resulting from the scaling relations observed on metallic electrocatalyst, by utilizing an alternate...

Burrows of the Semi-Terrestrial Crab Ucides cordatus Enhance CO2 Release in a North Brazilian Mangrove Forest

Science.gov (United States)

Pülmanns, Nathalie; Diele, Karen; Mehlig, Ulf; Nordhaus, Inga

2014-01-01

Ucides cordatus is an abundant mangrove crab in Brazil constructing burrows of up to 2 m depth. Sediment around burrows may oxidize during low tides. This increase in sediment-air contact area may enhance carbon degradation processes. We hypothesized that 1) the sediment CO2 efflux rate is greater with burrows than without and 2) the reduction potential in radial profiles in the sediment surrounding the burrows decreases gradually, until approximating non-bioturbated conditions. Sampling was conducted during the North Brazilian wet season at neap tides. CO2 efflux rates of inhabited burrows and plain sediment were measured with a CO2/H2O gas analyzer connected to a respiration chamber. Sediment redox potential, pH and temperature were measured in the sediment surrounding the burrows at horizontal distances of 2, 5, 8 and 15 cm at four sediment depths (1, 10, 30 and 50 cm) and rH values were calculated. Sediment cores (50 cm length) were taken to measure the same parameters for plain sediment. CO2 efflux rates of plain sediment and individual crab burrows with entrance diameters of 7 cm were 0.7–1.3 µmol m−2 s−1 and 0.2–0.4 µmol burrows−1 s−1, respectively. CO2 released from a Rhizophora mangle dominated forest with an average of 1.7 U. cordatus burrows−1 m−2 yielded 1.0–1.7 µmol m−2 s−1, depending on the month and burrow entrance diameter. Laboratory experiments revealed that 20–60% of the CO2 released by burrows originated from crab respiration. Temporal changes in the reduction potential in the sediment surrounding the burrows did not influence the CO2 release from burrows. More oxidized conditions of plain sediment over time may explain the increase in CO2 release until the end of the wet season. CO2 released by U. cordatus and their burrows may be a significant pathway of CO2 export from mangrove sediments and should be considered in mangrove carbon budget estimates. PMID:25313661

Burrows of the semi-terrestrial crab Ucides cordatus enhance CO2 release in a North Brazilian mangrove forest.

Directory of Open Access Journals (Sweden)

Nathalie Pülmanns

Full Text Available Ucides cordatus is an abundant mangrove crab in Brazil constructing burrows of up to 2 m depth. Sediment around burrows may oxidize during low tides. This increase in sediment-air contact area may enhance carbon degradation processes. We hypothesized that 1 the sediment CO2 efflux rate is greater with burrows than without and 2 the reduction potential in radial profiles in the sediment surrounding the burrows decreases gradually, until approximating non-bioturbated conditions. Sampling was conducted during the North Brazilian wet season at neap tides. CO2 efflux rates of inhabited burrows and plain sediment were measured with a CO2/H2O gas analyzer connected to a respiration chamber. Sediment redox potential, pH and temperature were measured in the sediment surrounding the burrows at horizontal distances of 2, 5, 8 and 15 cm at four sediment depths (1, 10, 30 and 50 cm and rH values were calculated. Sediment cores (50 cm length were taken to measure the same parameters for plain sediment. CO2 efflux rates of plain sediment and individual crab burrows with entrance diameters of 7 cm were 0.7-1.3 µmol m(-2 s(-1 and 0.2-0.4 µmol burrows(-1 s(-1, respectively. CO2 released from a Rhizophora mangle dominated forest with an average of 1.7 U. cordatus burrows(-1 m(-2 yielded 1.0-1.7 µmol m(-2 s(-1, depending on the month and burrow entrance diameter. Laboratory experiments revealed that 20-60% of the CO2 released by burrows originated from crab respiration. Temporal changes in the reduction potential in the sediment surrounding the burrows did not influence the CO2 release from burrows. More oxidized conditions of plain sediment over time may explain the increase in CO2 release until the end of the wet season. CO2 released by U. cordatus and their burrows may be a significant pathway of CO2 export from mangrove sediments and should be considered in mangrove carbon budget estimates.

Burrows of the semi-terrestrial crab Ucides cordatus enhance CO2 release in a North Brazilian mangrove forest.

Science.gov (United States)

Pülmanns, Nathalie; Diele, Karen; Mehlig, Ulf; Nordhaus, Inga

2014-01-01

Ucides cordatus is an abundant mangrove crab in Brazil constructing burrows of up to 2 m depth. Sediment around burrows may oxidize during low tides. This increase in sediment-air contact area may enhance carbon degradation processes. We hypothesized that 1) the sediment CO2 efflux rate is greater with burrows than without and 2) the reduction potential in radial profiles in the sediment surrounding the burrows decreases gradually, until approximating non-bioturbated conditions. Sampling was conducted during the North Brazilian wet season at neap tides. CO2 efflux rates of inhabited burrows and plain sediment were measured with a CO2/H2O gas analyzer connected to a respiration chamber. Sediment redox potential, pH and temperature were measured in the sediment surrounding the burrows at horizontal distances of 2, 5, 8 and 15 cm at four sediment depths (1, 10, 30 and 50 cm) and rH values were calculated. Sediment cores (50 cm length) were taken to measure the same parameters for plain sediment. CO2 efflux rates of plain sediment and individual crab burrows with entrance diameters of 7 cm were 0.7-1.3 µmol m(-2) s(-1) and 0.2-0.4 µmol burrows(-1) s(-1), respectively. CO2 released from a Rhizophora mangle dominated forest with an average of 1.7 U. cordatus burrows(-1) m(-2) yielded 1.0-1.7 µmol m(-2) s(-1), depending on the month and burrow entrance diameter. Laboratory experiments revealed that 20-60% of the CO2 released by burrows originated from crab respiration. Temporal changes in the reduction potential in the sediment surrounding the burrows did not influence the CO2 release from burrows. More oxidized conditions of plain sediment over time may explain the increase in CO2 release until the end of the wet season. CO2 released by U. cordatus and their burrows may be a significant pathway of CO2 export from mangrove sediments and should be considered in mangrove carbon budget estimates.

Achieving CO2 Emissions Reduction Goals with Energy Infrastructure Projects

International Nuclear Information System (INIS)

Eberlinc, M.; Medved, K.; Simic, J.

2013-01-01

The EU has set its short-term goals in the Europe 2020 Strategy (20% of CO 2 emissions reduction, 20% increase in energy efficiency, 20% share of renewables in final energy). The analyses show that the EU Member States in general are on the right track of achieving these goals; they are even ahead (including Slovenia). But setting long-term goals by 2050 is a tougher challenge. Achieving CO 2 emissions reduction goes hand in hand with increasing the share of renewables and strategically planning the projects, which include exploiting the potential of renewable sources of energy (e.g. hydropower). In Slovenia, the expected share of hydropower in electricity production from large HPPs in the share of renewables by 2030 is 1/3. The paper includes a presentation of a hydro power plants project on the middle Sava river in Slovenia and its specifics (influenced by the expansion of the Natura 2000 protected sites and on the other hand by the changes in the Environment Protection Law, which implements the EU Industrial Emissions Directive and the ETS Directive). Studies show the importance of the HPPs in terms of CO 2 emissions reduction. The main conclusion of the paper shows the importance of energy infrastructure projects, which contribute to on the one hand the CO 2 emissions reduction and on the other the increase of renewables.(author)

Electrochemical CO2 Reduction by Ni-containing Iron Sulfides: How Is CO2 Electrochemically Reduced at Bisulfide-Bearing Deep-sea Hydrothermal Precipitates?

International Nuclear Information System (INIS)

Yamaguchi, Akira; Yamamoto, Masahiro; Takai, Ken; Ishii, Takumi; Hashimoto, Kazuhito; Nakamura, Ryuhei

2014-01-01

The discovery of deep-sea hydrothermal vents on the late 1970's has led to many hypotheses concerning chemical evolution in the prebiotic ocean and the early evolution of energy metabolism in ancient Earth. Such studies stand on the quest for the bioenergetic evolution to utilize reducing chemicals such as H 2 for CO 2 reduction and carbon assimilation. In addition to the direct reaction of H 2 and CO 2 , the electrical current passing across a bisulfide-bearing chimney structure has pointed to the possible electrocatalytic CO 2 reduction at the cold ocean-vent interface (R. Nakamura, et al. Angew. Chem. Int. Ed. 2010, 49, 7692 − 7694). To confirm the validity of this hypothesis, here, we examined the energetics of electrocatalytic CO 2 reduction by iron sulfide (FeS) deposits at slightly acidic pH. Although FeS deposits inefficiently reduced CO 2 , the efficiency of the reaction was substantially improved by the substitution of Fe with Ni to form FeNi 2 S 4 (violarite), of which surface was further modified with amine compounds. The potential-dependent activity of CO 2 reduction demonstrated that CO 2 reduction by H 2 in hydrothermal fluids was involved in a strong endergonic electron transfer reaction, suggesting that a naturally occurring proton-motive force (PMF) as high as 200 mV would be established across the hydrothermal vent chimney wall. However, in the chimney structures, H 2 generation competes with CO 2 reduction for electrical current, resulting in rapid consumption of the PMF. Therefore, to maintain the PMF and the electrosynthesis of organic compounds in hydrothermal vent mineral deposits, we propose a homeostatic pH regulation mechanism of FeS deposits, in which elemental hydrogen stored in the hydrothermal mineral deposits is used to balance the consumption of the electrochemical gradient by H 2 generation

CO2 reduction strategies for the Czech Republic

International Nuclear Information System (INIS)

De Kruijk, H.; Van den Broek, M.A.; Van Harmelen, T.; Van Oostvoorn, F.; Maly, M.

1994-08-01

Reduction of CO 2 emissions now has high priority on the international political agenda. The UN Convention on Climate Change provides countries the option for fulfilling the CO 2 reduction obligations individually or jointly. But before identifying opportunities, a reference path or scenario is needed to indicate how emissions will vary without joint implementation of projects or policies. This paper looks at the situation in the Czech Republic. First objective of the study concerns collecting information on CO 2 emissions in the Czech Republic, a reference scenario for CO 2 developments, and the reduction scope till the year 2015. Second objective is development of CEC energy/environmental model EFOM-ENV (Energy Flow and Optimization Model - ENVironment) for the Czech Republic. In the new orientation towards a market economy it is important to start preparing policy recommendations for energy and environmental needs based on the least cost approach. Presently the energy/environmental model EFOM-ENV is used for this type of studies by CEC, Directorate-General 12, and research institutes in almost all EC countries. It showed usefulness in EC countries for developing integrated energy /environmental strategies. Furthermore, based on its experience with this type of studies, the Netherlands Energy Research Foundation has the last years developed a GAMS PC-version of EFOM-ENV, very flexible and efficient to use. Increasing international cooperation in areas of energy and environmental policies requires a common analytical approach. Particularly for preparing harmonized emission control policies in Europe the use of the EC model EFOM-ENV for all Central European countries can provide comparable and useful insight in the relation between energy use and emissions in Central Europe. In fact similar studies have been and will be conducted for the Slovak Republic, Hungary, Bulgaria, other Central European countries. 4 figs., 5 tabs., 6 refs

Reduction of CO2 emissions by influencing fuel prices

International Nuclear Information System (INIS)

Keller, M.; Zbinden, R.; Haan, P.; Gruetter, J.; Ott, W.

2002-01-01

The CO 2 law stipulates quantitative targets for CO 2 emissions (reductions of 10% by 2010 compared with 1990, 15% for heating fuels, 8% for motor fuels). For motor fuels, it is currently estimated that the target will be missed by about 15%, or 2 to 2.5 million tonnes of CO 2 . In order to reach the targets, therefore, all measures that can be taken to reduce emissions are to be checked out and, where sensible and possible, implemented too. The subject of this study is the preferential treatment of diesel, natural gas, liquefied gas and bio-fuels as far as taxation is concerned, with compensation of tax losses on the petrol side. Also, the possibilities for promoting energy-efficient cars are looked at. The reduction of the price for diesel (at least 25 Swiss cents when compensated for via the petrol price) is considered to be unsuitable for reaching the targets because, in the final analysis, fuel sales - the determining factor for the CO 2 emissions that are charged to Switzerland - will increase instead of decreasing. Also, reservations are expressed from the environmental point of view (increased NO x emissions and, in particular, emissions of particulate matter). The modified measure proposed (fixed difference between the prices for petrol and diesel of 25 Swiss cents, for example) is looked at less critically, because it does actually lead to a reduction of CO 2 , even if only a modest one (approx. 10% of the gap to be bridged). On the environmental side, the same reservations apply. Bonus-malus systems, on the other hand, permit a selective choice of the objects of promotion (efficient and, possibly, low-emission vehicles), avoid the unjust preferential treatment of goods traffic and can be implemented without disturbing international price structures (fuel tourism). A bonus-malus system applied at purchase (e.g. different levels of car taxation) is considered to be more efficient than a differentiation in vehicle (road) tax. The promotion of gas is a

Opportunities and challenges in the electrocatalysis of CO2 and CO reduction using bifunctional surfaces

DEFF Research Database (Denmark)

Jovanov, Zarko; Hansen, Heine A.; Varela Gasque, Ana Sofia

2016-01-01

Electrolysis could enable the large-scale conversion of CO2 to fuels and small molecules. This perspective discusses the state-of-the-art understanding of CO2 and CO reduction electrocatalysis and provides an overview of the most promising approaches undertaken thus far. We set to explore "bifunc...

Economic efficiency of CO2 reduction programs

International Nuclear Information System (INIS)

Tahvonen, O.; Storch, H. von; Storch, J. von

1993-01-01

A highly simplified time-dependent low-dimensional system has been designed to describe conceptually the interaction of climate and economy. Enhanced emission of carbon dioxide (CO 2 ) is understood as the agent that not only favors instantaneous consumption but also causes unfavorable climate changes at a later time. The problem of balancing these two counterproductive effects of CO 2 emissions on a finite time horizon is considered. The climate system is represented by just two parameters, namely a globally averaged near-surface air-temperature and a globally averaged troposheric CO 2 concentration. The costs of abating CO 2 emissions are monitored by a function which depends quadratically on the percentage reduction of emission compared to an 'uncontrolled emission' scenario. Parameters are fitted to historical climate data and to estimates from studies of CO 2 abatement costs. Two optimization approaches, which differ from earlier attempts to describe the interaction of economy and climate, are discussed. In the 'cost oriented' strategy an optimal emission path is identified which balances the abatement costs and explicitly formulated damage costs. These damage costs, whose estimates are very uncertain, are hypothesized to be a linear function of the time-derivative of temperature. In the 'target oriented' strategy an emission path is chosen so that the abatement costs are minimal while certain restrictions on the terminal temperature and concentration change are met. (orig.)

CO2 Reduction Catalyzed by Nitrogenase: Pathways to Formate, Carbon Monoxide, and Methane.

Science.gov (United States)

Khadka, Nimesh; Dean, Dennis R; Smith, Dayle; Hoffman, Brian M; Raugei, Simone; Seefeldt, Lance C

2016-09-06

The reduction of N2 to NH3 by Mo-dependent nitrogenase at its active-site metal cluster FeMo-cofactor utilizes reductive elimination of Fe-bound hydrides with obligatory loss of H2 to activate the enzyme for binding/reduction of N2. Earlier work showed that wild-type nitrogenase and a nitrogenase with amino acid substitutions in the MoFe protein near FeMo-cofactor can catalytically reduce CO2 by two or eight electrons/protons to carbon monoxide (CO) and methane (CH4) at low rates. Here, it is demonstrated that nitrogenase preferentially reduces CO2 by two electrons/protons to formate (HCOO(-)) at rates >10 times higher than rates of CO2 reduction to CO and CH4. Quantum mechanical calculations on the doubly reduced FeMo-cofactor with a Fe-bound hydride and S-bound proton (E2(2H) state) favor a direct reaction of CO2 with the hydride ("direct hydride transfer" reaction pathway), with facile hydride transfer to CO2 yielding formate. In contrast, a significant barrier is observed for reaction of Fe-bound CO2 with the hydride ("associative" reaction pathway), which leads to CO and CH4. Remarkably, in the direct hydride transfer pathway, the Fe-H behaves as a hydridic hydrogen, whereas in the associative pathway it acts as a protic hydrogen. MoFe proteins with amino acid substitutions near FeMo-cofactor (α-70(Val→Ala), α-195(His→Gln)) are found to significantly alter the distribution of products between formate and CO/CH4.

High-throughput synthesis of mixed-metal electrocatalysts for CO2 reduction

International Nuclear Information System (INIS)

He, Jingfu; Dettelbach, Kevan E.; Li, Tengfei; Salvatore, Danielle A.; Berlinguette, Curtis P.

2017-01-01

The utilization of CO 2 as a feedstock requires fundamental breakthroughs in catalyst design. The efficiencies and activities of pure metal electrodes towards the CO 2 reduction reaction are established, but the corresponding data on mixed-metal systems are not as well developed. In this study we show that the near-infrared driven decomposition (NIRDD) of solution-deposited films of metal salts and subsequent electrochemical reduction offers the unique opportunity to form an array of mixed-metal electrocatalyst coatings with excellent control of the metal stoichiometries. This synthetic method enabled us to develop an empirical structure-property correlation to help inform the development of optimized CO 2 catalyst compositions. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Incentives for subcontractors to adopt CO2 emission reporting and reduction techniques

International Nuclear Information System (INIS)

Scholtens, Bert; Kleinsmann, Renske

2011-01-01

We investigate the incentives for subcontractors (couriers) of a transport and logistics company to report about their CO 2 emissions and to implement CO 2 reducing technologies. Furthermore, we try to find out whether these incentives differ between British and Dutch couriers. We find that several incentives play a significant role. Subcontractors in the Netherlands predominantly are extrinsically motivated to engage in CO 2 reporting and reduction techniques. This is because they are mainly driven by regulatory compliance, energy costs and implementation costs. In contrast, British subcontractors are much more intrinsically motivated to comply. They are predominantly driven by energy costs, environmental awareness, relationship building and reputation building. The contractor will have to account for these differences in making its policies work. - Research highlights: → We investigate incentives for couriers to report CO 2 emissions and to implement CO 2 reduction techniques. → We compare couriers in the Netherlands and the United Kingdom. → Several incentives are significant for the adoption of CO 2 reporting and reduction measures. → There are significant differences in the sensitivity for incentives in the Netherlands and the UK.

Topotactic reduction of YBaCo2O5 and LaBaCo2O5: square-planar Co(I) in an extended oxide.

Science.gov (United States)

Seddon, James; Suard, Emmanuelle; Hayward, Michael A

2010-03-03

The low-temperature reduction of YBaCo(2)O(5) and LaBaCo(2)O(5) with NaH to form YBaCo(2)O(4.5) and YBaCo(2)O(4.25), respectively, demonstrates that the structures of anion-deficient materials formed by such topotactic reductions can be directed by the ordering and identity of the A-site cations. YBaCo(2)O(4.5) adopts a structure consisting of a corner-shared network of square-based pyramidal CoO(5) and distorted tetrahedral CoO(4) units. The structure of LaBaCoO(4.25) is more complex, consisting of an array of square-based pyramidal CoO(5), distorted tetrahedral CoO(4), and square planar CoO(4) units. Magnetic susceptibility and variable-temperature neutron diffraction data reveal that YBaCo(2)O(4.5) adopts a G-type antiferromagnetically ordered structure below T(N) approximately 280 K. LaBaCo(2)O(4.25) also adopts antiferromagnetic order (T(N) approximately 325 K) with ordered moments consistent with the presence of square-planar, low-spin, s = 0, Co(I) centers. A detailed analysis reveals that the different anion vacancy ordered structures adopted by the two REBaCo(2)O(5-x) phases are directed by the relative sizes and ordering of the La(3+) and Y(3+) cations. This suggests that ordered arrangements of A-cations can be used to direct the anion vacancy order in topotactically reduced phases, allowing the preparation of novel metal-oxygen networks containing unusual transition metal coordination environments.

Electrochemical Reduction of CO2 at Metal Electrodes in a Distillable Ionic Liquid.

Science.gov (United States)

Chen, Lu; Guo, Si-Xuan; Li, Fengwang; Bentley, Cameron; Horne, Mike; Bond, Alan M; Zhang, Jie

2016-06-08

The electroreduction of CO2 in the distillable ionic liquid dimethylammonium dimethylcarbamate (dimcarb) has been investigated with 17 metal electrodes. Analysis of the electrolysis products reveals that aluminum, bismuth, lead, copper, nickel, palladium, platinum, iron, molybdenum, titanium and zirconium electroreduce the available protons in dimcarb to hydrogen rather than reducing CO2 . Conversely, indium, tin, zinc, silver and gold are able to catalyze the reduction of CO2 to predominantly carbon monoxide (CO) and to a lesser extent, formate ([HCOO](-) ). In all cases, the applied potential was found to have a minimal influence on the distribution of the reduction products. Overall, indium was found to be the best electrocatalyst for CO2 reduction in dimcarb, with faradaic efficiencies of approximately 45 % and 40 % for the generation of CO and [HCOO](-) , respectively, at a potential of -1.34 V versus Cc(+/0) (Cc(+) =cobaltocenium) employing a dimethylamine to CO2 ratio of less than 1.8:1. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Subsurface oxide plays a critical role in CO2 activation by Cu(111) surfaces to form chemisorbed CO2, the first step in reduction of CO2.

Science.gov (United States)

Favaro, Marco; Xiao, Hai; Cheng, Tao; Goddard, William A; Yano, Junko; Crumlin, Ethan J

2017-06-27

A national priority is to convert CO 2 into high-value chemical products such as liquid fuels. Because current electrocatalysts are not adequate, we aim to discover new catalysts by obtaining a detailed understanding of the initial steps of CO 2 electroreduction on copper surfaces, the best current catalysts. Using ambient pressure X-ray photoelectron spectroscopy interpreted with quantum mechanical prediction of the structures and free energies, we show that the presence of a thin suboxide structure below the copper surface is essential to bind the CO 2 in the physisorbed configuration at 298 K, and we show that this suboxide is essential for converting to the chemisorbed CO 2 in the presence of water as the first step toward CO 2 reduction products such as formate and CO. This optimum suboxide leads to both neutral and charged Cu surface sites, providing fresh insights into how to design improved carbon dioxide reduction catalysts.

Potential energy savings and CO2 emissions reduction of China's cement industry

International Nuclear Information System (INIS)

Ke, Jing; Zheng, Nina; Fridley, David; Price, Lynn; Zhou, Nan

2012-01-01

This study analyzes current energy and carbon dioxide (CO 2 ) emission trends in China's cement industry as the basis for modeling different levels of cement production and rates of efficiency improvement and carbon reduction in 2011–2030. Three cement output projections are developed based on analyses of historical production and physical and macroeconomic drivers. For each of these three production projections, energy savings and CO 2 emission reduction potentials are estimated in a best practice scenario and two continuous improvement scenarios relative to a frozen scenario. The results reveal the potential for cumulative final energy savings of 27.1 to 37.5 exajoules and energy-related direct emission reductions of 3.2 to 4.4 gigatonnes in 2011–2030 under the best practice scenarios. The continuous improvement scenarios produce cumulative final energy savings of 6.0 to 18.9 exajoules and reduce CO 2 emissions by 1.0 to 2.4 gigatonnes. This analysis highlights that increasing energy efficiency is the most important policy measure for reducing the cement industry's energy and emissions intensity, given the current state of the industry and the unlikelihood of significant carbon capture and storage before 2030. In addition, policies to reduce total cement production offer the most direct way of reducing total energy consumption and CO 2 emissions. - Highlights: ► This study models output and efficiency improvements in Chinese cement industry from 2011–2030. ► Energy savings and CO 2 emission reductions estimated for 3 scenarios relative to frozen scenario. ► Results reveal cumulative final energy savings potential of 27.1–37.5 EJ and 3.2–4.4 Gt CO 2 reductions. ► Increasing efficiency is the most important policy for reducing cement energy and emissions intensity.

In situ spectroscopic monitoring of CO2 reduction at copper oxide electrode.

Science.gov (United States)

Wang, Liying; Gupta, Kalyani; Goodall, Josephine B M; Darr, Jawwad A; Holt, Katherine B

2017-04-28

Copper oxide modified electrodes were investigated as a function of applied electrode potential using in situ infrared spectroscopy and ex situ Raman and X-ray photoelectron spectroscopy. In deoxygenated KHCO 3 electrolyte bicarbonate and carbonate species were found to adsorb to the electrode during reduction and the CuO was reduced to Cu(i) or Cu(0) species. Carbonate was incorporated into the structure and the CuO starting material was not regenerated on cycling to positive potentials. In contrast, in CO 2 saturated KHCO 3 solution, surface adsorption of bicarbonate and carbonate was not observed and adsorption of a carbonato-species was observed with in situ infrared spectroscopy. This species is believed to be activated, bent CO 2 . On cycling to negative potentials, larger reduction currents were observed in the presence of CO 2 ; however, less of the charge could be attributed to the reduction of CuO. In the presence of CO 2 CuO underwent reduction to Cu 2 O and potentially Cu, with no incorporation of carbonate. Under these conditions the CuO starting material could be regenerated by cycling to positive potentials.

A highly selective copper-indium bimetallic electrocatalyst for the electrochemical reduction of aqueous CO2to CO

KAUST Repository

Rasul, Shahid

2014-12-23

The challenge in the electrochemical reduction of aqueous carbon dioxide is in designing a highly selective, energy-efficient, and non-precious-metal electrocatalyst that minimizes the competitive reduction of proton to form hydrogen during aqueous CO2 conversion. A non-noble metal electrocatalyst based on a copper-indium (Cu-In) alloy that selectively converts CO2 to CO with a low overpotential is reported. The electrochemical deposition of In on rough Cu surfaces led to Cu-In alloy surfaces. DFT calculations showed that the In preferentially located on the edge sites rather than on the corner or flat sites and that the d-electron nature of Cu remained almost intact, but adsorption properties of neighboring Cu was perturbed by the presence of In. This preparation of non-noble metal alloy electrodes for the reduction of CO2 provides guidelines for further improving electrocatalysis.

Ni–Fe–S Cubanes in CO2 Reduction Electrocatalysis

DEFF Research Database (Denmark)

Varley, J. B.; Hansen, H. A.; Ammitzbøll, Nadia Luciw

2013-01-01

In this work, we perform extensive mechanistic studies of CO2 (electro)reduction by analogs to the active sites of carbon monoxide dehydrogenase (CODH) enzymes. We explore structure–property relationships for different cluster compositions and interpret the results with a model for CO2...... electroreduction we recently developed and applied to transition metal catalysts. Our results validate the effectiveness of the CODH in catalyzing this important reaction and give insight into why specific cluster compositions were adopted by nature....

Performance Limits of Photoelectrochemical CO2 Reduction Based on Known Electrocatalysts and the Case for Two-Electron Reduction Products

DEFF Research Database (Denmark)

Vesborg, Peter Christian Kjærgaard; Seger, Brian

2016-01-01

Solar-drivenreduction of CO2 to solar fuels as an alternative to H2 via water splitting is an intriguing proposition. We modelthe solar-to-fuel (STF) efficiencies using realistic parameters basedon recently reported CO2 reduction catalysts with a highperformance tandem photoabsorber structure. CO...... due to excessiveoverpotentials and poor selectivity. This work considers breakingup the multielectron reduction pathway into individually optimized,separate two-electron steps as a way forward....

Mechanistic Pathway in the Electrochemical Reduction of CO₂ on RuO₂

DEFF Research Database (Denmark)

Karamad, Mohammadreza; Hansen, Heine Anton; Rossmeisl, Jan

2015-01-01

below −0.43 V vs the reversible hydrogen electrode (RHE). On the other hand, at 0.5 ML of CO*, the reduction of formic acid to H2COOH* is the thermodynamically most difficult step and becomes exergonic at potentials below −0.25 V vs RHE. We have found that CO2 reduction activity on RuO2 changes with CO...

Controlling selectivities in CO2 reduction through mechanistic understanding

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiang; Shi, Hui; Szanyi, János

2017-09-11

Catalytic CO2 conversion to energy carriers and intermediates is of utmost importance to energy and environmental goals. However, the lack of fundamental understanding of the reaction mechanism renders designing a selective catalyst inefficient. We performed operando FTIR/SSITKA experiments to understand the correlation between the kinetics of product formation and that of surface species conversion during CO2 reduction over Pd/Al2O3 catalysts. We found that the rate-determining step for CO formation is the conversion of adsorbed formate, while that for CH4 formation is the hydrogenation of adsorbed carbonyl. The balance of the hydrogenation kinetics between adsorbed formates and carbonyls governs the selectivities to CH4 and CO. We demonstrated how this knowledge can be used to design catalysts to achieve high selectivities to desired products.

Reduction of CO2 emissions during cement clinker burning : Part 2 = Ein Beitrag zur Reduzierung der CO2-Emissionen beim Zementklinkerbrand; Teil 2

NARCIS (Netherlands)

Vogel, S.; Kolditz, K.; Beilmann, F.; Finger, F.A.; Ott-Reinhardt, D.; Kralisch, D.

2013-01-01

The aim of the research project entitled "New technology in cement production for reducing CO2 emissions" sponsored by the German Federal Environmental Foundation was to lower the CO2 emissions during clinker burning. A possible reduction, relative to an industrial example, of up to 21 % in the

Catalytic conversion of CO, NO and SO2 on supported sulfide catalysts. Part 2. Catalytic reduction of NO and SO2 by CO

International Nuclear Information System (INIS)

Zhuang, S.-X.; Yamazaki, M.; Omata, K.; Takahashi, Y.; Yamada, M.

2001-01-01

To investigate the possibility of simultaneous catalytic reduction of NO and SO 2 by CO, reactions of NO, NO-CO, and NO-SO 2 -CO were performed on γ-alumina-supported sulfides of transition metals including Co, Mo, CoMo and FeMo. NO was decomposed into N 2 O and N 2 accompanied with the formation of SO 2 ; this serious oxidation of lattice sulfur resulted in the deactivation of the catalysts. The addition of CO to the NO stream suppressed SO 2 formation and yielded COS instead. A stoichiometric conversion of NO and CO to N 2 and CO 2 was observed above 350C on the CoMo and the FeMo catalysts. Although the CO addition lengthened catalyst life, it was not enough to maintain activity. After the NO-CO reaction, an XPS analysis showed the growth of Mo 6+ and SO 4 2- peaks, especially for the sulfided FeMo/Al 2 O 3 ; the FeMo catalyst underwent strong oxidation in the NO-CO reaction. The NO and the NO-CO reactions proceeded non-catalytically, consuming catalyst lattice sulfur to yield SO 2 or COS. The addition of SO 2 in the NO-CO system enabled in situ regeneration of the catalysts; the catalysts oxidized through abstraction of lattice sulfur experienced anew reduction and sulfurization through the SO 2 -CO reaction at higher temperature. NO and SO 2 were completely and catalytically converted at 400C on the sulfided CoMo/Al 2 O 3 . By contrast, the sulfided FeMo/Al 2 O 3 was easily oxidized by NO and hardly re-sulfided under the test conditions. Oxidation states of the metals before and after the reactions were determined. Silica and titania-supported CoMo catalysts were also evaluated to study support effects

CO2 Reduction Catalyzed by Nitrogenase: Pathways to Formate, Carbon Monoxide, and Methane

OpenAIRE

Khadka, Nimesh; Dean, Dennis R.; Smith, Dayle; Hoffman, Brian M.; Raugei, Simone; Seefeldt, Lance C.

2016-01-01

The reduction of N2 to NH3 by Mo-dependent nitrogenase at its active-site metal cluster FeMo-cofactor utilizes reductive elimination (re) of Fe-bound hydrides with obligatory loss of H2 to activate the enzyme for binding/reduction of N2. Earlier work showed that wild type nitrogenase and a nitrogenase having amino acid substitutions in the MoFe protein near FeMo-cofactor can catalytically reduce CO2 by 2 or 8 electrons/protons to carbon monoxide (CO) and methane (CH4) at low rates. Here, it i...

Estimate of Possible CO2 Emission Reduction in Slovenia

International Nuclear Information System (INIS)

Plavcak, V.-P.; Jevsek, F.; Tirsek, A.

1998-01-01

The first estimation of possible CO 2 emission reduction, according to the obligations from Kyoto Protocol, is prepared. The results show that the required 8% reduction of greenhouses gases in Slovenia in the period from 2008 to 2012 with regard to year 1986 will require a through analytical treatment not only in electric power sector but also in transport and industry sectors, which are the main pollutants. (author)

High-throughput synthesis of mixed-metal electrocatalysts for CO{sub 2} reduction

Energy Technology Data Exchange (ETDEWEB)

He, Jingfu; Dettelbach, Kevan E.; Li, Tengfei [Department of Chemistry, The University of British Columbia, Vancouver, BC (Canada); Salvatore, Danielle A. [Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC (Canada); Berlinguette, Curtis P. [Department of Chemistry, The University of British Columbia, Vancouver, BC (Canada); Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC (Canada)

2017-05-22

The utilization of CO{sub 2} as a feedstock requires fundamental breakthroughs in catalyst design. The efficiencies and activities of pure metal electrodes towards the CO{sub 2} reduction reaction are established, but the corresponding data on mixed-metal systems are not as well developed. In this study we show that the near-infrared driven decomposition (NIRDD) of solution-deposited films of metal salts and subsequent electrochemical reduction offers the unique opportunity to form an array of mixed-metal electrocatalyst coatings with excellent control of the metal stoichiometries. This synthetic method enabled us to develop an empirical structure-property correlation to help inform the development of optimized CO{sub 2} catalyst compositions. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

CO2 sequestration. World CO2 emission reduction by forest plantations on agricultural land up to 2050

International Nuclear Information System (INIS)

Dameron, V.; Barbier, C.; Riedacker, A.

2005-01-01

The main objective of this study was to determine the possible contribution on CO 2 emission reductions of new forest plantations on agricultural land which may become available in the world from now to 2050. Emission reductions have been calculated by taking into account potential changes in carbon stocks on afforested land (in biomass and soil) and replacement with biomass of fossil fuel and material such as steel, aluminium or concrete. Increase of carbon stocks in wood as building material and final conversion of wood recycled from buildings into energy to replace fossil fuel have also been taken into account. CO 2 emission reductions (or carbon benefits) from afforested agricultural land become significant only after 2030 or 2050, and even at a later stage with long rotations. In the case of the latter, about 100 years are needed to get the full benefits. Forest plantations can therefore only be considered as long term options

Reduction of emissions and geological storage of CO{sub 2}. Innovation an industrial stakes; Reduction des emissions et stockage geologique du CO{sub 2}. Innovation et enjeux industriels

Energy Technology Data Exchange (ETDEWEB)

Mandil, C.; Podkanski, J.; Socolow, R.; Dron, D.; Reiner, D.; Horrocks, P.; Fernandez Ruiz, P.; Dechamps, P.; Stromberg, L.; Wright, I.; Gazeau, J.C.; Wiederkehr, P.; Morcheoine, A.; Vesseron, P.; Feron, P.; Feraud, A.; Torp, N.T.; Christensen, N.P.; Le Thiez, P.; Czernichowski, I.; Hartman, J.; Roulet, C.; Roberts, J.; Zakkour, P.; Von Goerne, G.; Armand, R.; Allinson, G.; Segalen, L.; Gires, J.M.; Metz, B.; Brillet, B

2005-07-01

An international symposium on the reduction of emissions and geological storage of CO{sub 2} was held in Paris from 15 to 16 September 2005. The event, jointly organized by IFP, ADEME and BRGM, brought together over 400 people from more than 25 countries. It was an opportunity to review the international stakes related to global warming and also to debate ways of reducing CO{sub 2} emissions, taking examples from the energy and transport sectors. The last day was dedicated to technological advances in the capture and geological storage of CO{sub 2} and their regulatory and economic implications. This document gathers the available transparencies and talks presented during the colloquium: Opening address by F. Loos, French Minister-delegate for Industry; Session I - Greenhouse gas emissions: the international stakes. Outlook for global CO{sub 2} emissions. The global and regional scenarios: Alternative scenarios for energy use and CO{sub 2} emissions until 2050 by C. Mandil and J. Podkanski (IEA), The stabilization of CO{sub 2} emissions in the coming 50 years by R. Socolow (Princeton University). Evolution of the international context: the stakes and 'factor 4' issues: Costs of climate impacts and ways towards 'factor 4' by D. Dron (ENS Mines de Paris), CO{sub 2} emissions reduction policy: the situation in the United States by D. Reiner (MIT/Cambridge University), Post-Kyoto scenarios by P. Horrocks (European Commission), Possibilities for R and D in CO{sub 2} capture and storage in the future FP7 program by P. Fernandez Ruiz and P. Dechamps (European Commission). Session II - CO{sub 2} emission reductions in the energy and transport sectors. Reducing CO{sub 2} emissions during the production and conversion of fossil energies (fixed installations): Combined cycles using hydrogen by G. Haupt (Siemens), CO{sub 2} emission reductions in the oil and gas industry by I. Wright (BP). Reducing CO{sub 2} emissions in the transport sector: Sustainable

The global warming game - simulations of a CO2 reduction agreement

International Nuclear Information System (INIS)

Fankhauser, S.; Kverndokk, S.

1992-06-01

The paper analyses incentives for and the benefits of a possible international cooperation to reduce CO-2-emissions. The negotiations are modeled as a (static) reciprocal-externality-game in CO 2 -emissions between five world regions. CO 2 -emissions affect the players in two ways: First, each country's income depends (via energy inputs) on the amount of CO 2 emitted. On the other hand, emissions may cause future damage due to climate change. Without cooperation, each player maximizes its net benefits in setting marginal income equal to its marginal damage cost (Nash equilibrium). Under full cooperation marginal income equals the sum of the marginal damages (social optimum). The paper presents simulations of these two equilibria. Compared to the situation where no attention is paid to the greenhouse effect (the business as usual scenario), emission reductions under the Nash equilibrium can be interpreted as incentives for unilateral actions. According to the simulation results, this can only be expected from OECD countries. The results also imply that a socially optimal treaty, while clearly beneficial for the world in its entirety, may only be achieved if side payments are offered to at least China and the former Soviet Union, and probably the USA. The optimal global emission reductions in this study are on average lower than the reductions recommended by international conferences. 34 refs., 2 figs., 9 tabs

CuZn Alloy- Based Electrocatalyst for CO2 Reduction

KAUST Repository

Alazmi, Amira

2014-01-01

, especially when the electronic energy is derived from renewable energies, such as solar, wind, geo-thermal and tidal. To achieve this goal, the development of an efficient electrocatalyst for CO2 reduction is essential. In this thesis, studies on CuZn alloys

Assesment of Energy Options for CO2 Emission Reduction

International Nuclear Information System (INIS)

Cavlina, Nikola

2014-01-01

Since the 1992 Earth Summit in Rio de Janeiro, global anthropogenic CO 2 emissions grew by 52% which caused an increase in 10.8% in the CO 2 concentration in the atmosphere, and it tipped the 400 ppm mark in May 2013. The Fifth Assessment Report on climate impacts from the Intergovernmental Panel on Climate Change (IPCC) confirmed earlier warnings that climate change is already stressing human communities, agriculture, and natural ecosystems, and the effects are likely to increase in the future. While European Union has long been committed to lowering carbon emissions, this places additional pressure on current EU goals for energy sector that includes significant reduction of CO 2 emissions. Current EU commitment has been formalized in so-called '20-20-20' plan, reducing carbon emissions, increasing energy efficiency and increasing energy production from renewables by 20% by 2020. Some EU member states are even more ambitious, like United Kingdom, planning to reduce carbon emissions by 80% by 2050. Bulk of carbon reduction will have to be achived in energy sector. In the power industry, most popular solution is use of solar and wind power. Since their production varies significantly during the day, for the purpose of base-load production they can be paired with gas-fired power plant. Other possible CO 2 -free solution is nuclear power plant. In this invited lecture, predicted cost of energy production for newly bulit nuclear power plant and newly built combination of wind or solar and gas-fired power plant are compared. Comparison was done using Levelized Unit of Energy Cost (LUEC). Calculations were performed using the Monte Carlo method. For input parameters that have biggest uncertainty (gas cost, CO 2 emission fee) those uncertainties were addressed not only through probability distribution around predicted value, but also through different scenarious. (author)

Enhanced Photocatalytic Reduction of CO2 to CO through TiO2 Passivation of InP in Ionic Liquids.

Science.gov (United States)

Zeng, Guangtong; Qiu, Jing; Hou, Bingya; Shi, Haotian; Lin, Yongjing; Hettick, Mark; Javey, Ali; Cronin, Stephen B

2015-09-21

A robust and reliable method for improving the photocatalytic performance of InP, which is one of the best known materials for solar photoconversion (i.e., solar cells). In this article, we report substantial improvements (up to 18×) in the photocatalytic yields for CO2 reduction to CO through the surface passivation of InP with TiO2 deposited by atomic layer deposition (ALD). Here, the main mechanisms of enhancement are the introduction of catalytically active sites and the formation of a pn-junction. Photoelectrochemical reactions were carried out in a nonaqueous solution consisting of ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4), dissolved in acetonitrile, which enables CO2 reduction with a Faradaic efficiency of 99% at an underpotential of +0.78 V. While the photocatalytic yield increases with the addition of the TiO2 layer, a corresponding drop in the photoluminescence intensity indicates the presence of catalytically active sites, which cause an increase in the electron-hole pair recombination rate. NMR spectra show that the [EMIM](+) ions in solution form an intermediate complex with CO2(-), thus lowering the energy barrier of this reaction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of CO2 emission reduction strategy from in-use gasoline vehicle

Science.gov (United States)

Choudhary, Arti; Gokhale, Sharad

2016-04-01

On road transport emissions is kicking off in Indian cities due to high levels of urbanization and economic growth during the last decade in Indian subcontinent. In 1951, about 17% of India's population were living in urban areas that increased to 32% in 2011. Currently, India is fourth largest Green House Gas (GHG) emitter in the world, with its transport sector being the second largest contributor of CO2 emissions. For achieving prospective carbon reduction targets, substantial opportunity among in-use vehicle is necessary to quantify. Since, urban traffic flow and operating condition has significant impact on exhaust emission (Choudhary and Gokhale, 2016). This study examined the influence of vehicular operating kinetics on CO2 emission from predominant private transportation vehicles of Indian metropolitan city, Guwahati. On-board instantaneous data were used to quantify the impact of CO2 emission on different mileage passenger cars and auto-rickshaws at different times of the day. Further study investigates CO2 emission reduction strategies by using International Vehicle Emission (IVE) model to improve co-benefit in private transportation by integrated effort such as gradual phase-out of inefficient vehicle and low carbon fuel. The analysis suggests that fuel type, vehicles maintenance and traffic flow management have potential for reduction of urban sector GHG emissions. Keywords: private transportation, CO2, instantaneous emission, IVE model Reference Choudhary, A., Gokhale, S. (2016). Urban real-world driving traffic emissions during interruption and congestion. Transportation Research Part D: Transport and Environment 43: 59-70.

Northern California CO₂ Reduction Project

Energy Technology Data Exchange (ETDEWEB)

Hymes, Edward [C6 Resources LLC, Houston, TX (United States)

2010-06-16

C6 Resources LLC, a wholly owned subsidiary of Shell Oil Company, worked with the US Department of Energy (DOE) under a Cooperative Agreement to develop the Northern California CO₂ Reduction Project. The objective of the Project is to demonstrate the viability of using Carbon Capture and Sequestration (CCS) to reduce existing greenhouse gas emissions from industrial sources on a large-scale. The Project will capture more than 700,000 metric tonnes of CO₂ per year, which is currently being vented to the atmosphere from the Shell Martinez Refinery in Contra Costa County. The CO₂ will be compressed and dehydrated at the refinery and then transported via pipeline to a sequestration site in a rural area in neighboring Solano County. The CO₂ will be sequestered into a deep saline formation (more than two miles underground) and will be monitored to assure secure, long-term containment. The pipeline will be designed to carry as much as 1,400,000 metric tonnes of CO₂ per year, so additional capacity will be available to accommodate CO₂ captured from other industrial sources. The Project is expected to begin operation in 2015. The Project has two distinct phases. The overall objective of Phase 1 was to develop a fully definitive design basis for the Project. The Cooperative Agreement with the DOE provided cost sharing for Phase 1 and the opportunity to apply for additional DOE cost sharing for Phase 2, comprising the design, construction and operation of the Project. Phase 1 has been completed. DOE co-funding is provided by the American Recovery and Reinvestment Act (ARRA) of 2009. As prescribed by ARRA, the Project will stimulate the local economy by creating manufacturing, transportation, construction, operations, and management jobs while addressing the need to reduce greenhouse gas emissions at an accelerated pace. The Project, which will also assist in meeting the CO₂ reduction requirements set

Light-induced cation exchange for copper sulfide based CO2 reduction.

Science.gov (United States)

Manzi, Aurora; Simon, Thomas; Sonnleitner, Clemens; Döblinger, Markus; Wyrwich, Regina; Stern, Omar; Stolarczyk, Jacek K; Feldmann, Jochen

2015-11-11

Copper(I)-based catalysts, such as Cu2S, are considered to be very promising materials for photocatalytic CO2 reduction. A common synthesis route for Cu2S via cation exchange from CdS nanocrystals requires Cu(I) precursors, organic solvents, and neutral atmosphere, but these conditions are not compatible with in situ applications in photocatalysis. Here we propose a novel cation exchange reaction that takes advantage of the reducing potential of photoexcited electrons in the conduction band of CdS and proceeds with Cu(II) precursors in an aqueous environment and under aerobic conditions. We show that the synthesized Cu2S photocatalyst can be efficiently used for the reduction of CO2 to carbon monoxide and methane, achieving formation rates of 3.02 and 0.13 μmol h(-1) g(-1), respectively, and suppressing competing water reduction. The process opens new pathways for the preparation of new efficient photocatalysts from readily available nanostructured templates.

Synthesis and photocatalytic CO2 reduction performance of Cu2O/Coal-based carbon nanoparticle composites

Science.gov (United States)

Dedong, Zhang; Maimaiti, Halidan; Awati, Abuduheiremu; Yisilamu, Gunisakezi; Fengchang, Sun; Ming, Wei

2018-05-01

The photocatalytic reduction of CO2 into hydrocarbons provides a promising approach to overcome the challenges of environmental crisis and energy shortage. Here we fabricated a cuprous oxide (Cu2O) based composite photocatalyst consisting of Cu2O/carbon nanoparticles (CNPs). To prepare the CNPs, coal samples from Wucaiwan, Xinjiang, China, were first treated with HNO3, followed by hydrogen peroxide (H2O2) oxidation to strip nanocrystalline carbon from coal. After linking with oxygen-containing group such as hydroxyl, coal-based CNPs with sp2 carbon structure and multilayer graphene lattice structure were synthesized. Subsequently, the CNPs were loaded onto the surface of Cu2O nanoparticles prepared by in-situ reduction of copper chloride (CuCl2·2H2O). The physical properties and chemical structure of the Cu2O/CNPs as well as photocatalytic activity of CO2/H2O reduction into CH3OH were measured. The results demonstrate that the Cu2O/CNPs are composed of spherical particles with diameter of 50 nm and mesoporous structure, which are suitable for CO2 adsorption. Under illumination of visible light, electron-hole pairs are generated in Cu2O. Thanks to the CNPs, the fast recombination of electron-hole pairs is suppressed. The energy gradient formed on the surface of Cu2O/CNPs facilitates the efficient separation of electron-hole pairs for CO2 reduction and H2O oxidation, leading to enhanced photocatalytic activity.

Simultaneous Reduction of CO 2 and Splitting of H 2 O by a Single Immobilized Cobalt Phthalocyanine Electrocatalyst

KAUST Repository

Morlanés, Natalia

2016-04-12

Perfluorinated cobalt phthalocyanine (CoFPc) immobilized on carbon electrodes was found to electrocatalyze the reduction of CO2 selectively to CO in an aqueous solution. The conversion of CO2 became apparent at -0.5 V vs RHE, and the Faradaic efficiency for the CO production reached as high as 93% at -0.8 V vs RHE. Highly stable electrolysis of CO2/H2O into CO/O2 was achieved for 12 h by applying the same catalyst as the cathode for CO2 reduction and the anode for water oxidation. This result indicates the highly robust nature of the CoFPc at wide range of potentials from -0.9 V to +2.2 V vs RHE, demonstrating the potential bipolar electrolytic system for CO2/H2O electrolysis, using the single-site molecular CoFPc-based electrocatalyst, which is simple, inexpensive, robust, and efficient. © 2016 American Chemical Society.

Coupled Metal/Oxide Catalysts with Tunable Product Selectivity for Electrocatalytic CO2 Reduction.

Science.gov (United States)

Huo, Shengjuan; Weng, Zhe; Wu, Zishan; Zhong, Yiren; Wu, Yueshen; Fang, Jianhui; Wang, Hailiang

2017-08-30

One major challenge to the electrochemical conversion of CO 2 to useful fuels and chemical products is the lack of efficient catalysts that can selectively direct the reaction to one desirable product and avoid the other possible side products. Making use of strong metal/oxide interactions has recently been demonstrated to be effective in enhancing electrocatalysis in the liquid phase. Here, we report one of the first systematic studies on composition-dependent influences of metal/oxide interactions on electrocatalytic CO 2 reduction, utilizing Cu/SnO x heterostructured nanoparticles supported on carbon nanotubes (CNTs) as a model catalyst system. By adjusting the Cu/Sn ratio in the catalyst material structure, we can tune the products of the CO 2 electrocatalytic reduction reaction from hydrocarbon-favorable to CO-selective to formic acid-dominant. In the Cu-rich regime, SnO x dramatically alters the catalytic behavior of Cu. The Cu/SnO x -CNT catalyst containing 6.2% of SnO x converts CO 2 to CO with a high faradaic efficiency (FE) of 89% and a j CO of 11.3 mA·cm -2 at -0.99 V versus reversible hydrogen electrode, in stark contrast to the Cu-CNT catalyst on which ethylene and methane are the main products for CO 2 reduction. In the Sn-rich regime, Cu modifies the catalytic properties of SnO x . The Cu/SnO x -CNT catalyst containing 30.2% of SnO x reduces CO 2 to formic acid with an FE of 77% and a j HCOOH of 4.0 mA·cm -2 at -0.99 V, outperforming the SnO x -CNT catalyst which only converts CO 2 to formic acid in an FE of 48%.

Photocatalytic reduction of CO2 to CO over copper decorated g-C3N4 nanosheets with enhanced yield and selectivity

Science.gov (United States)

Shi, Guodong; Yang, Lin; Liu, Zhuowen; Chen, Xiao; Zhou, Jianqing; Yu, Ying

2018-01-01

Photocatalytic reduction of CO2 to fuel has attracted considerable attention due to the consumption of fossil fuels and serious environmental problems. Although there are many photocatalysts reported for CO2 reduction, the improvement of activity and selectivity is still in great need of. In this work, a series of Cu nanoparticle decorated g-C3N4 nanosheets with different Cu loadings were fabricated by a facile secondary calcination and subsequent microwave hydrothermal method. The designed catalysts shown good photocatalytic activity and selectivity for CO2 reduction to CO. The optimal sample exhibited a 3-fold augmentation of the CO yield in comparison with pristine g-C3N4 under visible light. It is revealed that with the loading of Cu nanoparticles, the resulting photocatalyst possessed an improved charge carrier transfer and separation efficiency as well as increased surface reactive sites, resulting in a significant enhancement of CO yield. It is anticipated that the designed Cu/C3N4 photocatalyst may provide new insights for two dimensional layer materials and non-noble particles applied to CO2 reduction.

Progress and Perspective of Electrocatalytic CO2 Reduction for Renewable Carbonaceous Fuels and Chemicals.

Science.gov (United States)

Zhang, Wenjun; Hu, Yi; Ma, Lianbo; Zhu, Guoyin; Wang, Yanrong; Xue, Xiaolan; Chen, Renpeng; Yang, Songyuan; Jin, Zhong

2018-01-01

The worldwide unrestrained emission of carbon dioxide (CO 2 ) has caused serious environmental pollution and climate change issues. For the sustainable development of human civilization, it is very desirable to convert CO 2 to renewable fuels through clean and economical chemical processes. Recently, electrocatalytic CO 2 conversion is regarded as a prospective pathway for the recycling of carbon resource and the generation of sustainable fuels. In this review, recent research advances in electrocatalytic CO 2 reduction are summarized from both experimental and theoretical aspects. The referred electrocatalysts are divided into different classes, including metal-organic complexes, metals, metal alloys, inorganic metal compounds and carbon-based metal-free nanomaterials. Moreover, the selective formation processes of different reductive products, such as formic acid/formate (HCOOH/HCOO - ), monoxide carbon (CO), formaldehyde (HCHO), methane (CH 4 ), ethylene (C 2 H 4 ), methanol (CH 3 OH), ethanol (CH 3 CH 2 OH), etc. are introduced in detail, respectively. Owing to the limited energy efficiency, unmanageable selectivity, low stability, and indeterminate mechanisms of electrocatalytic CO 2 reduction, there are still many tough challenges need to be addressed. In view of this, the current research trends to overcome these obstacles in CO 2 electroreduction field are summarized. We expect that this review will provide new insights into the further technique development and practical applications of CO 2 electroreduction.

A supply chain optimization framework for CO2 emission reduction : Case of the Netherlands

NARCIS (Netherlands)

Kalyanarengan Ravi, N.; Zondervan, E.; van Sint Annaland, M.; Fransoo, J.C.; Grievink, J.; Claus, T.; Herrmann, F.; Manitz, M.; Rose, O.

2016-01-01

A major challenge for the industrial deployment of a CO2 emission reduction methodology is to reduce the overall cost and the integration of all the nodes in the supply chain for CO2 emission reduction. In this work, we develop a mixed integer linear optimization model that selects appropriate

Reduction of emissions and geological storage of CO2. Innovation an industrial stakes

International Nuclear Information System (INIS)

Mandil, C.; Podkanski, J.; Socolow, R.; Dron, D.; Reiner, D.; Horrocks, P.; Fernandez Ruiz, P.; Dechamps, P.; Stromberg, L.; Wright, I.; Gazeau, J.C.; Wiederkehr, P.; Morcheoine, A.; Vesseron, P.; Feron, P.; Feraud, A.; Torp, N.T.; Christensen, N.P.; Le Thiez, P.; Czernichowski, I.; Hartman, J.; Roulet, C.; Roberts, J.; Zakkour, P.; Von Goerne, G.; Armand, R.; Allinson, G.; Segalen, L.; Gires, J.M.; Metz, B.; Brillet, B.

2005-01-01

An international symposium on the reduction of emissions and geological storage of CO 2 was held in Paris from 15 to 16 September 2005. The event, jointly organized by IFP, ADEME and BRGM, brought together over 400 people from more than 25 countries. It was an opportunity to review the international stakes related to global warming and also to debate ways of reducing CO 2 emissions, taking examples from the energy and transport sectors. The last day was dedicated to technological advances in the capture and geological storage of CO 2 and their regulatory and economic implications. This document gathers the available transparencies and talks presented during the colloquium: Opening address by F. Loos, French Minister-delegate for Industry; Session I - Greenhouse gas emissions: the international stakes. Outlook for global CO 2 emissions. The global and regional scenarios: Alternative scenarios for energy use and CO 2 emissions until 2050 by C. Mandil and J. Podkanski (IEA), The stabilization of CO 2 emissions in the coming 50 years by R. Socolow (Princeton University). Evolution of the international context: the stakes and 'factor 4' issues: Costs of climate impacts and ways towards 'factor 4' by D. Dron (ENS Mines de Paris), CO 2 emissions reduction policy: the situation in the United States by D. Reiner (MIT/Cambridge University), Post-Kyoto scenarios by P. Horrocks (European Commission), Possibilities for R and D in CO 2 capture and storage in the future FP7 program by P. Fernandez Ruiz and P. Dechamps (European Commission). Session II - CO 2 emission reductions in the energy and transport sectors. Reducing CO 2 emissions during the production and conversion of fossil energies (fixed installations): Combined cycles using hydrogen by G. Haupt (Siemens), CO 2 emission reductions in the oil and gas industry by I. Wright (BP). Reducing CO 2 emissions in the transport sector: Sustainable transport systems by P. Wiederkehr (EST International), The prospects for reducing

Influence of Operational Parameters on the Photocatalytic Activity of Powdered TiO2 for the Reduction of CO2

Directory of Open Access Journals (Sweden)

Oman Zuas

2014-07-01

Full Text Available In this report, the results from a study on the influence of operational parameters on TiO2 photocatalytic activity for CO2 reduction under an ultraviolet-visible (UV-vis illumination are presented. The results indicated that the TiO2 was found to be active for CO2 reduction with CH3OH as the major products, while other minor products (CO, CH4, and C2H4 were also detected. In addition, the formation of such reduction products was obviously influenced by the operational parameters. Under this study, the optimum operational parameters for CO2 reduction at 298 °K were determined to be: NaOH concentration 0.2 M, TiO2 dosage 2 g/L, volume of the reaction media 75 mL, the pressure of system 800 kPa. It was also found that the increase in UV-vis illumination time have increased the yield of product formation. A possible reaction pathway for the formation of the reduction products is also discussed.

A supply chain optimization framework for CO2 emission reduction: Case of the Netherlands

OpenAIRE

Kalyanarengan Ravi, N.; Zondervan, E.; van Sint Annaland, M.; Fransoo, J.C.; Grievink, J.; Claus, T.; Herrmann, F.; Manitz, M.; Rose, O.

2016-01-01

A major challenge for the industrial deployment of a CO2 emission reduction methodology is to reduce the overall cost and the integration of all the nodes in the supply chain for CO2 emission reduction. In this work, we develop a mixed integer linear optimization model that selects appropriate sources, capture process, transportation network and CO2 storage sites and optimize for a minimum overall cost. Initially, we screen the sources and storage options available in the Netherlands at diffe...

Surface-reconstructed Cu Electrode via a Facile Electrochemical Anodization-Reduction Process for Low Overpotential CO 2 reduction

KAUST Repository

Min, Shixiong; Yang, Xiulin; Lu, Ang-Yu; Tseng, Chien-Chih; Hedhili, Mohamed N.; Lai, Zhiping; Li, Lain-Jong; Huang, Kuo-Wei

2017-01-01

A high-surface-area Cu electrode, fabricated by a simple electrochemical anodization-reduction method, exhibits high activity and selectivity for CO2 reduction at low overpotential in 0.1 M KHCO3 solution. A faradaic efficiency of 37% for HCOOH

An analysis of energy strategies for CO2 emission reduction in China. Case studies by MARKAL model

International Nuclear Information System (INIS)

Li Guangya

1994-12-01

The China's energy system has been analyzed by using the MARKAL model in this study and the time period is from the year 1990 to 2050. The MARKAL model is applied here to evaluate the cost effective energy strategies for CO 2 emission reduction in China. Firstly the Reference Energy System (RES) of China and its database were established, and the useful energy demand was projected on the basis of China's economic target and demographic forecasting. Four scenarios, BASE1-BASE4 were defined with different assumptions of crude oil and natural uranium availability. Analytical results show that without CO 2 emission constrains coal consumption will continue to hold a dominant position in primary energy supply, and CO 2 emissions in 2050 will be 9.55 BtCO 2 and 10.28 BtCO 2 with different natural uranium availability. Under the CO 2 emission constraints, nuclear and renewable energy will play important roles in CO 2 emission reduction, and feasible maximum CO 2 emission reduction estimated by this study is 3.16 BtCO 2 in 2050. The cumulative CO 2 emission from 1990 to 2050 will be 418.25 BtCO 2 and 429.16 BtCO 2 with different natural uranium availability. Total feasible maximum CO 2 emission reduction from 1990 to 2050 is 95.97 BtCO 2 . (author)

CO2 reduction: is increasing the diesel share the way to go?

NARCIS (Netherlands)

Rijkeboer, R.C.; Havenith, C.; Baarbe, H.L.

1998-01-01

Different scenarios have been compared for the future reduction of CO2-emission under real-world driving conditions. A significant shift towards diesel appears hardly to benefit the CO2 but would carry a real NOx penalty. Introduction of DI petrol engines and a shift towards gaseous fuels for s.i.

Surface-reconstructed Cu Electrode via a Facile Electrochemical Anodization-Reduction Process for Low Overpotential CO 2 reduction

KAUST Repository

Min, Shixiong

2017-03-21

A high-surface-area Cu electrode, fabricated by a simple electrochemical anodization-reduction method, exhibits high activity and selectivity for CO2 reduction at low overpotential in 0.1 M KHCO3 solution. A faradaic efficiency of 37% for HCOOH and 27% for CO production was achieved with the current density of 1.5 mA cm-2 at −0.64 V vs. RHE, much higher than that of polycrystalline Cu. The enhanced catalytic performance is a result of the formation of the high electrochemical active surface area and high density of preferred low-index facets.

The global warming game - simulations of a CO[sub 2] reduction agreement

Energy Technology Data Exchange (ETDEWEB)

Fankhauser, S [Centre for Social and Economic Research on the Global Environment, London (United Kingdom); Kverndokk, S [Stiftelsen for Samfunns- og Naeringslivsforskning, Oslo (Norway)

1992-06-01

The paper analyses incentives for and the benefits of a possible international cooperation to reduce CO-2-emissions. The negotiations are modeled as a (static) reciprocal-externality-game in CO[sub 2]-emissions between five world regions. CO[sub 2]-emissions affect the players in two ways: First, each country's income depends (via energy inputs) on the amount of CO[sub 2] emitted. On the other hand, emissions may cause future damage due to climate change. Without cooperation, each player maximizes its net benefits in setting marginal income equal to its marginal damage cost (Nash equilibrium). Under full cooperation marginal income equals the sum of the marginal damages (social optimum). The paper presents simulations of these two equilibria. Compared to the situation where no attention is paid to the greenhouse effect (the business as usual scenario), emission reductions under the Nash equilibrium can be interpreted as incentives for unilateral actions. According to the simulation results, this can only be expected from OECD countries. The results also imply that a socially optimal treaty, while clearly beneficial for the world in its entirety, may only be achieved if side payments are offered to at least China and the former Soviet Union, and probably the USA. The optimal global emission reductions in this study are on average lower than the reductions recommended by international conferences. 34 refs., 2 figs., 9 tabs.

Simultaneous Reduction of CO 2 and Splitting of H 2 O by a Single Immobilized Cobalt Phthalocyanine Electrocatalyst

KAUST Repository

Morlanes, Natalia Sanchez; Takanabe, Kazuhiro; Rodionov, Valentin

2016-01-01

Perfluorinated cobalt phthalocyanine (CoFPc) immobilized on carbon electrodes was found to electrocatalyze the reduction of CO2 selectively to CO in an aqueous solution. The conversion of CO2 became apparent at -0.5 V vs RHE, and the Faradaic

Organic reactions for the electrochemical and photochemical production of chemical fuels from CO2--The reduction chemistry of carboxylic acids and derivatives as bent CO2 surrogates.

Science.gov (United States)

Luca, Oana R; Fenwick, Aidan Q

2015-11-01

The present review covers organic transformations involved in the reduction of CO2 to chemical fuels. In particular, we focus on reactions of CO2 with organic molecules to yield carboxylic acid derivatives as a first step in CO2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO2 reactivity from organic chemistry, organocatalysis, surface science and electrocatalysis. We point out some possible non-faradaic chemical reactions that may contribute to product distributions in the production of solar fuels from CO2. These reactions may be accelerated by thermal effects such as resistive heating and illumination. Copyright © 2015 Elsevier B.V. All rights reserved.

CO_2 emissions and energy intensity reduction allocation over provincial industrial sectors in China

International Nuclear Information System (INIS)

Wu, Jie; Zhu, Qingyuan; Liang, Liang

2016-01-01

Highlights: • DEA is used to evaluate the energy and environmental efficiency of 30 provincial industrial sector in China. • A new DEA-based model is proposed to allocate the CO_2 emissions and energy intensity reduction targets. • The context-dependent DEA is used to characterize the production plans. - Abstract: High energy consumption by the industry of developing countries has led to the problems of increasing emission of greenhouse gases (GHG) (primarily CO_2) and worsening energy shortages. To address these problems, many mitigation measures have been utilized. One major measure is to mandate fixed reductions of GHG emission and energy consumption. Therefore, it is important for each developing country to disaggregate their national reduction targets into targets for various geographical parts of the country. In this paper, we propose a DEA-based approach to allocate China’s national CO_2 emissions and energy intensity reduction targets over Chinese provincial industrial sectors. We firstly evaluate the energy and environmental efficiency of Chinese industry considering energy consumption and GHG emissions. Then, considering the necessity of mitigating GHG emission and energy consumption, we develop a context-dependent DEA technique which can better characterize the changeable production with reductions of CO_2 emission and energy intensity, to help allocate the national reduction targets over provincial industrial sectors. Our empirical study of 30 Chinese regions for the period 2005–2010 shows that the industry of China had poor energy and environmental efficiency. Considering three major geographical areas, eastern China’s industrial sector had the highest efficiency scores while in this aspect central and western China were similar to each other at a lower level. Our study shows that the most effective allocation of the national reduction target requires most of the 30 regional industrial to reduce CO_2 emission and energy intensity, while a

Rational Design of a Hierarchical Tin Dendrite Electrode for Efficient Electrochemical Reduction of CO2.

Science.gov (United States)

Won, Da Hye; Choi, Chang Hyuck; Chung, Jaehoon; Chung, Min Wook; Kim, Eun-Hee; Woo, Seong Ihl

2015-09-21

Catalysis is a key technology for the synthesis of renewable fuels through electrochemical reduction of CO2 . However, successful CO2 reduction still suffers from the lack of affordable catalyst design and understanding the factors governing catalysis. Herein, we demonstrate that the CO2 conversion selectivity on Sn (or SnOx /Sn) electrodes is correlated to the native oxygen content at the subsurface. Electrochemical analyses show that the reduced Sn electrode with abundant oxygen species effectively stabilizes a CO2 (.-) intermediate rather than the clean Sn surface, and consequently results in enhanced formate production in the CO2 reduction. Based on this design strategy, a hierarchical Sn dendrite electrode with high oxygen content, consisting of a multi-branched conifer-like structure with an enlarged surface area, was synthesized. The electrode exhibits a superior formate production rate (228.6 μmol h(-1)  cm(-2) ) at -1.36 VRHE without any considerable catalytic degradation over 18 h of operation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

CO2 Emission Reduction in Energy Sector

International Nuclear Information System (INIS)

Bole, A.; Sustersic, A.; Voncina, R.

2013-01-01

Due to human activities, concentrations of the greenhouse gases increase in the atmosphere much quicker than they naturally would. Today it is clear that climate change is the result of human activities. With the purpose of preventing, reducing and mitigating of climate change, the EU, whose member is also Slovenia, set ambitious goals. In order to keep rise of the global atmosphere temperature below 2 degrees of C, the European Council set an objective of reducing greenhouse gas emissions by 80 - 95 % by 2050 compared to 1990. It is important that every single individual is included in achieving of these goals. Certainly, the most important role is assumed by individual sectors especially Public Electricity and Heat Production sector as one of the greatest emitters of the greenhouse gases. As a possible solution of radical reduction of the greenhouse gases emission from mentioned sector Carbon Capture and Storage (CCS) technology is implemented. In the article the range of CO 2 reduction possibilities, technology demands and environmental side effects of CCS technology are described. Evaluation of CCS implementation possibilities in Slovenia is also included.(author)

Thermogravimetric and Magnetic Studies of the Oxidation and Reduction Reaction of SmCoO3 to Nanostructured Sm2O3 and Co

Science.gov (United States)

Kelly, Brian; Cichocki, Ronald; Poirier, Gerald; Unruh, Karl

The SmCoO3 to nanostructured Sm2O3 and Co oxidation and reduction reaction has been studied by thermogravimetric analysis (TGA) measurements in forming gas (FG) and inert N2 atmospheres, x-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The TGA measurements showed two clearly resolvable reduction processes when heating in FG, from the initial SmCoO3 phase through an intermediate nanostructured mixture of Sm2O3 and CoO when heated to 330°C for several minutes, and then the conversion of CoO to metallic Co when heated above 500°C. These phases were confirmed by XRD and VSM. Similar measurements in N2 yielded little mass change below 900°C and coupled reduction processes at higher temperatures. Isoconversional measurements of the CoO to Co reduction reaction in FG yielded activation energies above 2eV/atom in the nanostructured system. This value is several times larger than those reported in the literature or obtained by similar measurements of bulk mixtures of Sm2O3 and CoO, suggesting the nanostructuring was the source of the large increase in activation energy.

Strength Reduction of Coal Pillar after CO2 Sequestration in Abandoned Coal Mines

Directory of Open Access Journals (Sweden)

Qiuhao Du

2017-02-01

Full Text Available CO2 geosequestration is currently considered to be the most effective and economical method to dispose of artificial greenhouse gases. There are a large number of coal mines that will be scrapped, and some of them are located in deep formations in China. CO2 storage in abandoned coal mines will be a potential option for greenhouse gas disposal. However, CO2 trapping in deep coal pillars would induce swelling effects of coal matrix. Adsorption-induced swelling not only modifies the volume and permeability of coal mass, but also causes the basic physical and mechanical properties changing, such as elastic modulus and Poisson ratio. It eventually results in some reduction in pillar strength. Based on the fractional swelling as a function of time and different loading pressure steps, the relationship between volumetric stress and adsorption pressure increment is acquired. Eventually, this paper presents a theory model to analyze the pillar strength reduction after CO2 adsorption. The model provides a method to quantitatively describe the interrelation of volumetric strain, swelling stress, and mechanical strength reduction after gas adsorption under the condition of step-by-step pressure loading and the non-Langmuir isothermal model. The model might have a significantly important implication for predicting the swelling stress and mechanical behaviors of coal pillars during CO2 sequestration in abandoned coal mines.

Controlled electropolymerisation of a carbazole-functionalised iron porphyrin electrocatalyst for CO2 reduction

DEFF Research Database (Denmark)

Hu, Xinming; Salmi, Zakaria; Lillethorup, Mie

2016-01-01

Using a one-step electropolymerisation procedure, CO2 absorbing microporous carbazole-functionalised films of iron porphyrins are prepared in a controlled manner. The electrocatalytic reduction of CO2 for these films is investigated to elucidate their efficiency and the origin of their ultimate...

The Catalytic Bias of 2-Oxoacid:ferredoxin Oxidoreductase in CO_2: evolution and reduction through a ferredoxin-mediated electrocatalytic assay

International Nuclear Information System (INIS)

Li, Bin; Elliott, Sean J.

2016-01-01

Enzymes from the 2-oxoacid: ferredoxin oxidoreductase (OFOR) family engage in both CO_2 evolution and reduction in nature, depending on their physiological roles. Two enzymes and their redox partner ferredoxins (Fds) from Hydrogenobacter thermophilus and Desulfovibrio africanus were examined to investigate the basis of the catalytic bias. The Fd1 from H. thermophilus demonstrated a potential of ∼ −485 mV at room temperature, the lowest for known single [4Fe-4S] cluster Fds. It suggests a low potential electron donor may be the key factor in overcoming the large thermodynamic barrier of CO_2 reduction. The Fd-mediated electrocatalytic experiments further demonstrated the impact of Fd’s potential on the direction of the OFOR reaction: as OFOR enzymes could essentially catalyze both CO_2 evolution and reduction in vitro, the difference in their physiological roles is associated with the reduction potential of the redox partner Fd. The electrocatalytic assay could study both CO_2 evolution and reduction in one setup and is a good tool to probe Fds’ reactivity that arise from their reduction potentials.

CO2 emissions and reduction potential in China's chemical industry

International Nuclear Information System (INIS)

Zhu, Bing; Zhou, Wenji; Hu, Shanying; Li, Qiang; Griffy-Brown, Charla; Jin, Yong

2010-01-01

GHG (Increasing greenhouse gas) emissions in China imposes enormous pressure on China's government and society. The increasing GHG trend is primarily driven by the fast expansion of high energy-intensive sectors including the chemical industry. This study investigates energy consumption and CO 2 emissions in the processes of chemical production in China through calculating the amounts of CO 2 emissions and estimating the reduction potential in the near future. The research is based on a two-level perspective which treats the entire industry as Level one and six key sub-sectors as Level two, including coal-based ammonia, calcium carbide, caustic soda, coal-based methanol, sodium carbonate, and yellow phosphorus. These two levels are used in order to address the complexity caused by the fact that there are more than 40 thousand chemical products in this industry and the performance levels of the technologies employed are extremely uneven. Three scenarios with different technological improvements are defined to estimate the emissions of the six sub-sectors and analyze the implied reduction potential in the near future. The results highlight the pivotal role that regulation and policy administration could play in controlling the CO 2 emissions by promoting average technology performances in this industry.

Enhanced photocatalytic CO2 reduction to CH4 over separated dual co-catalysts Au and RuO2

Science.gov (United States)

Dong, Chunyang; Hu, Songchang; Xing, Mingyang; Zhang, Jinlong

2018-04-01

A spatially separated, dual co-catalyst photocatalytic system was constructed by the stepwise introduction of RuO2 and Au nanoparticles (NPs) at the internal and external surfaces of a three dimensional, hierarchically ordered TiO2-SiO2 (HTSO) framework (the final photocatalyst was denoted as Au/HRTSO). Characterization by HR-TEM, EDS-mapping, XRD and XPS confirmed the existence and spatially separated locations of Au and RuO2. In CO2 photocatalytic reduction (CO2PR), Au/HRTSO (0.8%) shows the optimal performance in both the activity and selectivity towards CH4; the CH4 yield is almost twice that of the singular Au/HTSO or HRTSO (0.8%, weight percentage of RuO2) counterparts. Generally, Au NPs at the external surface act as electron trapping agents and RuO2 NPs at the inner surface act as hole collectors. This advanced spatial configuration could promote charge separation and transfer efficiency, leading to enhanced CO2PR performance in both the yield and selectivity toward CH4 under simulated solar light irradiation.

Radiolytic reduction of nifurtimose by CO2-· free radicals

International Nuclear Information System (INIS)

Filali-Mouhim, A.; Champion, B.; Jore, D.; Ferradini, C.; Hickel, B.

1991-01-01

Nifurtimox is an antiparasitic drug often used in the treatment of the Chagas disease. Its therapeutic action seems to involve its monoelectronic reduction leading to a reduced radical capable of providing superoxide anion by reaction with oxygen. The oxidation reduction mechanisms involved in this action have been studied by steady state and pulse radiolysis methods. This study is devoted to the monoelectronic exchanges observed in the absence of air, the reducing radicals being the CO 2 - · anions [fr

Economic and game-theoretical analysis of CO2 reduction agreements

International Nuclear Information System (INIS)

Tahvonen, O.

1994-01-01

The possibility of climate change and suggestions to stabilize CO 2 emissions have led to several different fields of research in resource and environmental economics. These include: 1. Studies on country specific and global greenhouse gas abatement costs. 2. Studies on global and country specific adaptation costs. 3. Game-theoretical analysis of greenhouse gas reduction agreements. 4. Studies on the relationship between CO 2 accumulation and natural resource utilization. 5. Models of climate change and intertemporal efficiency and equity. 6. Studies on emissions taxes and emissions permit markets for greenhouse gas abatement. The aim of this project is to contribute to the economic literature in fields 3, and 4

Selective Reduction of CO2 to CH4 by Tandem Hydrosilylation with Mixed Al/B Catalysts

KAUST Repository

Chen, Jiawei

2016-04-04

This contribution reports the first example of highly selective reduction of CO2 into CH4 via tandem hydrosilylation with mixed main-group organo-Lewis acid (LA) catalysts [Al(C6F5)3 + B(C6F5)3] {[Al] + [B]}. As shown by this comprehensive experimental and computational study, in this unique tandem catalytic process, [Al] effectively mediates the first step of the overall reduction cycle, namely the fixation of CO2 into HCOOSiEt3 (1) via the LA-mediated C=O activation, while [B] is incapable of promoting the same transformation. On the other hand, [B] is shown to be an excellent catalyst for the subsequent reduction steps 2–4, namely the hydrosilylation of the more basic intermediates [1 to H2C(OSiEt3)2 (2) to H3COSiEt3 (3) and finally to CH4] through the frustrated-Lewis-pair (FLP)-type Si–H activation. Hence, with the required combination of [Al] and [B], a highly selective hydrosilylative reduction of CO2 system has been developed, achieving high CH4 production yield up to 94%. The remarkably different catalytic behaviors between [Al] and [B] are attributed to the higher overall Lewis acidity of [Al] derived from two conflicting factors (electronic and steric effects), which renders the higher tendency of [Al] to form stable [Al]–substrate (intermediate) adducts with CO2 as well as subsequent intermediates 1, 2 and 3. Overall, the roles of [Al] and [B] are not only complementary but also synergistic in the total reduction of CO2, which render both [Al]-mediated first reduction step and [B]-mediated subsequent steps catalytic.

Selective Reduction of CO2 to CH4 by Tandem Hydrosilylation with Mixed Al/B Catalysts

KAUST Repository

Chen, Jiawei; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y.-X.

2016-01-01

This contribution reports the first example of highly selective reduction of CO2 into CH4 via tandem hydrosilylation with mixed main-group organo-Lewis acid (LA) catalysts [Al(C6F5)3 + B(C6F5)3] {[Al] + [B]}. As shown by this comprehensive experimental and computational study, in this unique tandem catalytic process, [Al] effectively mediates the first step of the overall reduction cycle, namely the fixation of CO2 into HCOOSiEt3 (1) via the LA-mediated C=O activation, while [B] is incapable of promoting the same transformation. On the other hand, [B] is shown to be an excellent catalyst for the subsequent reduction steps 2–4, namely the hydrosilylation of the more basic intermediates [1 to H2C(OSiEt3)2 (2) to H3COSiEt3 (3) and finally to CH4] through the frustrated-Lewis-pair (FLP)-type Si–H activation. Hence, with the required combination of [Al] and [B], a highly selective hydrosilylative reduction of CO2 system has been developed, achieving high CH4 production yield up to 94%. The remarkably different catalytic behaviors between [Al] and [B] are attributed to the higher overall Lewis acidity of [Al] derived from two conflicting factors (electronic and steric effects), which renders the higher tendency of [Al] to form stable [Al]–substrate (intermediate) adducts with CO2 as well as subsequent intermediates 1, 2 and 3. Overall, the roles of [Al] and [B] are not only complementary but also synergistic in the total reduction of CO2, which render both [Al]-mediated first reduction step and [B]-mediated subsequent steps catalytic.

Investigation of the charge-transfer in photo-excited nanoparticles for CO2 reduction in non-aqueous media

Directory of Open Access Journals (Sweden)

Dimitrijević Nada M.

2013-01-01

Full Text Available Photoinduced charge separation in TiO2 and Cu2O semiconductor nanoparticles was examined using Electron Paramagnetic Resonance spectroscopy in order to get insight into the photocatalytic reduction of CO2 in nonaqueous media. For dissolution/grafting of CO2 we have used carboxy-PEG4-amine, and as a solvent poly(ethylene glycol 200. We have found that, in this system, reduction of CO2 starts at potential of -0.5 V vs Ag/AgCl, which is significantly more positive than the potential for electrochemical reduction of CO2 in most organic solvents and water (-2.0 V vs. Ag/AgCl. The electron transfer from excited nanoparticles to CO2 is governed both by thermodynamic and kinetic parameters, namely by the redox potential of conduction band electrons and adsorption/binding of CO2 on the surface of nanoparticles.

Storage of Renewable Energy by Reduction of CO2 with Hydrogen.

Science.gov (United States)

Züttel, Andreas; Mauron, Philippe; Kato, Shunsuke; Callini, Elsa; Holzer, Marco; Huang, Jianmei

2015-01-01

The main difference between the past energy economy during the industrialization period which was mainly based on mining of fossil fuels, e.g. coal, oil and methane and the future energy economy based on renewable energy is the requirement for storage of the energy fluxes. Renewable energy, except biomass, appears in time- and location-dependent energy fluxes as heat or electricity upon conversion. Storage and transport of energy requires a high energy density and has to be realized in a closed materials cycle. The hydrogen cycle, i.e. production of hydrogen from water by renewable energy, storage and use of hydrogen in fuel cells, combustion engines or turbines, is a closed cycle. However, the hydrogen density in a storage system is limited to 20 mass% and 150 kg/m(3) which limits the energy density to about half of the energy density in fossil fuels. Introducing CO(2) into the cycle and storing hydrogen by the reduction of CO(2) to hydrocarbons allows renewable energy to be converted into synthetic fuels with the same energy density as fossil fuels. The resulting cycle is a closed cycle (CO(2) neutral) if CO(2) is extracted from the atmosphere. Today's technology allows CO(2) to be reduced either by the Sabatier reaction to methane, by the reversed water gas shift reaction to CO and further reduction of CO by the Fischer-Tropsch synthesis (FTS) to hydrocarbons or over methanol to gasoline. The overall process can only be realized on a very large scale, because the large number of by-products of FTS requires the use of a refinery. Therefore, a well-controlled reaction to a specific product is required for the efficient conversion of renewable energy (electricity) into an easy to store liquid hydrocarbon (fuel). In order to realize a closed hydrocarbon cycle the two major challenges are to extract CO(2) from the atmosphere close to the thermodynamic limit and to reduce CO(2) with hydrogen in a controlled reaction to a specific hydrocarbon. Nanomaterials with

Atmospheric stabilization of CO2 emissions: Near-term reductions and absolute versus intensity-based targets

International Nuclear Information System (INIS)

Timilsina, Govinda R.

2008-01-01

This study analyzes CO 2 emissions reduction targets for various countries and geopolitical regions by the year 2030 to stabilize atmospheric concentrations of CO 2 at 450 ppm (550 ppm including non-CO 2 greenhouse gases) level. It also determines CO 2 intensity cuts that would be required in those countries and regions if the emission reductions were to be achieved through intensity-based targets without curtailing their expected economic growth. Considering that the stabilization of CO 2 concentrations at 450 ppm requires the global trend of CO 2 emissions to be reversed before 2030, this study develops two scenarios: reversing the global CO 2 trend in (i) 2020 and (ii) 2025. The study shows that global CO 2 emissions would be limited at 42 percent above 1990 level in 2030 if the increasing trend of global CO 2 emissions were to be reversed by 2020. If reversing the trend is delayed by 5 years, global CO 2 emissions in 2030 would be 52 percent higher than the 1990 level. The study also finds that to achieve these targets while maintaining expected economic growth, the global average CO 2 intensity would require a 68 percent drop from the 1990 level or a 60 percent drop from the 2004 level by 2030

Co-benefits from CO{sub 2}-emission reduction measurements in Shanxi, China - a first assessment

Energy Technology Data Exchange (ETDEWEB)

Aunan, Kristin; Fang, Jinghua; Li, Guanghai; Seip, Hans Martin; Vennemo, Haakon

2000-05-01

The largest local and regional air pollution problems are usually found in countries without emission reduction obligations in the Kyoto protocol. Thus, in many Chinese cities the concentrations of SO{sub 2} and particulates in the air by far exceed the WHO air quality guidelines. This report analyses a set of CO{sub 2}-reducing abatement options related to coal consumption in Shanxi, China. The costs and potential for abatement are investigated for different economic sectors and the entailed emission reductions are estimated in terms of CO{sub 2}, SO{sub 2} and particles. The present population-weighted exposure level for particles and SO{sub 2} is estimated and the reduced population exposure resulting from the abatement measures is assessed. Exposure-response functions from Chinese and international epidemiology are used to indicate the health effects of applying the measures. An economic evaluation of the reduced health effect is made by applying unit prices of health impacts based on the damage cost approach. The present agricultural crop loss due to enhanced levels of surface ozone are estimated. It is found that the CO{sub 2}-reducing abatement options in Shanxi are profitable in a socioeconomic sense. But there is a certain lack of synergy between the options with respect to their effectiveness in meeting local, regional and global environmental concerns.

Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

KAUST Repository

Min, Shixiong

2016-06-23

While recent reports have demonstrated that oxide-derived Cu-based electrodes exhibit high selectivity for CO2 reduction at low overpotential, the low catalytic current density (<2 mA/cm2 at -0.45 V vs. RHE) still largely limits its applications for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open frameworks, the resulting Cu foam electrodes prepared at higher temperatures exhibit enhanced electrochemically active surface area and distinct surface structures. In particular, the Cu foam electrode prepared at 500 °C exhibits an extremely high geometric current density of ~9.4 mA/cm2 in CO2-satrurated 0.1 M KHCO3 aqueous solution and achieving ~39% CO and ~23% HCOOH Faradaic efficiencies at -0.45 V vs. RHE. The high activity and significant selectivity enhancement are attributable to the formation of abundant grain-boundary supported active sites and preferable (100) and (111) facets as a result of reconstruction of Cu surface facets. This work demonstrates that the structural integration of Cu foam with open 3D frameworks and the favorable surface structures is a promising strategy to develop an advanced Cu electrocatalyst that can operate at high current density and low overpotential for CO2 reduction.

Soil CO2 efflux in loblolly pine (Pinus taeda L.) plantations on the virginia Piedmond and South Carolina coastal plain over a rotation-length chronosequence

Science.gov (United States)

Christopher M. Gough; John R. Seiler; P. Eric Wiseman; Christopher A. Maier

2005-01-01

We measured soil surface CO2 efflux (Fx) in loblolly pine stands (Pinus taeda L.) located on the Virginia Piedmont (VA) and South Carolina Coastal Plain (SC) in efforts to assess the impact climate, productivity, and cultural practices have on Fs in the managed loblolly pine...

Electrodeposition of nano-sized bismuth on copper foil as electrocatalyst for reduction of CO{sub 2} to formate

Energy Technology Data Exchange (ETDEWEB)

Lv, Weixin; Zhou, Jing; Bei, Jingjing [School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China); Zhang, Rui, E-mail: zhangrui@ycit.cn [School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China); Wang, Lei [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People’s Republic of China, Heilongjiang University, Harbin, 150080 (China); Xu, Qi [School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China); Wang, Wei, E-mail: wangw@ycit.edu.cn [School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China)

2017-01-30

Highlights: • Bi/Cu electrode was prepared by depositing nano-sized Bi catalyst on Cu foil. • The Bi/Cu electrode can reduce CO{sub 2} to formate with a low overpotential. • The energy efficiency for reduction of CO{sub 2} to formate can reach to 50%. • A Tafel slope of 128 mV decade{sup −1} was observed for producing formate. - Abstract: Electrochemical reduction of carbon dioxide (CO{sub 2}) to formate is energetically inefficient because high overpotential is required for reduction of CO{sub 2} to formate on most traditional catalysts. In this paper, a novel nano-sized Bi-based electrocatalyst deposited on a Cu foil has been synthesized, which can be used as a cathode for electrochemical reduction of CO{sub 2} to formate with a low overpotential (0.69 V) and a high selectivity (91.3%). The electrocatalyst can show excellent catalytic performance toward reduction of CO{sub 2} which can probably be attributed to the nano-sized structure and the surface oxide layer. The energy efficiency for reduction of CO{sub 2} to formate can reach to 50% when an Ir{sub x}Sn{sub y}Ru{sub z}O{sub 2}/Ti electrode is used as anode, it is one of the highest values found in the literatures and very practicable for sustainable fuel synthesis.

Alternative photocatalysts to TiO{sub 2} for the photocatalytic reduction of CO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Nikokavoura, Aspasia; Trapalis, Christos, E-mail: c.trapalis@inn.demokritos.gr

2017-01-01

Highlights: • Non TiO{sub 2} containing photocatalysts are intensively studied for CO{sub 2} reduction. • The inorganic and carbon based semiconductors are appropriate for redox reactions. • ZIFs and carbonaceous hybrids exhibited outstanding photocatalytic efficiency. • Highly active photocatalysts for CO{sub 2} conversion to useful materials are needed. - Abstract: The increased concentration of CO{sub 2} in the atmosphere, originating from the burning of fossil fuels in stationary and mobile sources, is referred as the “Anthropogenic Greenhouse Effect” and constitutes a major environmental concern. The scientific community is highly concerned about the resulting enhancement of the mean atmospheric temperature, so a vast diversity of methods has been applied. Thermochemical, electrochemical, photocatalytic, photoelectrochemical processes, as well as combination of solar electricity generation and water splitting processes have been performed in order to lower the CO{sub 2} atmospheric levels. Photocatalytic methods are environmental friendly and succeed in reducing the atmospheric CO{sub 2} concentration and producing fuels or/and useful organic compounds at the same time. The most common photocatalysts for the CO{sub 2} reduction are the inorganic, the carbon based semiconductors and the hybrids based on semiconductors, which combine stability, low cost and appropriate structure in order to accomplish redox reactions. In this review, inorganic semiconductors such as single-metal oxide, mixed-metal oxides, metal oxide composites, layered double hydroxides (LDHs), salt composites, carbon based semiconductors such as graphene based composites, CNT composites, g-C{sub 3}N{sub 4} composites and hybrid organic-inorganic materials (ZIFs) were studied. TiO{sub 2} and Ti based photocatalysts are extensively studied and therefore in this review they are not mentioned.

Optimal production resource reallocation for CO2 emissions reduction in manufacturing sectors

OpenAIRE

Fujii, Hidemichi; Managi, Shunsuke

2015-01-01

To mitigate the effects of climate change, countries worldwide are advancing technologies to reduce greenhouse gas emissions. This paper proposes and measures optimal production resource reallocation using data envelopment analysis. This research attempts to clarify the effect of optimal production resource reallocation on CO2 emissions reduction, focusing on regional and industrial characteristics. We use finance, energy, and CO2 emissions data from 13 industrial sectors in 39 countries from...

Carbon-supported cubic CoSe2 catalysts for oxygen reduction reaction in alkaline medium

International Nuclear Information System (INIS)

Feng Yongjun; Alonso-Vante, Nicolas

2012-01-01

Highlights: ► Cubic CoSe 2 a non-precious metal electrocatalyst for oxygen reduction in KOH. ► The catalyst shows four-electron transfer pathway in overall reaction. ► Catalyst has higher methanol tolerance than commercial Pt/C catalyst. - Abstract: A Carbon-supported CoSe 2 nanocatalyst has been developed as an alternative non-precious metal electrocatalyst for oxygen reduction reaction (ORR) in alkaline medium. The catalyst was prepared via a surfactant-free route and its electrocatalytic activity for the ORR has been investigated in detail in 0.1 M KOH electrolyte at 25 °C using rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) techniques. The prepared catalyst showed promising catalytic activity towards ORR in a four-electron transfer pathway and higher tolerance to methanol compared to commercial Pt/C catalyst in 0.1 M KOH. To some extent, the increase of CoSe 2 loading on the electrode favors a faster reduction of H 2 O 2 intermediate to H 2 O.

Reduction of CO2 emissions during cement clinker burning; part 1 = Ein Beitrag zur Reduzierung der CO2-Emissionen beim Zementklinkerbrand; Teil 1

NARCIS (Netherlands)

Vogel, S.; Kolditz, K.; Bellmann, F.; Ott-Reinhardt, D.; Kralisch, D.

2013-01-01

The aim of the research project entitled "New technology in cement production for reducing CO2 emissions" sponsored by the German Federal Environmental Foundation was to lower the CO2 emissions during clinker burning. A possible reduction, relative to an industrial example, of up to 21 % in the

CO{sub 2} reduction cost for bio-diesel, Danish produced bio-diesel based on rape seed; CO{sub 2} reduktionsomkostninger ved biodiesel. Dansk produceret biodiesel pae raps

Energy Technology Data Exchange (ETDEWEB)

Carlsen, Kirsten; Kjellingbro, M; Mogensen, Martin Frank; Kohl, M

2006-12-15

Bio-diesel based on rape seed (RME, Rape Methyl Esther), often referred to as first generation bio-diesel, is a renewable fuel with CO{sub 2} reduction potential. Mixed with conventional diesel it can be used directly in existing diesel engines. The EU target for the use of bio-fuels in the transport sector was 2 % by 2005 and is 5.75 % by 2010. In Denmark, the use of bio-fuels in the transport sector is not viewed as a cost-effective CO{sub 2} reduction measure. This conclusion concerning the cost-effectiveness of bio-fuels was partly based on calculations of the CO2 reduction cost for Danish-produced RME made by the Danish Energy Authority in 2003. At that time the cost was estimated at 360 DKK/tonne CO{sub 2}. Since then some of the assumptions behind the calculations have changed. The overall objective of this report is to update the Danish Energy Authority's study from 2003, taking into account revised assumptions. The report also attempts to examine the uncertainties associated with the calculations by including extended sensitivity analyses. The report draws the following conclusions: 1) The CO{sub 2} reduction cost for Danish produced RME is estimated at 860 DKK/tonne CO{sub 2}, which is significantly higher than the result obtained by the Danish Energy Authority in 2003. 2) The difference from the Danish Energy Authority's original calculations is principally due to a higher rape seed price based on the market price on rape seed. 3) The uncertainty in both estimates is substantial, and there is about 15 % probability of the reduction costs being lower than the target of 180 DKK/tonne CO2 set by the government. (au)

CO{sub 2} reduction cost for bio-diesel, Danish produced bio-diesel based on rape seed; CO{sub 2} reduktionsomkostninger ved biodiesel. Dansk produceret biodiesel pae raps

Energy Technology Data Exchange (ETDEWEB)

Carlsen, Kirsten; Kjellingbro, M.; Mogensen, Martin Frank; Kohl, M.

2006-12-15

Bio-diesel based on rape seed (RME, Rape Methyl Esther), often referred to as first generation bio-diesel, is a renewable fuel with CO{sub 2} reduction potential. Mixed with conventional diesel it can be used directly in existing diesel engines. The EU target for the use of bio-fuels in the transport sector was 2 % by 2005 and is 5.75 % by 2010. In Denmark, the use of bio-fuels in the transport sector is not viewed as a cost-effective CO{sub 2} reduction measure. This conclusion concerning the cost-effectiveness of bio-fuels was partly based on calculations of the CO2 reduction cost for Danish-produced RME made by the Danish Energy Authority in 2003. At that time the cost was estimated at 360 DKK/tonne CO{sub 2}. Since then some of the assumptions behind the calculations have changed. The overall objective of this report is to update the Danish Energy Authority's study from 2003, taking into account revised assumptions. The report also attempts to examine the uncertainties associated with the calculations by including extended sensitivity analyses. The report draws the following conclusions: 1) The CO{sub 2} reduction cost for Danish produced RME is estimated at 860 DKK/tonne CO{sub 2}, which is significantly higher than the result obtained by the Danish Energy Authority in 2003. 2) The difference from the Danish Energy Authority's original calculations is principally due to a higher rape seed price based on the market price on rape seed. 3) The uncertainty in both estimates is substantial, and there is about 15 % probability of the reduction costs being lower than the target of 180 DKK/tonne CO2 set by the government. (au)

A supply chain optimization framework for CO₂ emission reduction: Case of the Netherlands

OpenAIRE

Kalyanarengan Ravi, Narayen; Zondervan, Edwin; Van Sint Annaland, Martin; Fransoo, Jan C.; Grievink, J.

2016-01-01

A major challenge for the industrial deployment of a CO2 emission reduction methodology is to reduce the overall cost and the integration of all the nodes in the supply chain for CO2 emission reduction. In this work, we develop a mixed integer linear optimization model that selects appropriate sources, capture process, transportation network and CO2 storage sites and optimize for a minimum overall cost. Initially, we screen the sources and storage options available in the Netherlands at diffe...

Efficient TEA CO2 laser based coating removal system

CSIR Research Space (South Africa)

Prinsloo, FJ

2007-04-01

Full Text Available stream_source_info Prinsloo_2007.pdf.txt stream_content_type text/plain stream_size 11617 Content-Encoding UTF-8 stream_name Prinsloo_2007.pdf.txt Content-Type text/plain; charset=UTF-8 Efficient TEA CO2 laser based... by keeping energy density below the damage threshold. The advantage of a pulsed TEA CO2 laser system is that a laser frequency and temporal profile can be chosen to maximize paint removal and concurrently minimize substrate damage. To achieve...

Heterologous Expression of the Clostridium carboxidivorans CO Dehydrogenase Alone or Together with the Acetyl Coenzyme A Synthase Enables both Reduction of CO2 and Oxidation of CO by Clostridium acetobutylicum.

Science.gov (United States)

Carlson, Ellinor D; Papoutsakis, Eleftherios T

2017-08-15

With recent advances in synthetic biology, CO 2 could be utilized as a carbon feedstock by native or engineered organisms, assuming the availability of electrons. Two key enzymes used in autotrophic CO 2 fixation are the CO dehydrogenase (CODH) and acetyl coenzyme A (acetyl-CoA) synthase (ACS), which form a bifunctional heterotetrameric complex. The CODH/ACS complex can reversibly catalyze CO 2 to CO, effectively enabling a biological water-gas shift reaction at ambient temperatures and pressures. The CODH/ACS complex is part of the Wood-Ljungdahl pathway (WLP) used by acetogens to fix CO 2 , and it has been well characterized in native hosts. So far, only a few recombinant CODH/ACS complexes have been expressed in heterologous hosts, none of which demonstrated in vivo CO 2 reduction. Here, functional expression of the Clostridium carboxidivorans CODH/ACS complex is demonstrated in the solventogen Clostridium acetobutylicum , which was engineered to express CODH alone or together with the ACS. Both strains exhibited CO 2 reduction and CO oxidation activities. The CODH reactions were interrogated using isotopic labeling, thus verifying that CO was a direct product of CO 2 reduction, and vice versa. CODH apparently uses a native C. acetobutylicum ferredoxin as an electron carrier for CO 2 reduction. Heterologous CODH activity depended on actively growing cells and required the addition of nickel, which is inserted into CODH without the need to express the native Ni insertase protein. Increasing CO concentrations in the gas phase inhibited CODH activity and altered the metabolite profile of the CODH-expressing cells. This work provides the foundation for engineering a complete and functional WLP in nonnative host organisms. IMPORTANCE Functional expression of CO dehydrogenase (CODH) from Clostridium carboxidivorans was demonstrated in C. acetobutylicum , which is natively incapable of CO 2 fixation. The expression of CODH, alone or together with the C. carboxidivorans

A Co3O4-CDots-C3N4 three component electrocatalyst design concept for efficient and tunable CO2 reduction to syngas.

Science.gov (United States)

Guo, Sijie; Zhao, Siqi; Wu, Xiuqin; Li, Hao; Zhou, Yunjie; Zhu, Cheng; Yang, Nianjun; Jiang, Xin; Gao, Jin; Bai, Liang; Liu, Yang; Lifshitz, Yeshayahu; Lee, Shuit-Tong; Kang, Zhenhui

2017-11-28

Syngas, a CO and H 2 mixture mostly generated from non-renewable fossil fuels, is an essential feedstock for production of liquid fuels. Electrochemical reduction of CO 2 and H + /H 2 O is an alternative renewable route to produce syngas. Here we introduce the concept of coupling a hydrogen evolution reaction (HER) catalyst with a CDots/C 3 N 4 composite (a CO 2 reduction catalyst) to achieve a cheap, stable, selective and efficient route for tunable syngas production. Co 3 O 4 , MoS 2 , Au and Pt serve as the HER component. The Co 3 O 4 -CDots-C 3 N 4 electrocatalyst is found to be the most efficient among the combinations studied. The H 2 /CO ratio of the produced syngas is tunable from 0.07:1 to 4:1 by controlling the potential. This catalyst is highly stable for syngas generation (over 100 h) with no other products besides CO and H 2 . Insight into the mechanisms balancing between CO 2 reduction and H 2 evolution when applying the HER-CDots-C 3 N 4 catalyst concept is provided.

Membraneless laminar flow cell for electrocatalytic CO2 reduction with liquid product separation

International Nuclear Information System (INIS)

Monroe, Morgan M; Lobaccaro, Peter; Lum, Yanwei; Ager, Joel W

2017-01-01

The production of liquid fuel products via electrochemical reduction of CO 2 is a potential path to produce sustainable fuels. However, to be practical, a separation strategy is required to isolate the fuel-containing electrolyte produced at the cathode from the anode and also prevent the oxidation products (i.e. O 2 ) from reaching the cathode. Ion-conducting membranes have been applied in CO 2 reduction reactors to achieve this separation, but they represent an efficiency loss and can be permeable to some product species. An alternative membraneless approach is developed here to maintain product separation through the use of a laminar flow cell. Computational modelling shows that near-unity separation efficiencies are possible at current densities achievable now with metal cathodes via optimization of the spacing between the electrodes and the electrolyte flow rate. Laminar flow reactor prototypes were fabricated with a range of channel widths by 3D printing. CO 2 reduction to formic acid on Sn electrodes was used as the liquid product forming reaction, and the separation efficiency for the dissolved product was evaluated with high performance liquid chromatography. Trends in product separation efficiency with channel width and flow rate were in qualitative agreement with the model, but the separation efficiency was lower, with a maximum value of 90% achieved. (paper)

Transition paths towards CO2 emission reduction in the steel industry

NARCIS (Netherlands)

Daniëls, Berend Wilhelm

2002-01-01

Radiative forcing, better known as the Greenhouse Effect, is probably the major 21st century environmental problem. Its probable cause is the anthropogenic emission of greenhouse gases, especially CO2. The Kyoto agreement enforces considerable reductions of the GHG emissions in 2010, with 6 to 8% of

Initial Reduction of CO2 on Pd-, Ru-, and Cu-Doped CeO2(111) Surfaces: Effects of Surface Modification on Catalytic Activity and Selectivity.

Science.gov (United States)

Guo, Chen; Wei, Shuxian; Zhou, Sainan; Zhang, Tian; Wang, Zhaojie; Ng, Siu-Pang; Lu, Xiaoqing; Wu, Chi-Man Lawrence; Guo, Wenyue

2017-08-09

Surface modification by metal doping is an effective treatment technique for improving surface properties for CO 2 reduction. Herein, the effects of doped Pd, Ru, and Cu on the adsorption, activation, and reduction selectivity of CO 2 on CeO 2 (111) were investigated by periodic density functional theory. The doped metals distorted the configuration of a perfect CeO 2 (111) by weakening the adjacent Ce-O bond strength, and Pd doping was beneficial for generating a highly active O vacancy. The analyses of adsorption energy, charge density difference, and density of states confirmed that the doped metals were conducive for enhancing CO 2 adsorption, especially for Cu/CeO 2 (111). The initial reductive dissociation CO 2 → CO* + O* on metal-doped CeO 2 (111) followed the sequence of Cu- > perfect > Pd- > Ru-doped CeO 2 (111); the reductive hydrogenation CO 2 + H → COOH* followed the sequence of Cu- > perfect > Ru- > Pd-doped CeO 2 (111), in which the most competitive route on Cu/CeO 2 (111) was exothermic by 0.52 eV with an energy barrier of 0.16 eV; the reductive hydrogenation CO 2 + H → HCOO* followed the sequence of Ru- > perfect > Pd-doped CeO 2 (111). Energy barrier decomposition analyses were performed to identify the governing factors of bond activation and scission along the initial CO 2 reduction routes. Results of this study provided deep insights into the effect of surface modification on the initial reduction mechanisms of CO 2 on metal-doped CeO 2 (111) surfaces.

Estimation and reduction of CO2 emissions from crude oil distillation units

International Nuclear Information System (INIS)

Gadalla, M.; Olujic, Z.; Jobson, M.; Smith, R.

2006-01-01

Distillation systems are energy-intensive processes, and consequently contribute significantly to the greenhouse gases emissions (e.g. carbon dioxide (CO 2 ). A simple model for the estimation of CO 2 emissions associated with operation of heat-integrated distillation systems as encountered in refineries is introduced. In conjunction with a shortcut distillation model, this model has been used to optimize the process conditions of an existing crude oil atmospheric tower unit aiming at minimization of CO 2 emissions. Simulation results indicate that the total CO 2 emissions of the existing crude oil unit can be cut down by 22%, just by changing the process conditions accordingly, and that the gain in this respect can be doubled by integrating a gas turbine. In addition, emissions reduction is accompanied by substantial profit increase due to utility saving and/or export

The electrochemical selective reduction of NO using CoSe2@CNTs hybrid.

Science.gov (United States)

Liu, Hui; Xiang, Kaisong; Yang, Bentao; Xie, Xiaofeng; Wang, Dongli; Zhang, Cong; Liu, Zhilou; Yang, Shu; Liu, Cao; Zou, Jianping; Chai, Liyuan

2017-06-01

Converting the NO from gaseous pollutant into NH 4 + through electrocatalytical reduction using cost-effective materials holds great promise for pollutant purifying and resources recycling. In this work, we developed a highly selective and stable catalyst CoSe 2 nanoparticle hybridized with carbon nanotubes (CoSe 2 @CNTs). The CoSe 2 @CNTs hybrid catalysts performed an extraordinary high selectivity for NH 4 + formation in NO electroreduction with minimal N 2 O production and H 2 evolution. The specific spatial structure of CoSe 2 is conductive to the predominant formation of N-H bond between the N from adsorbed NO and H and inhibition of N-N formation from adjacent adsorbed NO. It was also the first time to convert the coordinated NO into NH 4 + using non-noble metal catalysis. Moreover, the original concept of employing CoSe 2 as eletrocatalyst for NO hydrogenation presented in this work can broaden horizons and provide new dimensions in the design of new highly efficient catalysts for NH 4 + synthesis in aqueous solution.

The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 - venting sediments (Milos Island, Greece).

Science.gov (United States)

Bayraktarov, Elisa; Price, Roy E; Ferdelman, Timothy G; Finster, Kai

2013-01-01

Microbial sulfate reduction (SR) is a dominant process of organic matter mineralization in sulfate-rich anoxic environments at neutral pH. Recent studies have demonstrated SR in low pH environments, but investigations on the microbial activity at variable pH and CO2 partial pressure are still lacking. In this study, the effect of pH and pCO2 on microbial activity was investigated by incubation experiments with radioactive (35)S targeting SR in sediments from the shallow-sea hydrothermal vent system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main site of fluid discharge. Adjacent to the vent site (T ~40-75°C, pH ~5), maximal sulfate reduction rates (SRR) were observed between pH 5 and 6. SR in hydrothermally influenced sediments decreased at neutral pH. Sediments unaffected by hydrothermal venting (T ~26°C, pH ~8) expressed the highest SRR between pH 6 and 7. Further experiments investigating the effect of pCO2 on SR revealed a steep decrease in activity when the partial pressure increased from 2 to 3 bar. Findings suggest that sulfate reducing microbial communities associated with hydrothermal vent system are adapted to low pH and high CO2, while communities at control sites required a higher pH for optimal activity.

Effects of composition of the micro porous layer and the substrate on performance in the electrochemical reduction of CO2 to CO

Science.gov (United States)

Kim, Byoungsu; Hillman, Febrian; Ariyoshi, Miho; Fujikawa, Shigenori; Kenis, Paul J. A.

2016-04-01

With the development of better catalysts, mass transport limitations are becoming a challenge to high throughput electrochemical reduction of CO2 to CO. In contrast to optimization of electrodes for fuel cells, optimization of gas diffusion electrodes (GDE) - consisting of a carbon fiber substrate (CFS), a micro porous layer (MPL), and a catalyst layer (CL) - for CO2 reduction has not received a lot of attention. Here, we studied the effect of the MPL and CFS composition on cathode performance in electroreduction of CO2 to CO. In a flow reactor, optimized GDEs exhibited a higher partial current density for CO production than Sigracet 35BC, a commercially available GDE. By performing electrochemical impedance spectroscopy in a CO2 flow reactor we determined that a loading of 20 wt% PTFE in the MPL resulted in the best performance. We also investigated the influence of the thickness and wet proof level of CFS with two different feeds, 100% CO2 and the mixture of 50% CO2 and N2, determining that thinner and lower wet proofing of the CFS yields better cathode performance than when using a thicker and higher wet proof level of CFS.

Modern digital plain-radiography of the whole spine in scoliosis patients. Dose reduction and quality criteria

International Nuclear Information System (INIS)

Kloth, Jost Karsten; Stiller, W.; Kauczor, H.U.; Weber, M.A.

2013-01-01

To reduce the radiation exposure of plain radiographs of the entire spine depending on specific indications, since these are frequently performed examinations of children and young adults with scoliosis and to determine objective quality control criteria to ensure accurate assessment. In this prospective randomized study 323 patients underwent plain-radiography of the entire spine with standard and 50 % reduced dose. In an experimental pilot-study this target-dose was determined using an Alderson-Phantom. The evaluation of the experimental radiographs, as well as, the randomized plain-radiographs was conducted using the following criteria: endplates (Cobb-angle), spinal process and pedicel (rotation), lateral margin of the vertebral body (lateral alignment), identification of C7 / S1 (perpendicular). Two radiologists evaluated these criteria using a score ranging from 1 (definitely assessable) to 4 (not assessable). If one single criteria was evaluated with a score of 3 or more points or more than 2 criteria with 2 points, the radiograph was scored as ''not assessable''. The statistical analysis was conducted as a non-inferiority-trial. Seven (2.4 %) of the 290 examined x-rays were scored as not assessable. There was no statistic inferiority between the examinations with standard or reduced dose, while singular assessment of the defined criteria was likewise dose-independent. Plain-radiography of the total spine in patients with scoliosis can be performed with a dose reduction of 50 % without a loss of validity. The obtained quality control criteria were clinically applicable. (orig.)

Electrochemical Reduction of CO2 on IrxRu(1–x)O2(110) Surfaces 

DEFF Research Database (Denmark)

Bhowmik, Arghya; Hansen, Heine Anton; Vegge, Tejs

2017-01-01

with oxygen-coordinated intermediates that can circumvent the limitations imposed by the scaling relations on metal catalysts. Here, we introduce an innovative concept of ligand effects in oxide catalysts. Both IrO2 and RuO2 binds OH* and other intermediates from the electrochemical reduction of CO2 (CO2RR......High overpotentials and low faradic efficiencies plague metal catalysts for direct conversion of CO2 to methanol and other liquid fuels. RuO2-based electrocatalysts have been observed to evolve methanol at low overpotentials, which has been attributed to an alternative reaction mechanism......) strongly, but the stable and miscible system IrxRu(1-x)O2 exhibits anomalous weaker binding energy in the presence of CO* spectators, because of Ru–Ir ligand effects. The weakened adsorbate binding leads to a very low CO2RR onset potential (methanol evolution at −0.2 V RHE). An Ir atom at the bridge site...

Alternative photocatalysts to TiO2 for the photocatalytic reduction of CO2

Science.gov (United States)

Nikokavoura, Aspasia; Trapalis, Christos

2017-01-01

The increased concentration of CO2 in the atmosphere, originating from the burning of fossil fuels in stationary and mobile sources, is referred as the "Anthropogenic Greenhouse Effect" and constitutes a major environmental concern. The scientific community is highly concerned about the resulting enhancement of the mean atmospheric temperature, so a vast diversity of methods has been applied. Thermochemical, electrochemical, photocatalytic, photoelectrochemical processes, as well as combination of solar electricity generation and water splitting processes have been performed in order to lower the CO2 atmospheric levels. Photocatalytic methods are environmental friendly and succeed in reducing the atmospheric CO2 concentration and producing fuels or/and useful organic compounds at the same time. The most common photocatalysts for the CO2 reduction are the inorganic, the carbon based semiconductors and the hybrids based on semiconductors, which combine stability, low cost and appropriate structure in order to accomplish redox reactions. In this review, inorganic semiconductors such as single-metal oxide, mixed-metal oxides, metal oxide composites, layered double hydroxides (LDHs), salt composites, carbon based semiconductors such as graphene based composites, CNT composites, g-C3N4 composites and hybrid organic-inorganic materials (ZIFs) were studied. TiO2 and Ti based photocatalysts are extensively studied and therefore in this review they are not mentioned.

Studies on CO2 removal and reduction. CO2 taisaku kenkyu no genjo

Energy Technology Data Exchange (ETDEWEB)

Shindo, Y [National Institute of Materials and Chemical Research, Tsukuba (Japan)

1993-02-01

This paper summarizes study trends mainly in CO2 fixing processes. Underground CO2 storage is a most promising method because it can fix a huge amount of CO2 and has low effects on ecological systems. Storing CO2 in ocean includes such methods as storing it in deep oceans; storing it in deep ocean beds; dissolving it into sea water; neutralizing it with calcium carbonates; and precipitating it as dry ice. Japan, disposing CO2 in these ways, may create international problems. Separation of CO2 may use a chemical absorption process as a superior method. Other processes discussed include a physical adsorption method and a membrane separation method. A useful method for CO2 fixation using marine organisms is fixation using coral reefs. This process will require an overall study including circulation of phosphorus and nitrogen. Marine organisms may include planktons and algae. CO2 fixation using land plants may be able to fix one trillion and 8 hundred billion tons of CO2 as converted to carbon. This process would require forest protection, prevention of desertification, and tree planting. Discussions are being given also on improving power generation cycles, recovering CO2 from automotive exhausts, and backfilling carbons into ground by means of photosynthesis. 23 refs., 7 figs., 1 tab.

Copper-Based Metal-Organic Porous Materials for CO2 Electrocatalytic Reduction to Alcohols.

Science.gov (United States)

Albo, Jonathan; Vallejo, Daniel; Beobide, Garikoitz; Castillo, Oscar; Castaño, Pedro; Irabien, Angel

2017-03-22

The electrocatalytic reduction of CO 2 has been investigated using four Cu-based metal-organic porous materials supported on gas diffusion electrodes, namely, (1) HKUST-1 metal-organic framework (MOF), [Cu 3 (μ 6 -C 9 H 3 O 6 ) 2 ] n ; (2) CuAdeAce MOF, [Cu 3 (μ 3 -C 5 H 4 N 5 ) 2 ] n ; (3) CuDTA mesoporous metal-organic aerogel (MOA), [Cu(μ-C 2 H 2 N 2 S 2 )] n ; and (4) CuZnDTA MOA, [Cu 0.6 Zn 0.4 (μ-C 2 H 2 N 2 S 2 )] n . The electrodes show relatively high surface areas, accessibilities, and exposure of the Cu catalytic centers as well as favorable electrocatalytic CO 2 reduction performance, that is, they have a high efficiency for the production of methanol and ethanol in the liquid phase. The maximum cumulative Faradaic efficiencies for CO 2 conversion at HKUST-1-, CuAdeAce-, CuDTA-, and CuZnDTA-based electrodes are 15.9, 1.2, 6, and 9.9 %, respectively, at a current density of 10 mA cm -2 , an electrolyte-flow/area ratio of 3 mL min cm -2 , and a gas-flow/area ratio of 20 mL min cm -2 . We can correlate these observations with the structural features of the electrodes. Furthermore, HKUST-1- and CuZnDTA-based electrodes show stable electrocatalytic performance for 17 and 12 h, respectively. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potential CO{sub 2} reduction by fuel substitution to generate electricity in Malaysia

Energy Technology Data Exchange (ETDEWEB)

Masjuki, H.H.; Mahlia, T.M.I.; Choudhury, I.A.; Saidur, R. [University of Malaysia, Kuala Lumpur (Malaysia). Dept. of Mechanical Engineers

2002-04-01

Because of changing fossil fuel prices, sources and environmental consciousness, Malaysian utilities have been forced to change the type of energy sources to generate electricity. This new policy of electricity generation companies will change fuel use gradually from 70% gas, 15% coal, 10% hydro and 5% petroleum in the year 2000 to 40% gas, 30% hydro, 29% coal and only 1% petroleum in the year of 2020. These changes tend to reduce CO{sub 2} emission. This study predicts the potential CO{sub 2} reduction due to these changes. The calculation is based on CO{sub 2} emission for unit electricity generated and the changing type of fuel percentages for electricity generation in Malaysia. The study found that the substitution will reduce CO{sub 2} emission from power plants in this country.

Scenario analysis on CO2 emissions reduction potential in China's iron and steel industry

International Nuclear Information System (INIS)

Wang Ke; Wang Can; Lu Xuedu; Chen Jining

2007-01-01

The international climate community has begun to assess a range of possible options for strengthening the international climate change effort after 2012. Analysis of the potential for sector-based emissions reduction and relevant mitigation options will provide the necessary background information for the debate. In order to assess the CO 2 abatement potential of China's steel industry, a model was developed using LEAP software to generate 3 different CO 2 emission scenarios for the industry from 2000 to 2030. The abatement potentials of different scenarios were compared, and their respective feasibilities were assessed according to the cost information. High priority abatement measures were then identified. The results show that the average CO 2 abatement per year in the Recent Policy scenario and in the New Policy scenario, compared with the reference scenario, are 51 and 107 million tons, respectively. The corresponding total incremental costs are 9.34 and 80.95 billion dollars. It is concluded that there is great potential for CO 2 abatement in China's steel industry. Adjusting the structure of the industry and technological advancement will play an important role in emissions reduction. Successful implementation of current sustainable development policies and measures will result in CO 2 abatement at a low cost. However, to achieve higher levels of abatement, the cost will increase dramatically. In the near future, specific energy conservation technologies such as dry coke quenching, exhaust gas and heat recovery equipment will be of great significance. However, taking a long term perspective, emissions reduction will rely more on the adjustment of production processes and the application of more modern large scale plants. Advanced blast furnace technology will inevitably play an important role

The limited role of aquifer heterogeneity on metal reduction in an Atlantic coastal plain determined by push-pull tests

International Nuclear Information System (INIS)

Mailloux, Brian J.; Devlin, Stephanie; Fuller, Mark E.; Onstott, T.C.; De Flaun, Mary F.; Choi, K.-H.; Green-Blum, Maria; Swift, Donald J.P.; McCarthy, John; Dong Hailiang

2007-01-01

Sixty push-pull experiments were conducted to determine the factors controlling Fe(III) and Mn(IV) reduction in a well-characterized, shallow, coastal plain aquifer near Oyster, VA, USA. The five multi-level samplers each equipped with 12 ports sampled a heterogeneous portion of the aquifer from 4.4 to 8m-bgs. Each multi-level sampler (MLS) was injected with groundwater that contained NO 3 - and Br - along with: (1) just groundwater (control treatment), (2) humics, (3) lactate (conducted twice) and (4) lactate plus humics. Microbially mediated Fe(III) reduction caused the aqueous Fe Tot concentrations to increase at every depth in the lactate treatment with significant increases within 1 day even while NO 3 - was present. Little change in the Fe Tot concentrations were observed in the control and humics treatment. Humics may have acted as an electron shuttle to increase Fe(III) reduction in the lactate plus humics treatment. The amount of Mn(IV) reduction was significantly lower than that of Fe(III) reduction. Geochemical modeling indicated that gas formation, sorption on reactive surfaces, and mineral precipitation were important processes and that Fe(III) and SO 4 2- reduction were co-occurring. Conditions were favorable for the precipitation of Fe-carbonates, Fe-sulfides and Fe-silicates. In the lactate treatment protist concentrations increased then decreased and planktonic cell concentrations steadily increased, whereas no change was observed in the control treatment. Correlations of Fe(III) reduction with physical and chemical heterogeneity were weak, probably as a result of the abundance of Fe(III) bearing minerals relative to electron donor abundance and that the push-pull test sampled a representative elemental volume that encompassed the microbial diversity within the aquifer. This work indicates that stimulating metal reduction in aquifer systems is a feasible method for remediating heterogeneous subsurface sites contaminated with metals and

Study on CO2 emission reduction using ENPEP in Korea

International Nuclear Information System (INIS)

Moon, K. H.; Kim, S. S.; Song, K. D.; Im, C. Y.

2003-01-01

ENPEP was used to analyze the role of nuclear power in mitigating carbon emission in power generation sector. In this study, base scenario reflects business as usual case in Korea. Additional two scenarios were established. One stands for fuel switch scenario, where nuclear power plants scheduled to be introduced after 2008 were assumed to be replaced by Coal Power Plant, the other one is established to see the impact of carbon tax. In this scenario carbon tax(50$/ton-C0 2 ) is imposed on coal power plants from 2008. It is resulted that fuel switch from nuclear to coal in power generation sector has a great effect on CO 2 emission, while carbon tax imposition makes a slight contribution to the reduction of CO 2 emission. These findings mean that the role of nuclear power in Korea is important in view of the GHG mitigation

The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 – venting sediments (Milos Island, Greece)

Science.gov (United States)

Bayraktarov, Elisa; Price, Roy E.; Ferdelman, Timothy G.; Finster, Kai

2013-01-01

Microbial sulfate reduction (SR) is a dominant process of organic matter mineralization in sulfate-rich anoxic environments at neutral pH. Recent studies have demonstrated SR in low pH environments, but investigations on the microbial activity at variable pH and CO2 partial pressure are still lacking. In this study, the effect of pH and pCO2 on microbial activity was investigated by incubation experiments with radioactive 35S targeting SR in sediments from the shallow-sea hydrothermal vent system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main site of fluid discharge. Adjacent to the vent site (T ~40–75°C, pH ~5), maximal sulfate reduction rates (SRR) were observed between pH 5 and 6. SR in hydrothermally influenced sediments decreased at neutral pH. Sediments unaffected by hydrothermal venting (T ~26°C, pH ~8) expressed the highest SRR between pH 6 and 7. Further experiments investigating the effect of pCO2 on SR revealed a steep decrease in activity when the partial pressure increased from 2 to 3 bar. Findings suggest that sulfate reducing microbial communities associated with hydrothermal vent system are adapted to low pH and high CO2, while communities at control sites required a higher pH for optimal activity. PMID:23658555

The effect of CO2, H2O and SO2 on the kinetics of NO reduction by CH4 over La2O3

International Nuclear Information System (INIS)

Toops, Todd J.; Walters, Arden B.; Vannice, M.A.

2002-01-01

The effect of CO 2 , H 2 O and SO 2 on the kinetics of NO reduction by CH 4 over unsupported La 2 O 3 has been examined between 773 and 973K in the presence of O 2 in the feed. La 2 O 3 can maintain a stable, high specific activity (mol/(sm 2 )) for NO reduction with high concentrations of CO 2 and H 2 O in the feed; however, either of these two products reversibly inhibits the activity by about one-half in the presence of excess O 2 . The catalyst is poisoned by SO 2 at these temperatures and an oxysulfate phase is formed, but partial regeneration can be achieved at 1023K. CO 2 in the feed causes the formation of lanthanum oxycarbonate, which reverts to La 2 O 3 when CO 2 is removed, but no bulk La oxyhydroxide is detected after quenching with H 2 O in the feed. The influence of CO 2 and H 2 O on kinetic behavior can be described by assuming they compete with reactants for adsorption on surface sites, including them in the site balance equation, and using the rate expression proposed previously for NO reduction by CH 4 in excess O 2 . With O 2 in the feed, integral conversions of CH 4 and O 2 frequently occurred due to the direct combustion of CH 4 by O 2 , although NO conversions remained differential; thus, an integral reactor model was chosen to analyze the data which utilized a recently determined rate equation for CH 4 combustion on La 2 O 3 in conjunction with a previously proposed model for NO reduction by CH 4 . The following rate expression described the rate of N 2 formation: N 2 T = ' NO P NO P CH 4 P O 2 0.5 / 1 + K NO P NO + K CH 4 P CH 4 + K O 2 0.5 P O 2 0.5 + K CO 2 P CO 2 + K H 2 O P H 2 O 2 . It gave a good fit to the experimental rate data for NO reduction, as well as providing enthalpies and entropies of adsorption obtained from the fitting parameters that demonstrated thermodynamic consistency and were similar to previous values. The heats of adsorption were altered somewhat when either CO 2 or H 2 O was added to the feed, and the following

Efficient Electrocatalytic Reduction of CO2 by Nitrogen-Doped Nanoporous Carbon/Carbon Nanotube Membranes - A Step Towards the Electrochemical CO2 Refinery

KAUST Repository

Wang, Hong; Jia, Jia; Song, Pengfei; Wang, Qiang; Li, Debao; Min, Shixiong; Qian, Chenxi; Wang, Lu; Li, Young Feng; Ma, Chun; Wu, Tao; Yuan, Jiayin; Antonietti, Markus; Ozin, Geoffrey A.

2017-01-01

The search for earth abundant, efficient and stable electrocatalysts that can enable the chemical reduction of CO2 to value-added chemicals and fuels at an industrially relevant scale, is a high priority for the development of a global network of renewable energy conversion and storage systems that can meaningfully impact greenhouse gas induced climate change. Here we introduce a straightforward, low cost, scalable and technologically relevant method to manufacture an all-carbon, electroactive, nitrogen-doped nanoporous carbon-carbon nanotube composite membrane. The membrane is demonstrated to function as a binder-free, high-performance electrode for the electrocatalytic reduction of CO2 to formate. The Faradaic efficiency for the production of formate is 81%. Furthermore, the robust structural and electrochemical properties of the membrane endow it with excellent long-term stability.

Efficient Electrocatalytic Reduction of CO2 by Nitrogen-Doped Nanoporous Carbon/Carbon Nanotube Membranes - A Step Towards the Electrochemical CO2 Refinery

KAUST Repository

Wang, Hong

2017-05-12

The search for earth abundant, efficient and stable electrocatalysts that can enable the chemical reduction of CO2 to value-added chemicals and fuels at an industrially relevant scale, is a high priority for the development of a global network of renewable energy conversion and storage systems that can meaningfully impact greenhouse gas induced climate change. Here we introduce a straightforward, low cost, scalable and technologically relevant method to manufacture an all-carbon, electroactive, nitrogen-doped nanoporous carbon-carbon nanotube composite membrane. The membrane is demonstrated to function as a binder-free, high-performance electrode for the electrocatalytic reduction of CO2 to formate. The Faradaic efficiency for the production of formate is 81%. Furthermore, the robust structural and electrochemical properties of the membrane endow it with excellent long-term stability.

Identifying Activity Descriptors for CO2 Electro-Reduction to Methanol on Rutile (110) Surfaces

DEFF Research Database (Denmark)

Bhowmik, Arghya; Hansen, Heine Anton; Vegge, Tejs

2015-01-01

Electrocatalytic reduction of CO2 to liquid fuels using energy from renewable sources has the potential to form the basis of a carbon neutral sustainable energy system, while integrating seamlessly in the established infrastructure1. Storing intermittent renewable energy in a chemical fuel...... towards electrocatalytic production of methanol. We would like to acknowledge the Lundbeck Foundation for financial support of this work. References: 1. Lewis, N. S. & Nocera, D. G. Powering the planet: chemical challenges in solar energy utilization. Proc. Natl. Acad. Sci. U. S. A.103,15729–35 (2006......., Ali, I., Jansen, M. & Omanovic, S. Electrochemical reduction of CO 2 in an aqueous electrolyte employing an iridium/ruthenium-oxide electrode. Can. J. Chem. Eng. (2014). doi:10.1002/cjce.22110 6. Nørskov, J. K. et al. Origin of the Overpotential for Oxygen Reduction at a Fuel-Cell Cathode. J. Phys...

Reduction of CO2 emissions by reduction of paper use for publication applications

Energy Technology Data Exchange (ETDEWEB)

Van den Reek, J.A.

1999-10-01

The main research question of this study is as follows: What is the technical potential for reducing paper use in the field of publication applications in Western Europe within a time frame of 10-20 years, and what will the consequences for CO2 emissions be? To answer this central question we have defined the next four subquestions, all related to Western Europe: (1) How were the historical trends for the consumption figures of publication papers?; (2) What will be the expected publication paper consumption the next 10-20 years based on the historical trends, and what will be the influence on the related CO2 emissions?; (3) What technical opportunities do we see to reduce the future paper consumption trend for publication applications and what will be the individual and cumulative technical potential of these innovations?; (4) Does implementation of the technical opportunities lead to a significant dematerialization effect? Chapter 2 describes the chosen research method. In Chapter 3 we will introduce and define the paper types studied. Furthermore, Chapter 3 describes the detailed division of publication papers we have used in this study and the relationship with pulp and papermaking. After reading this chapter it has to be clear which paper production methods and paper types are (per ton) responsible for how much CO2 emissions. To get an overall-impression of the relevance of certain papers for CO2 emission numbers it is important to have insight into the historical consumption patterns of publication papers. Chapter 4 pays attention to these consumption patterns. Chapter 5 describes the most important trend factors that may influence future paper consumption patterns and in Chapter 6 this is translated into three possible consumption growth scenarios. The first and second growth scenarios are only based on extrapolations from historical figures, the third scenario is based on some of the most significant potential reduction measures. Furthermore, Chapter 6 gives

CO_2 emissions reduction of Chinese light manufacturing industries: A novel RAM-based global Malmquist–Luenberger productivity index

International Nuclear Information System (INIS)

Emrouznejad, Ali; Yang, Guo-liang

2016-01-01

Climate change has become one of the most challenging issues facing the world. Chinese government has realized the importance of energy conservation and prevention of the climate changes for sustainable development of China's economy and set targets for CO_2 emissions reduction in China. In China industry contributes 84.2% of the total CO_2 emissions, especially manufacturing industries. Data envelopment analysis (DEA) and Malmquist productivity (MP) index are the widely used mathematical techniques to address the relative efficiency and productivity of a group of homogenous decision making units, e.g. industries or countries. However, in many real applications, especially those related to energy efficiency, there are often undesirable outputs, e.g. the pollutions, waste and CO_2 emissions, which are produced inevitably with desirable outputs in the production. This paper introduces a novel Malmquist–Luenberger productivity (MLP) index based on directional distance function (DDF) to address the issue of productivity evolution of DMUs in the presence of undesirable outputs. The new RAM (Range-adjusted measure)-based global MLP index has been applied to evaluate CO_2 emissions reduction in Chinese light manufacturing industries. Recommendations for policy makers have been discussed. - Highlights: •CO_2 emissions reduction in Chinese light manufacturing industries are measured. •A novel RAM based Malmquist–Luenberger productivity index has been developed. •Recommendation to policy makers for reducing CO_2 reduction in China are given.

Assessment of Alternative Scenarios for CO2 Reduction Potential in the Residential Building Sector

Directory of Open Access Journals (Sweden)

Young-Sun Jeong

2017-03-01

Full Text Available The South Korean government announced its goals of reducing the country’s CO2 emissions by up to 30% below the business as usual (BAU projections by 2020 in 2009 and 37% below BAU projections by 2030 in 2015. This paper explores the potential energy savings and reduction in CO2 emissions offered by residential building energy efficiency policies and plans in South Korea. The current and future energy consumption and CO2 emissions in the residential building were estimated using an energy–environment model from 2010 to 2030. The business as usual scenario is based on the energy consumption characteristic of residential buildings using the trends related to socio-economic prospects and the number of dwellings. The alternative scenarios took into account energy efficiency for new residential buildings (scenario I, refurbishment of existing residential buildings (scenario II, use of highly efficient boilers (scenario III, and use of a solar thermal energy system (scenario IV. The results show that energy consumption in the residential building sector will increase by 33% between 2007 and 2030 in the BAU scenario. Maximum reduction in CO2 emissions in the residential building sector of South Korea was observed by 2030 in scenario I. In each alternative scenario analysis, CO2 emissions were 12.9% lower than in the business as usual scenario by the year 2030.

Twin defects engineered Pd cocatalyst on C3N4 nanosheets for enhanced photocatalytic performance in CO2 reduction reaction

Science.gov (United States)

Lang, Qingqing; Hu, Wenli; Zhou, Penghui; Huang, Tianlong; Zhong, Shuxian; Yang, Lining; Chen, Jianrong; Bai, Song

2017-12-01

Photocatalytic conversion of CO2 to value-added chemicals, a potential route to addressing the depletion of fossil fuels and anthropogenic climate change, is greatly limited by the low-efficient semiconductor photocatalyst. The integration of cocatalyst with light-harvesting semiconductor is a promising approach to enhancing the photocatalytic performance in CO2 reduction reaction. The enhancement is greatly determined by the catalytic active sites on the surface of cocatalyst. Herein, we demonstrate that the photocatalytic performance in the CO2 reduction reaction is greatly promoted by twin defects engineered Pd cocatalyst. In this work, Pd nanoicosahedrons with twin defects were in situ grown on C3N4 nanosheets, which effectively improve the photocatalytic performance in reduction of CO2 to CO and CH4 in comparison with Pd nanotetrahedrons without twin defects. It is proposed that the twin boundary (TB) terminations on the surface of Pd cocatalysts are highly catalytic active sites for CO2 reduction reaction. Based on the proposed mechanism, the photocatalytic activity and selectivity in CO2 reduction were further advanced through reducing the size of Pd icosahedral cocatalyst resulted from the increased surface density of TB terminations. The defect engineering on the surface of cocatalyst represents a novel route in realizing high-performance photocatalytic applications.

Densely Packed, Ultra Small SnO Nanoparticles for Enhanced Activity and Selectivity in Electrochemical CO2 Reduction.

Science.gov (United States)

Gu, Jun; Héroguel, Florent; Luterbacher, Jeremy; Hu, Xile

2018-03-05

Controlling the selectivity in electrochemical CO 2 reduction is an unsolved challenge. While tin (Sn) has emerged as a promising non-precious catalyst for CO 2 electroreduction, most Sn-based catalysts produce formate as the major product, which is less desirable than CO in terms of separation and further use. Tin monoxide (SnO) nanoparticles supported on carbon black were synthesized and assembled and their application in CO 2 reduction was studied. Remarkably high selectivity and partial current densities for CO formation were obtained using these SnO nanoparticles compared to other Sn catalysts. The high activity is attributed to the ultra-small size of the nanoparticles (2.6 nm), while the high selectivity is attributed to a local pH effect arising from the dense packing of nanoparticles in the conductive carbon black matrix. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficiency potentials of heat pumps with combined heat and power. For maximum reduction of CO2 emissions and for electricity generation from fossil fuels with CO2 reduction in Switzerland

International Nuclear Information System (INIS)

Rognon, F.

2005-06-01

This comprehensive report for the Swiss Federal Office of Energy (SFOE) takes a look at how the efficiency potential of heat pumps together with combined heat and power systems can help provide a maximum reduction of CO 2 emissions and provide electricity generation from fossil fuel in Switzerland together with reductions in CO 2 emissions. In Switzerland, approximately 80% of the low-temperature heat required for space-heating and for the heating-up of hot water is produced by burning combustibles. Around a million gas and oil boilers were in use in Switzerland in 2000, and these accounted for approximately half the country's 41.1 million tonnes of CO 2 emissions. The authors state that there is a more efficient solution with lower CO 2 emissions: the heat pump. With the enormous potential of our environment it would be possible to replace half the total number of boilers in use today with heat pumps. This would be equivalent to 90 PJ p.a. of useful heat, or 500,000 systems. The power source for heat pumps should come from the substitution of electric heating systems (electric resistor-based systems) and from the replacement of boilers. This should be done by using combined heat and power systems with full heat utilisation. This means, according to the authors, that the entire required power source can be provided without the need to construct new electricity production plants. The paper examines and discusses the theoretical, technical, market and realisable potentials

Analyses on Cost Reduction and CO2 Mitigation by Penetration of Fuel Cells to Residential Houses

Science.gov (United States)

Aki, Hirohisa; Yamamoto, Shigeo; Kondoh, Junji; Murata, Akinobu; Ishii, Itaru; Maeda, Tetsuhiko

This paper presents analyses on the penetration of polymer electrolyte fuel cells (PEFC) into a group of 10 residential houses and its effects of CO2 emission mitigation and consumers’ cost reduction in next 30 years. The price is considered to be reduced as the penetration progress which is expected to begin in near future. An experimental curve is assumed to express the decrease of the price. Installation of energy interchange systems which involve electricity, gas and hydrogen between a house which has a FC and contiguous houses is assumed to utilize both electricity and heat more efficiently, and to avoid start-stop operation of fuel processor (reformer) as much as possible. A multi-objective model which considers CO2 mitigation and consumers’ cost reduction is constructed and provided a Pareto optimum solution. A solution which simultaneously realizes both CO2 mitigation and consumers’ cost reduction appeared in the Pareto optimum solution. Strategies to reduce CO2 emission and consumers’ cost are suggested from the results of the analyses. The analyses also revealed that the energy interchange systems are effective especially in the early stage of the penetration.

Marginal CO2 reduction cost in ENERGY 2000 development. A socio-economic evaluation of the marginal cost for the alternative reduction methods

International Nuclear Information System (INIS)

Maeng, H.

1995-01-01

The official Danish environmental plan involves a reduction of CO 2 within the next 30-50 years. This report describes the analysis of socio-economic cost/consequences of marginal CO 2 reduction by means of various technical solution models. Calculations by means of the special program subroutine SAMFOKO are based on energy balance in annual, monthly, daily and hourly scale. Heat and power savings as well as the development of decentralized power plants are considered in the supply model. Socio-economic consequences in form of charges and cost are discussed. (EG)

Strategic research on CO2 emission reduction for China. Application of MARKAL to China energy system

International Nuclear Information System (INIS)

Wang Yongping

1995-09-01

MARKAL was applied to the energy system for analyzing the CO 2 emission reduction in China over the time period from 1990 to 2050. First the Chinese Reference Energy System (CRES) was established based on the framework of MARKAL model. The following conclusions can be drawn from this study. When shifting from scenario LH (low useful energy demand and high import fuel prices) to HL (high demand and low prices), another 33 EJ of primary energy will be consumed and another 2.31 billion tons of CO 2 will be emitted in 2050. Detailed analyses on the disaggregation of CO 2 emissions by Kaya Formula show. The energy intensity (primary energy/GDP) decreases much faster in scenario HL, but the higher growth rate of GDP per capita is the overwhelming factor that results in higher CO 2 emission per capita in the baseline case of scenario HL in comparison with LH. When the carbon taxes are imposed on CO 2 emissions, the residential sector will make the biggest contribution to CO 2 emission abatement from a long-term point of view. However, it's difficult to stabilize CO 2 emission per capita before 2030 in both scenarios even with heavy carbon taxes. When nuclear moratorium occurs, more 560 million tons of CO 2 will be emitted to the atmosphere in 2050 under the same CO 2 tax regime. From the analysis of value flow, CO 2 emission reduction depends largely on new or advanced technologies particularly in the field of electricity generation. The competent technologies switch to those CO 2 less-emitting technologies when surcharging CO 2 emissions. Nuclear power shows significant potential in saving fossil energy resources and reducing CO 2 emissions. (J.P.N.)

The costs of reducing the excess CO{sub 2} emissions. Reduction potential and costs in certain sector; Hvad koster det at reducere CO{sup 2}-mankoen? - Reduktionspotentiale og omkostninger i udvalgte sektorer

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-07-01

The report presents the results from the project 'The costs of reducing the excess CO{sub 2} emissions - reduction potential and costs in certain sectors'. The aim of the project has been to elucidate the full extent of the reduction potentials and the costs for certain CO{sub 2} reducing initiatives, which are not included in the present projections of the excess CO{sub 2} emissions. The initiatives included in this report are: Accumulation of methane from Danish disposal facilities; Accumulation of methane from disposal facilities in Russia; Reduction in the use of industrial greenhouse gases; Aquifer disposal of CO{sub 2} in the underground; Offshore CO{sub 2} disposal in oil fields in the North Sea. Furthermore, the report presents a general evaluation of the potential of methane accumulation from wastewater treatment. (ba)

Free energy landscape of electrocatalytic CO2 reduction to CO on aqueous FeN4 center embedded graphene studied by ab initio molecular dynamics simulations

Science.gov (United States)

Sheng, Tian; Sun, Shi-Gang

2017-11-01

Experiments have found that the porphyrin-like FeN4 site in Fe-N-C materials is highly efficient for the electrochemical reduction of CO2 into CO. In this work, we investigated the reduction mechanisms on FeN4 embedded graphene layer catalyst with some explicit water molecules by combining the constrained ab initio molecular dynamics simulations and thermodynamic integrations. The reaction free energy and electron transfer in each elementary step were identified. The initial CO2 activation was identified to go through the first electron transfer to form adsorbed CO2- anion and the CO desorption was the rate limiting step in the overall catalytic cycle.

Smart Transportation CO2 Emission Reduction Strategies

Science.gov (United States)

Tarulescu, S.; Tarulescu, R.; Soica, A.; Leahu, C. I.

2017-10-01

Transport represents the sector with the fastest growing greenhouse gas emissions around the world. The main global objective is to reduce energy usage and associated greenhouse gas emissions from the transportation sector. For this study it was analyzed the road transportation system from Brasov Metropolitan area. The study was made for the transportation route that connects Ghimbav city to the main surrounding objectives. In this study ware considered four optimization measures: vehicle fleet renewal; building the detour belt for the city; road increasing the average travel speed; making bicycle lanes; and implementing an urban public transport system for Ghimbav. For each measure it was used a mathematical model to calculate the energy consumption and carbon emissions from the road transportation sector. After all four measures was analyzed is calculated the general energy consumption and CO2 reduction if this are applied from year 2017 to 2020.

Productivity and CO2 exchange of Great Plains ecoregions. I. Shortgrass steppe: Flux tower estimates

Science.gov (United States)

Gilmanov, Tagir G.; Morgan, Jack A.; Hanan, Niall P.; Wylie, Bruce K.; Rajan, Nithya; Smith, David P.; Howard, Daniel M.

2017-01-01

The shortgrass steppe (SGS) occupies the southwestern part of the Great Plains. Half of the land is cultivated, but significant areas remain under natural vegetation. Despite previous studies of the SGS carbon cycle, not all aspects have been completely addressed, including gross productivity, ecosystem respiration, and ecophysiological parameters. Our analysis of 1998 − 2007 flux tower measurements at five Bowen ratio–energy balance (BREB) and three eddy covariance (EC) sites characterized seasonal and interannual variability of gross photosynthesis and ecosystem respiration. Identification of the nonrectangular hyperbolic equation for the diurnal CO2 exchange, with vapor pressure deficit (VPD) limitation and exponential temperature response, quantified quantum yield α, photosynthetic capacity Amax, and respiration rate rd with variation ranges (19 \\production from − 900 to + 700 g CO2 m− 2 yr− 1, indicating that SGS may switch from a sink to a source depending on weather. Comparison of the 2004 − 2006 measurements at two BREB and two parallel EC flux towers located at comparable SGS sites showed moderately higher photosynthesis, lower respiration, and higher net production at the BREB than EC sites. However, the difference was not related only to methodologies, as the normalized difference vegetation index at the BREB sites was higher than at the EC sites. Overall magnitudes and seasonal patterns at the BREB and the EC sites during the 3-yr period were similar, with trajectories within the ± 1.5 standard deviation around the mean of the four sites and mostly reflecting the effects of meteorology.

Environmental benefits from CO2 reduction, due to modal replacement: Case study on light rail vehicle in Brasilia City

Energy Technology Data Exchange (ETDEWEB)

Silva Costa, P.H. da; Alves Teixeira, L.M.; Cardoso Pinheiro, J.; Serra Arruda, F.; Mendonça Brasil, A.C.

2016-07-01

This work aims to measure the reduction of Carbon Dioxide (CO2) emissions in atmosphere by replacing the modal urban bus by Light Rail Vehicle (VLT). In order to accomplish this objective, a case study in Brasilia, Federal District, in the stretch of VLT which passes on Via W-3 South was conducted. The Theory of Externalities that discusses the right to ownership of private and public goods and responsibilities about the positive and negative externalities caused by the agents and individuals of society was used to support the analyses. It was used the Top-Down method, which allowed the calculation the direct emissions of CO2. The values obtained on the reduction of CO2 emissions were converted into values of carbon credits as a way to economically measure such reductions. The results showed a significant reduction in CO2 emissions per year and consequent environmental benefit. (Author)

Realizing CO2 emission reduction through industrial symbiosis: A cement production case study for Kawasaki

OpenAIRE

Hashimoto, Shizuka; Fujita, Tsuyoshi; Geng, Yong; Nagasawa, Emiri

2010-01-01

This article is one effort to examine the present and potential performances of CO2 emission reduction though industrial symbiosis by employing a case study approach and life cycle CO2 analysis for alternative industrial symbiosis scenarios. As one of the first and the best-known eco-town projects, Kawasaki Eco-town was chosen as a case study area. First, the current industrial symbiosis practices in this area are introduced. To evaluate the potential of reducing the total CO2 emission throug...

Simulation of Degraded Properties of 2D plain Woven C/SiC Composites under Preloading Oxidation Atmosphere

Science.gov (United States)

Chen, Xihui; Sun, Zhigang; Sun, Jianfen; Song, Yingdong

2017-12-01

In this paper, a numerical model which incorporates the oxidation damage model and the finite element model of 2D plain woven composites is presented for simulation of the oxidation behaviors of 2D plain woven C/SiC composite under preloading oxidation atmosphere. The equal proportional reduction method is firstly proposed to calculate the residual moduli and strength of unidirectional C/SiC composite. The multi-scale method is developed to simulate the residual elastic moduli and strength of 2D plain woven C/SiC composite. The multi-scale method is able to accurately predict the residual elastic modulus and strength of the composite. Besides, the simulated residual elastic moduli and strength of 2D plain woven C/SiC composites under preloading oxidation atmosphere show good agreements with experimental results. Furthermore, the preload, oxidation time, temperature and fiber volume fractions of the composite are investigated to show their influences upon the residual elastic modulus and strength of 2D plain woven C/SiC composites.

Novel, Regenerable Microlith Catalytic Reactor for CO2 Reduction via Bosch Process, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Precision Combustion, Inc. (PCI) proposes to develop an extremely compact, lightweight and regenerable MicrolithREG catalytic CO2 reduction reactor, capable of...

Uncertainty-averse TRANSCO planning for accommodating renewable energy in CO2 reduction environment

DEFF Research Database (Denmark)

Zhang, Chunyu; Ding, Yi; Wang, Qi

2015-01-01

, demand-side variations, market price volatility, and transmission configuration. Three objectives, i.e. social CO2 reduction benefit, energy purchase and network expansion cost and power delivery profit, are optimized simultaneously by a developed two-phase multi-objective particle swarm optimization......The concern of the environment and energy sustainability requests a crucial target of CO2 abatement and results in a relatively high penetration of renewable energy generation in the transmission system. For maintaining system reliability and security, the transmission company (TRANSCO) has to make...

Rhenium Complexes Based on 2-Pyridyl-1,2,3-triazole Ligands: A New Class of CO2 Reduction Catalysts.

Science.gov (United States)

Ching, H Y Vincent; Wang, Xia; He, Menglan; Perujo Holland, Noemi; Guillot, Régis; Slim, Cyrine; Griveau, Sophie; Bertrand, Hélène C; Policar, Clotilde; Bedioui, Fethi; Fontecave, Marc

2017-03-06

A series of [Re(N^N)(CO) 3 (X)] (N^N = diimine and X = halide) complexes based on 4-(2-pyridyl)-1,2,3-triazole (pyta) and 1-(2-pyridyl)-1,2,3-triazole (tapy) diimine ligands have been prepared and electrochemically characterized. The first ligand-based reduction process is shown to be highly sensitive to the nature of the isomer as well as to the substituents on the pyridyl ring, with the peak potential changing by up to 700 mV. The abilities of this class of complexes to catalyze the electroreduction and photoreduction of CO 2 were assessed for the first time. It is found that only Re pyta complexes that have a first reduction wave with a peak potential at ca. -1.7 V vs SCE are active, producing CO as the major product, together with small amounts of H 2 and formic acid. The catalytic wave that is observed in the CVs is enhanced by the addition of water or trifluoroethanol as a proton source. Long-term controlled potential electrolysis experiments gave total Faradaic yield close to 100%. In particular, functionalization of the triazolyl ring with a 2,4,6-tri-tert-butylphenyl group provided the catalyst with a remarkable stability.

Achieving CO2 reductions in Colombia: Effects of carbon taxes and abatement targets

International Nuclear Information System (INIS)

Calderón, Silvia; Alvarez, Andrés Camilo; Loboguerrero, Ana María; Arango, Santiago; Calvin, Katherine; Kober, Tom; Daenzer, Kathryn; Fisher-Vanden, Karen

2016-01-01

In this paper we investigate CO 2 emission scenarios for Colombia and the effects of implementing carbon taxes and abatement targets on the energy system. By comparing baseline and policy scenario results from two integrated assessment partial equilibrium models TIAM-ECN and GCAM and two general equilibrium models Phoenix and MEG4C, we provide an indication of future developments and dynamics in the Colombian energy system. Currently, the carbon intensity of the energy system in Colombia is low compared to other countries in Latin America. However, this trend may change given the projected rapid growth of the economy and the potential increase in the use of carbon-based technologies. Climate policy in Colombia is under development and has yet to consider economic instruments such as taxes and abatement targets. This paper shows how taxes or abatement targets can achieve significant CO 2 reductions in Colombia. Though abatement may be achieved through different pathways, taxes and targets promote the entry of cleaner energy sources into the market and reduce final energy demand through energy efficiency improvements and other demand-side responses. The electric power sector plays an important role in achieving CO 2 emission reductions in Colombia, through the increase of hydropower, the introduction of wind technologies, and the deployment of biomass, coal and natural gas with CO 2 capture and storage (CCS). Uncertainty over the prevailing mitigation pathway reinforces the importance of climate policy to guide sectors toward low-carbon technologies. This paper also assesses the economy-wide implications of mitigation policies such as potential losses in GDP and consumption. An assessment of the legal, institutional, social and environmental barriers to economy-wide mitigation policies is critical yet beyond the scope of this paper. - Highlights: • Four energy and economy-wide models under carbon mitigation scenarios are compared. • Baseline results show that CO

H2-assisted CO2 thermochemical reduction on La0.9Ca0.1FeO3-δ membranes: a kinetics study

KAUST Repository

Wu, Xiao-Yu; Ghoniem, Ahmed F.

2017-01-01

Kinetics data for CO2 thermochemical reduction in an isothermal membrane reactor is required to identify the rate-limiting steps. Here, we report a detailed reaction kinetics study on this process supported by an La0.9Ca0.1FeO3-δ (LCF-91) membrane. The dependence of CO2 reduction rate on various operating conditions is examined such as CO2 concentration on the feed side, fuel concentrations on the sweep side and temperatures. CO2 reduction rate is proportional to the oxygen flux across the membrane, and the measured maximum fluxes are 0.191 and 0.164 μmol cm-2 s-1 with 9.5% H2 and 11.6% CO on the sweep side at 990oC, respectively. Fuel is used to maintain the chemical potential gradient across the membrane and CO is used by construction to derive the surface reaction kinetics. This membrane also exhibits stable performances for 106 hours. A resistance-network model is developed to describe the oxygen transport process and the kinetics data are parameterized using the experimental values. The model shows a transition of the rate limiting step between the surface reactions on the feed side and the sweep side depending on the operating conditions.

H2-assisted CO2 thermochemical reduction on La0.9Ca0.1FeO3-δ membranes: a kinetics study

KAUST Repository

Wu, Xiao-Yu

2017-11-04

Kinetics data for CO2 thermochemical reduction in an isothermal membrane reactor is required to identify the rate-limiting steps. Here, we report a detailed reaction kinetics study on this process supported by an La0.9Ca0.1FeO3-δ (LCF-91) membrane. The dependence of CO2 reduction rate on various operating conditions is examined such as CO2 concentration on the feed side, fuel concentrations on the sweep side and temperatures. CO2 reduction rate is proportional to the oxygen flux across the membrane, and the measured maximum fluxes are 0.191 and 0.164 μmol cm-2 s-1 with 9.5% H2 and 11.6% CO on the sweep side at 990oC, respectively. Fuel is used to maintain the chemical potential gradient across the membrane and CO is used by construction to derive the surface reaction kinetics. This membrane also exhibits stable performances for 106 hours. A resistance-network model is developed to describe the oxygen transport process and the kinetics data are parameterized using the experimental values. The model shows a transition of the rate limiting step between the surface reactions on the feed side and the sweep side depending on the operating conditions.

A CsPbBr3 Perovskite Quantum Dot/Graphene Oxide Composite for Photocatalytic CO2 Reduction.

Science.gov (United States)

Xu, Yang-Fan; Yang, Mu-Zi; Chen, Bai-Xue; Wang, Xu-Dong; Chen, Hong-Yan; Kuang, Dai-Bin; Su, Cheng-Yong

2017-04-26

Halide perovskite quantum dots (QDs), primarily regarded as optoelectronic materials for LED and photovoltaic devices, have not been applied for photochemical conversion (e.g., water splitting or CO 2 reduction) applications because of their insufficient stability in the presence of moisture or polar solvents. Herein, we report the use of CsPbBr 3 QDs as novel photocatalysts to convert CO 2 into solar fuels in nonaqueous media. Under AM 1.5G simulated illumination, the CsPbBr 3 QDs steadily generated and injected electrons into CO 2 , catalyzing CO 2 reduction at a rate of 23.7 μmol/g h with a selectivity over 99.3%. Additionally, through the construction of a CsPbBr 3 QD/graphene oxide (CsPbBr 3 QD/GO) composite, the rate of electron consumption increased 25.5% because of improved electron extraction and transport. This study is anticipated to provide new opportunities to utilize halide perovskite QD materials in photocatalytic applications.

Searching for electrolytes and electrodes for CO₂ reduction below 300 °C

DEFF Research Database (Denmark)

Vico, Federica

Electrochemical CO2 reduction research is driven by the desire to reduce reliance on fossil fuels and lower greenhouse gas emissions. The conversion of CO2 into fuels and chemicals using energy derived from a renewable source, such as wind or solar, could replace the use of fossil fuels...... practical application for carbon dioxide reduction at high pressure. K-doped BaZr1-xYxO3-δ was successfully synthesized by hydrothermal technique, but the conductivity recorded in high pH2O and at 240 °C was too low (3 · 10-5 S/cm) to be considered as a suitable electrolyte. A literature survey showed...... and temperatures. A foam based CO2 conversion cell with gas diffusion electrodes and a ceramic porous structure in which the liquid electrolyte is immobilized by capillary forces was developed and tested up to 20 bar and to a maximum temperature of 50 °C. Potassium carbonate was selected as aqueous electrolyte...

Abatement of CO{sub 2} emissions: IFP's solutions; Reduction des emissions de CO{sub 2}: les solutions IFP

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-07-01

In a context of increasing energy consumption and world economic growth, the fight against greenhouse gases has become a major technological challenge for the coming years. The capture and sequestration of CO{sub 2} in the underground is a promising solution in terms of environmental impact, especially in places and sectors characterized by a strong concentration of CO{sub 2} emissions (power generation plants, big industries). However, such a solution requires important R and D efforts to reduce the costs and warrant the long-term reliability of the storage. The French institute of petroleum (IFP) will play an important role in the implementation of the geological sequestration. This press kit comprises 7 documents: a press release from November 4, 2003; a press conference with a series of slides presenting the stakes, solutions and actions proposed by the IFP in collaboration with several foreign partners (CO{sub 2} capture, storage in depleted hydrocarbon deposits, saline aquifers or abandoned coal seams, storage potential, reduction of costs); a summary of the stakes and solutions for CO{sub 2} sequestration in deep underground; a similar document presented at the Panorama 2003 colloquium; the CO{sub 2} constraint in France and in Europe (international consensus on climatic change, Kyoto protocol, European directive about tradable carbon permits, voluntary commitment of companies in the fight against greenhouse effects (AERES)); the European project Castor (CO{sub 2} from capture to storage); and the IFP brochure 'innovating for a sustainable development in the energy domain'. (J.S.)

Temperature-programmed reaction of CO2 reduction in the presence of hydrogen over Fe/Al2O3, Re/Al2O3 and Cr-Mn-O/Al2O3 catalysts

International Nuclear Information System (INIS)

Mirzabekova, S.R.; Mamedov, A.B.; Krylov, O.V.

1996-01-01

Regularities in CO 2 reduction have been studied using the systems Fe/Al 2 O 3 , Re/Al 2 O 3 and Cr-Mn-O/Al 2 O 3 under conditions of thermally programmed reaction by way of example. A sharp increase in the reduction rate in the course of CO 2 interaction with reduced Fe/Al 2 O 3 and Re/Al 2 O 3 , as well as with carbon fragments with addition in CO 2 flow of 1-2%H 2 , has been revealed. The assumption is made on intermediate formation of a formate in the process and on initiating effect of hydrogen on CO 2 reduction by the catalyst. Refs. 26, figs. 10

Single site porphyrine-like structures advantages over metals for selective electrochemical CO2 reduction

DEFF Research Database (Denmark)

Bagger, Alexander; Ju, Wen; Varela, Ana Sofia

2017-01-01

Currently, no catalysts are completely selective for the electrochemical CO2 Reduction Reaction (CO2RR). Based on trends in density functional theory calculations of reaction intermediates we find that the single metal site in a porphyrine-like structure has a simple advantage of limiting...... the competing Hydrogen Evolution Reaction (HER). The single metal site in a porphyrine-like structure requires an ontop site binding of hydrogen, compared to the hollow site binding of hydrogen on a metal catalyst surface. The difference in binding site structure gives a fundamental energy-shift in the scaling...... relation of ∼0.3eV between the COOH* vs. H* intermediate (CO2RR vs. HER). As a result, porphyrine-like catalysts have the advantage over metal catalyst of suppressing HER and enhancing CO2RR selectivity....

Electrochemical reduction of CO2 on compositionally variant Au-Pt bimetallic thin films

NARCIS (Netherlands)

Ma, M.; Hansen, H.A.; Valenti, M.; Wang, Z.; Cao, A.; Dong, M.; Smith, W.A.

2017-01-01

The electrocatalytic reduction of CO2 on Au-Pt bimetallic catalysts with different compositions was evaluated, offering a platform for uncovering the correlation between the catalytic activity and the surface composition of bimetallic electrocatalysts. The Au-Pt alloy films were synthesized by a

Biomimetic Polymeric Semiconductor Based Hybrid Nanosystems for Artificial Photosynthesis towards Solar Fuels Generation via CO₂ reduction

OpenAIRE

Zhou, H.; Li, P.; Liu, J.; Chen, Z.; Liu, L.; Dontsova, D.; Yan, R.; Fan, T.; Zhang, D.; Ye, J.

2016-01-01

In photosynthesis, an intricate polymeric system is constructed by connecting a light-harvesting antenna network, a molecular water oxidation center, and \\CO2\\} or proton-reduction machinery in a nanolayered architecture as a basic photosynthetic unit for solar-to-fuels conversion. Herein, we present a prototype basic artificial photosynthetic unit by connecting a typical CO2/proton reduction catalyst, a cocatalyst and an electron mediator as well as \\{CO2\\} activator into a polymer based nan...

NO{sub 2} and CO nonattainment areas: a pragmatic approach to source reduction assessment

Energy Technology Data Exchange (ETDEWEB)

Cernuschi, S.; Giugliano, M.; Marzolo, F. [D.I.I.A.R. - Politecnico di Milano, Milan (Italy). Environmental Section

1995-12-31

Many Italian large conurbations have CO and NO{sub 2} air quality standards exceeded and, consequently, require control enforcement plans to attain and maintain regulations not respected. In planning the interventions to be undertaken a fundamental issue is represented by the relationships between active emission sources and air quality, commonly described through mathematical models for evaluating the expected effects of the different reduction scenarios. This approach, relatively feasible for slightly or non reactive pollutants like CO, becomes not as easy to be applied for secondary pollutants, like NO{sub 2}, mainly for the complex photo chemical reaction systems involved in their atmospheric presence and the consequent modeling difficulties related either to the description of the system itself than to the detail in input data required. A practicable alternative in this framework relies in the utilization of statistical models for deriving, through the empirical description of the relationships between the parameters of interest, the reduction levels required for complying with the standards. Following an approach already applied with useful results to the same area, present work reports on the development and application to Milan urban area of statistical models for describing the relationships between CO and NO{sub x} annual concentration averages and the corresponding air quality standard parameters (number of standard exceedances for CO and 98th percentile of hourly concentrations for NO{sub 2}). The models are utilised upstream to simple roll-back models for the assessment of the reduction in emissions strength required for attaining air quality standards for the area. (author)

NO{sub 2} and CO nonattainment areas: a pragmatic approach to source reduction assessment

Energy Technology Data Exchange (ETDEWEB)

Cernuschi, S; Giugliano, M; Marzolo, F [D.I.I.A.R. - Politecnico di Milano, Milan (Italy). Environmental Section

1996-12-31

Many Italian large conurbations have CO and NO{sub 2} air quality standards exceeded and, consequently, require control enforcement plans to attain and maintain regulations not respected. In planning the interventions to be undertaken a fundamental issue is represented by the relationships between active emission sources and air quality, commonly described through mathematical models for evaluating the expected effects of the different reduction scenarios. This approach, relatively feasible for slightly or non reactive pollutants like CO, becomes not as easy to be applied for secondary pollutants, like NO{sub 2}, mainly for the complex photo chemical reaction systems involved in their atmospheric presence and the consequent modeling difficulties related either to the description of the system itself than to the detail in input data required. A practicable alternative in this framework relies in the utilization of statistical models for deriving, through the empirical description of the relationships between the parameters of interest, the reduction levels required for complying with the standards. Following an approach already applied with useful results to the same area, present work reports on the development and application to Milan urban area of statistical models for describing the relationships between CO and NO{sub x} annual concentration averages and the corresponding air quality standard parameters (number of standard exceedances for CO and 98th percentile of hourly concentrations for NO{sub 2}). The models are utilised upstream to simple roll-back models for the assessment of the reduction in emissions strength required for attaining air quality standards for the area. (author)

Oxygen reduction reaction on carbon-supported CoSe2 nanoparticles in an acidic medium

International Nuclear Information System (INIS)

Feng Yongjun; He Ting; Alonso-Vante, Nicolas

2009-01-01

We investigated the effect of CoSe 2 /C nanoparticle loading rate on oxygen reduction reaction (ORR) activity and H 2 O 2 production using the rotating disk electrode and the rotating ring-disk electrode techniques. We prepared carbon-supported CoSe 2 nanoparticles with different nominal loading rates and evaluated these samples by means of powder X-ray diffraction. All the catalysts had an OCP value of 0.81 V vs. RHE. H 2 O 2 production during the ORR process decreased with an increase in catalytic layer thickness. This decrease was related to the CoSe 2 loading on the disk electrode. H 2 O 2 production also decreased with increasing catalytic site density, a phenomenon related to the CoSe 2 loading rate on the carbon substrate. The cathodic current density significantly increased with increasing catalytic layer thickness, but decreased with increasing catalytic site density. In the case of 20 wt% CoSe 2 /C nanoparticles at 22 μg cm -2 , we determined that the transfer process involves about 3.5 electrons.

How light-harvesting semiconductors can alter the bias of reversible electrocatalysts in favor of H2 production and CO2 reduction.

Science.gov (United States)

Bachmeier, Andreas; Wang, Vincent C C; Woolerton, Thomas W; Bell, Sophie; Fontecilla-Camps, Juan C; Can, Mehmet; Ragsdale, Stephen W; Chaudhary, Yatendra S; Armstrong, Fraser A

2013-10-09

The most efficient catalysts for solar fuel production should operate close to reversible potentials, yet possess a bias for the fuel-forming direction. Protein film electrochemical studies of Ni-containing carbon monoxide dehydrogenase and [NiFeSe]-hydrogenase, each a reversible electrocatalyst, show that the electronic state of the electrode strongly biases the direction of electrocatalysis of CO2/CO and H(+)/H2 interconversions. Attached to graphite electrodes, these enzymes show high activities for both oxidation and reduction, but there is a marked shift in bias, in favor of CO2 or H(+) reduction, when the respective enzymes are attached instead to n-type semiconductor electrodes constructed from CdS and TiO2 nanoparticles. This catalytic rectification effect can arise for a reversible electrocatalyst attached to a semiconductor electrode if the electrode transforms between semiconductor- and metallic-like behavior across the same narrow potential range (<0.25 V) that the electrocatalytic current switches between oxidation and reduction.

Performance analysis of photocatalytic CO2 reduction in optical fiber monolith reactor with multiple inverse lights

International Nuclear Information System (INIS)

Yuan, Kai; Yang, Lijun; Du, Xiaoze; Yang, Yongping

2014-01-01

Highlights: • A new optical fiber monolith reactor model for CO 2 reduction was developed. • Methanol concentration versus fiber location and operation parameters was obtained. • Reaction efficiency increases by 31.1% due to the four fibers and inverse layout. • With increasing space of fiber and channel center, methanol concentration increases. • Methanol concentration increases as the vapor ratio and light intensity increase. - Abstract: Photocatalytic CO 2 reduction seems potential to mitigate greenhouse gas emissions and produce renewable energy. A new model of photocatalytic CO 2 reduction in optical fiber monolith reactor with multiple inverse lights was developed in this study to improve the conversion of CO 2 to CH 3 OH. The new light distribution equation was derived, by which the light distribution was modeled and analyzed. The variations of CH 3 OH concentration with the fiber location and operation parameters were obtained by means of numerical simulation. The results show that the outlet CH 3 OH concentration is 31.1% higher than the previous model, which is attributed to the four fibers and inverse layout. With the increase of the distance between the fiber and the monolith center, the average CH 3 OH concentration increases. The average CH 3 OH concentration also rises as the light input and water vapor percentage increase, but declines with increasing the inlet velocity. The maximum conversion rate and quantum efficiency in the model are 0.235 μmol g −1 h −1 and 0.0177% respectively, both higher than previous internally illuminated monolith reactor (0.16 μmol g −1 h −1 and 0.012%). The optical fiber monolith reactor layout with multiple inverse lights is recommended in the design of photocatalytic reactor of CO 2 reduction

Analysis of CO2, CO and HC emission reduction in automobiles

Science.gov (United States)

Balan, K. N.; Valarmathi, T. N.; Reddy, Mannem Soma Harish; Aravinda Reddy, Gireddy; Sai Srinivas, Jammalamadaka K. M. K.; Vasan

2017-05-01

In the present scenario, the emission from automobiles is becoming a serious problem to the environment. Automobiles, thermal power stations and Industries majorly constitute to the emission of CO2, CO and HC. Though the CO2 available in the atmosphere will be captured by oceans, grasslands; they are not enough to control CO2 present in the atmosphere completely. Also advances in engine and vehicle technology continuously to reduce the emission from engine exhaust are not sufficient to reduce the HC and CO emission. This work concentrates on design, fabrication and analysis to reduce CO2, CO and HC emission from exhaust of automobiles by using molecular sieve 5A of 1.5mm. In this paper, the details of the fabrication, results and discussion about the process are discussed.

Impact of Overlapping Fe/TiO2 Prepared by Sol-Gel and Dip-Coating Process on CO2 Reduction

Directory of Open Access Journals (Sweden)

Akira Nishimura

2016-01-01

Full Text Available Fe-doped TiO2 (Fe/TiO2 film photocatalyst was prepared by sol-gel and dip-coating process to extend its photoresponsivity to the visible spectrum. To promote the CO2 reduction performance with the photocatalyst, some types of base materials used for coating Fe/TiO2, which were netlike glass fiber and Cu disc, were investigated. The characterization of prepared Fe/TiO2 film coated on netlike glass fiber and Cu disc was analyzed by SEM and EPMA. In addition, the CO2 reduction performance of Fe/TiO2 film coated on netlike glass disc, Cu disc, and their overlap was tested under a Xe lamp with or without ultraviolet (UV light, respectively. The results show that the concentration of produced CO increases by Fe doping irrespective of base material used under the illumination condition with UV light as well as that without UV light. Since the electron transfer between two overlapped photocatalysts is promoted, the peak concentration of CO for the Fe/TiO2 double overlapping is approximately 1.5 times as large as the Fe/TiO2 single overlapping under the illumination condition with UV light, while the promotion ratio is approximately 1.1 times under that without UV light.

A Robust Pyridyl-NHC-Ligated Rhenium Photocatalyst for CO2 Reduction in the Presence of Water and Oxygen

Directory of Open Access Journals (Sweden)

Casey A. Carpenter

2018-01-01

Full Text Available Re(pyNHC-PhCF3(CO3Br is a highly active photocatalyst for CO2 reduction. The PhCF3 derivative was previously empirically shown to be a robust catalyst. Here, the role of the PhCF3 group is probed computationally and the robust nature of this catalyst is analyzed with regard to the presence of water and oxygen introduced in controlled amounts during the photocatalytic reduction of CO2 to CO with visible light. This complex was found to work well from 0–1% water concentration reproducibly; however, trace amounts of water were required for benchmark Re(bpy(CO3Cl to give reproducible reactivity. When ambient air is added to the reaction mixture, the NHC complex was found to retain substantial performance (~50% of optimized reactivity at up to 40% ambient atmosphere and 60% CO2 while the Re(bpy(CO3Cl complex was found to give a dramatically reduced CO2 reduction reactivity upon introduction of ambient atmosphere. Through the use of time-correlated single photon counting studies and prior electrochemical results, we reasoned that this enhanced catalyst resilience is due to a mechanistic difference between the NHC- and bpy-based catalysts. These results highlight an important feature of this NHC-ligated catalyst: substantially enhanced stability toward common reaction contaminates.

Reduction of CO/sub 2/ emissions through fuel economy standards for diesel cars in pakistan

International Nuclear Information System (INIS)

Memon, L.A.; Mehlia, T.M.I.; Hassan, M.H.

2007-01-01

In Pakistan, like many developing countries, the increasing prosperity and population growth are resulting in accelerated growth in vehicle population and vehicle kilometers traveled. This causes air pollution due to huge CO/sub 2/ emissions. Automobile fuel economy standards have proven to be one of the most effective tools to control oil demand thereby reducing the GHG (Green House Gas) emissions like CO/sub 2/, This study presents the investigation to apply fuel economy standards in Pakistan, in order to predict the potential reduction in CO/sub 2/ emissions and saving in fuel demand. The study is focused on only diesel cars and the data of diesel car owners for previous fifteen years is obtained from the related sources in Pakistan. A growth trend of diesel car owners was analyzed and the number of diesel car owners in future was predicted by applying database computer software. Calculations were made to study the effect of fuel economy standards in terms of saving in fuel demand and the reduction in CO/sub 2/ emissions. The results reveal the potential application of fuel economy standards and it was found that a cumulative amount of fuel 39266775 liters can be saved and CO/sub 2/ emissions can be reduced by 106021 tons at the end of 2011-2012, if fuel economy standards are implemented in 2008-2009. (author)

Electrochemical Reduction of CO2 on Compositionally Variant Au-Pt Bimetallic Thin Films

DEFF Research Database (Denmark)

Ma, Ming; Hansen, Heine Anton; Valenti, Marco

2017-01-01

The electrocatalytic reduction of CO2 on Au-Pt bimetallic catalysts with different compositions was evaluated, offering a platform for uncovering the correlation between the catalytic activity and the surface composition of bimetallic electrocatalysts. The Au-Pt alloy films were synthesized...... by a magnetron sputtering co-deposition technique with tunable composition. It was found that the syngas ratio (CO:H2) on the Au-Pt films is able to be tuned by systematically controlling the binary composition. This tunable catalytic selectivity is attributed to the variation of binding strength of COOH and CO...... intermediates, influenced by the surface electronic structure (d-band center energy) which is linked to the surface composition of the bimetallic films. Notably, a gradual shift of the d-band center away from the Fermi level was observed with increasing Au content, which correspondingly reduces the binding...

Strategic research on CO{sub 2} emission reduction for China. Application of MARKAL to China energy system

Energy Technology Data Exchange (ETDEWEB)

Yongping, Wang [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1995-09-01

MARKAL was applied to the energy system for analyzing the CO{sub 2} emission reduction in China over the time period from 1990 to 2050. First the Chinese Reference Energy System (CRES) was established based on the framework of MARKAL model. The following conclusions can be drawn from this study. When shifting from scenario LH (low useful energy demand and high import fuel prices) to HL (high demand and low prices), another 33 EJ of primary energy will be consumed and another 2.31 billion tons of CO{sub 2} will be emitted in 2050. Detailed analyses on the disaggregation of CO{sub 2} emissions by Kaya Formula show. The energy intensity (primary energy/GDP) decreases much faster in scenario HL, but the higher growth rate of GDP per capita is the overwhelming factor that results in higher CO{sub 2} emission per capita in the baseline case of scenario HL in comparison with LH. When the carbon taxes are imposed on CO{sub 2} emissions, the residential sector will make the biggest contribution to CO{sub 2} emission abatement from a long-term point of view. However, it`s difficult to stabilize CO{sub 2} emission per capita before 2030 in both scenarios even with heavy carbon taxes. When nuclear moratorium occurs, more 560 million tons of CO{sub 2} will be emitted to the atmosphere in 2050 under the same CO{sub 2} tax regime. From the analysis of value flow, CO{sub 2} emission reduction depends largely on new or advanced technologies particularly in the field of electricity generation. The competent technologies switch to those CO{sub 2} less-emitting technologies when surcharging CO{sub 2} emissions. Nuclear power shows significant potential in saving fossil energy resources and reducing CO{sub 2} emissions. (J.P.N.).

Photocatalytic reduction of CO2 into hydrocarbon solar fuels over g-C3N4-Pt nanocomposite photocatalysts.

Science.gov (United States)

Yu, Jiaguo; Wang, Ke; Xiao, Wei; Cheng, Bei

2014-06-21

Photocatalytic reduction of CO2 into renewable hydrocarbon fuels is an alternative way to develop reproducible energy, which is also a promising way to solve the problem of the greenhouse effect. In this work, graphitic carbon nitride (g-C3N4) was synthesized by directly heating thiourea at 550 °C and then a certain amount of Pt was deposited on it to form g-C3N4-Pt nanocomposites used as catalysts for photocatalytic reduction of CO2 under simulated solar irradiation. The main products of photocatalysis were CH4, CH3OH and HCHO. The deposited Pt acted as an effective cocatalyst, which not only influenced the selectivity of the product generation, but also affected the activity of the reaction. The yield of CH4 first increased upon increasing the amount of Pt deposited on the g-C3N4 from 0 to 1 wt%, then decreased at 2 wt% Pt loading. The production rates of CH3OH and HCHO also increased with the content of Pt increasing from 0 to 0.75 wt% and the maximum yield was observed at 0.75 wt%. The Pt nanoparticles (NPs) could facilitate the transfer and enrichment of photogenerated electrons from g-C3N4 to its surface for photocatalytic reduction of CO2. At the same time, Pt was also used a catalyst to promote the oxidation of products. The transient photocurrent response further confirmed the proposed photocatalytic reduction mechanism of CO2. This work indicates that the deposition of Pt is a good strategy to improve the photoactivity and selectivity of g-C3N4 for CO2 reduction.

Possible pathways for dealing with Japan's post-Fukushima challenge and achieving CO2 emission reduction targets in 2030

International Nuclear Information System (INIS)

Su, Xuanming; Zhou, Weisheng; Sun, Faming; Nakagami, Ken'Ichi

2014-01-01

Considering the unclear nuclear future of Japan after Fukushima Dai-ichi nuclear power plant accident since Mar. 11, 2011, this study assesses a series of energy consumption scenarios including the reference scenario, nuclear limited scenarios and current nuclear use level scenario for Japan in 2030 by the G-CEEP (Glocal Century Energy Environment Planning) model. The simulation result for each scenario is firstly presented in terms of primary energy consumption, electricity generation, CO 2 emission, marginal abatement cost and GDP (gross domestic product) loss. According to the results, energy saving contributes the biggest share in total CO 2 emission reduction, regardless of different nuclear use levels and different CO 2 emission reduction levels. A certain amount of coal generation can be retained in the nuclear limited scenarios due to the applying of CCS (carbon capture and storage). The discussion indicates that Japan needs to improve energy use efficiency, increase renewable energy and introduce CCS in order to reduce the dependence on nuclear power and to achieve CO 2 emission reduction target in 2030. In addition, it is ambitious for Japan to achieve the zero nuclear scenario with 30% CO 2 emission reduction which will cause a marginal abatement cost of 383 USD/tC and up to −2.54% GDP loss from the reference scenario. Dealing with the nuclear power issue, Japan is faced with a challenge as well as an opportunity. - Highlights: • Nuclear use limited and carbon emission reduction scenarios for Japan in 2030. • Contributions of different abatement options to carbon emissions. • CCS for reducing dependence on nuclear power

Exceptionally High Efficient Co-Co2P@N, P-Codoped Carbon Hybrid Catalyst for Visible Light-Driven CO2-to-CO Conversion.

Science.gov (United States)

Fu, Wen Gan

2018-05-02

Artificial photosynthesis has attracted wide attention, particularly the development of efficient solar light-driven methods to reduce CO2 to form energy-rich carbon-based products. Because CO2 reduction is an uphill process with a large energy barrier, suitable catalysts are necessary to achieve this transformation. In addition, CO2 adsorption on a catalyst and proton transfer to CO2 are two important factors for the conversion reaction，and catalysts with high surface area and more active sites are required to improve the efficiency of CO2 reduction. Here, we report a visible light-driven system for CO2-to-CO conversion that consists of a heterogeneous hybrid catalyst of Co and Co2P nanoparticles embedded in carbon nanolayers codoped with N and P (Co-Co2P@NPC) and a homogeneous Ru(II)-based complex photosensitizer. The average generation rate of CO of the system was up to 35,000 μmol h-1 g-1 with selectivity of 79.1% in 3 h. Linear CO production at an exceptionally high rate of 63,000 μmol h-1 g-1 was observed in the first hour of reaction. Inspired by this highly active catalyst, we also synthesized Co@NC and Co2P@NPC materials and explored their structure, morphology, and catalytic properties for CO2 photoreduction. The results showed that the nanoparticle size, partially adsorbed H2O molecules on the catalyst surface, and the hybrid nature of the systems influenced their photocatalytic CO2 reduction performance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An evaluation of the UK programme for CO{sub 2} reduction

Energy Technology Data Exchange (ETDEWEB)

Buchdahl, J.M.; Longhurst, J.W.S.; Rowe, E.J. [Manchester Metropolitan University, Manchester (United Kingdom). Atmospheric Research and Information Centre, Dept. of Environmental and Geographic Sciences

1995-12-31

This paper is concerned with an evaluation of the UK national programme for carbon dioxide (CO{sub 2}) emission reduction, in the context of the Framework Convention on Climate Change. It assesses whether the precautionary approach, as it stands, fully meets the objective of the FCCC (Articla 2), in the light of current scientific evidence. It examines the approach of one developed economy, the UK, in developing its national programme and also the major issues which may affect the attainment of emissions abatement targets. 13 refs., 3 tabs.

Regional CO2 budget, countermeasures and reduction aims for the Alpine tourist region of Davos, Switzerland

International Nuclear Information System (INIS)

Walz, A.; Calonder, G.-P.; Hagedorn, F.; Lardelli, C.; Lundstroem, C.; Stoeckli, V.

2008-01-01

In its latest report, the Intergovernmental Panel on Climate Change (IPCC) concludes that global climate change can still be slowed down if greenhouse gas emissions are rapidly and strongly reduced. We present a detailed regional CO 2 budget for the Alpine tourist region of Davos, Switzerland, including emissions and potential sinks. The aim of the study was (1) to estimate the most important CO 2 sources and sinks, (2) to identify the most efficient reduction measures and (3) to assess the feasibility of different reduction targets. The results show that the emissions due to heating contribute to a proportion of 86.3% to the total budget, which is mainly due to the harsh local climate and the tourism-focused local economy. They also show that the yearly CO 2 emissions per capita in Davos exceed the Swiss average of 6 tonnes by 25%. The augmentation of the carbon pool through the natural environment compares to 10.3% of the total emissions, and further afforestation of the community forest can contribute to an improvement of the total budget by 2.6%. The reduction aim of -15% until 2015 (compared with 2004), as set by the municipality itself, could be easily reached through better building insulation and the use of renewable energy sources. More ambitious aims, such as a 2000 W-society or CO 2 neutrality, however, will not be realised without major drawbacks in living standards

Catalytic reduction of NOx with H2/CO/CH4 over PdMOR catalysts

International Nuclear Information System (INIS)

Pieterse, Johannis A.Z.; Booneveld, Saskia

2007-01-01

Conversion of NO x with reducing agents H 2 , CO and CH 4 , with and without O 2 , H 2 O, and CO 2 were studied with catalysts based on MOR zeolite loaded with palladium and cerium. The catalysts reached high NO x to N 2 conversion with H 2 and CO (>90% conversion and N 2 selectivity) range under lean conditions. The formation of N 2 O is absent in the presence of both H 2 and CO together with oxygen in the feed, which will be the case in lean engine exhaust. PdMOR shows synergic co-operation between H 2 and CO at 450-500 K. The positive effect of cerium is significant in the case of H 2 and CH 4 reducing agent but is less obvious with H 2 /CO mixture and under lean conditions. Cerium lowers the reducibility of Pd species in the zeolite micropores. The catalysts showed excellent stability at temperatures up to 673 K in a feed with 2500 ppm CH 4 , 500 ppm NO, 5% O 2 , 10% H 2 O (0-1% H 2 ), N 2 balance but deactivation is noticed at higher temperatures. Combining results of the present study with those of previous studies it shows that the PdMOR-based catalysts are good catalysts for NO x reduction with H 2 , CO, hydrocarbons, alcohols and aldehydes under lean conditions at temperatures up to 673 K. (author)

Assessment of CO2 emission reduction and identification of CDM potential in a township

Energy Technology Data Exchange (ETDEWEB)

Misra, R.; Aseri, Tarun Kumar; Jamuwa, Doraj Karnal [Department of Mechanical Engineering, Government Engineering College, Ajmer, Rajasthan (India); Bansal, V. [Department of Mechanical Engineering, Government Mahila Engineering College, Ajmer, Rajasthan (India)

2012-11-15

This paper presents the theoretical investigation of CDM opportunity in a township at Jaipur, India. The purpose of study is to identify and analyze the various opportunities viz., installation of solar water heater, energy efficient lighting, energy efficient air conditioners, and energy efficient submersible water pumps in desert coolers and thus achieve a considerable (65.7 %) reduction in GHG emissions. Out of the various opportunities considered, the retrofitting with solar water heater can be recommended for CDM. Though, the retrofitting with energy efficient lighting, energy efficient air conditioners and energy efficient submersible water pumps in desert coolers claimed CO2 emission reduction of 104.84, 25.92, and 36.94 tons per annum, respectively, but the only opportunity which got through CDM was retrofitting with solar water heater claiming 115.70 tCO2 (100 %) emission reductions per annum which could result into net earnings of 115.70 CERs. The simple and discounted payback period for all four project activities are also calculated with and without CDM and tax benefits.

How to Achieve CO2 Emission Reduction Goals: What 'Jazz' and 'Symphony' Can Offer

International Nuclear Information System (INIS)

Rose, K.

2013-01-01

Achieving CO 2 emission reduction goals remains one of today's most challenging tasks. Global energy demand will grow for many decades to come. In many regions of the world cheap fossil fuels seem to be the way forward to meet ever growing energy demand. However, there are negative consequences to this, most notably increasing emission levels. Politicians and industry therefore must accept that make hard choices in this generation need to be made to bring about real changes for future generations and the planet to limit CO 2 emissions and climate change. In his presentation, prof. Rose will provide an insight into how CO 2 emission reduction goals can be set and achieved and how a balance between future energy needs and supply can be realised in the long run up to 2050 both globally and regionally. This will be done based on WEC's own leading analysis in this area, namely it recently launched World Energy Scenarios: composing energy futures to 2050 report and WEC's scenarios, Jazz and Symphony. WEC's full analysis, the complete report and supporting material is available online at: http://www.worldenergy.org/publications/2013/world-energy-scenarios-composing-energy-futures-to-2050.(author)

Cooperative Electrocatalytic O ₂ Reduction Involving Co(salophen) with p- Hydroquinone as an Electron–Proton Transfer Mediator

Energy Technology Data Exchange (ETDEWEB)

Anson, Colin W. [Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States; Stahl, Shannon S. [Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States

2017-12-01

The molecular cobalt complex, Co(salophen), and para-hydroquinone (H2Q) serve as effective cocatalysts for the electrochemical reduction of O2 to water. Mechanistic studies reveal redox cooperativity between Co(salophen) and H2Q. H2Q serves as an electron-proton transfer mediator (EPTM) that enables electrochemical O2 reduction at higher potentials and with faster rates than is observed with Co(salophen) alone. Replacement of H2Q with the higher potential EPTM, 2-chloro-H2Q, allows for faster O2 reduction rates at higher applied potential. These results demonstrate a unique strategy to achieve improved performance with molecular electrocatalyst systems.

Energy saving and CO2-reduction potential of micro-cogeneration in the Netherlands (2010-2030). Update 2008

International Nuclear Information System (INIS)

Van Gastel, M.; De Jong, A.; Schlatmann, S.; Bakker, E.J.; Jeeninga, H.; Boerakker, Y.; Seebregts, A.; Menkveld, M.; Van Wolferen, H.; Turkstra, J.W.; Dam, J.; Harmsen, R.; Rooijers, F.; Koot, M.

2008-05-01

Various parties have been asked to come to a joint point of view with regard to establishing the potential of micro CHP for energy saving and CO2 emission reduction in the Netherlands from 2010 to 2030, assuming that micro CHP will have a successful market introduction. The result of this memo is a method for determining the technical potential of micro CHP for the reduction of energy use and CO2 emissions. This report is an update of the 2006 report [mk] [nl

Microbial reduction of [Co(III)–EDTA]− by Bacillus licheniformis SPB-2 strain isolated from a solar salt pan

International Nuclear Information System (INIS)

Paraneeiswaran, Arunachalam; Shukla, Sudhir K.; Prashanth, K.; Rao, T. Subba

2015-01-01

Graphical abstract: - Highlights: • Bacillus licheniformis SPB-2 was used in the bioremediation of [Co(III)–EDTA] − . • The bacterial biomass adsorbed the Co–EDTA complex after its reduction. • [Co(III)–EDTA] − complex showed Bacillus spore inducing property. • B. licheniformis SPB-2 showed significantly radio-tolerance (D 10 = 250 Gy). - Abstract: Naturally stressed habitats are known to be repositories for novel microorganisms with potential bioremediation applications. In this study, we isolated a [Co(III)–EDTA] − reducing bacterium Bacillus licheniformis SPB-2 from a solar salt pan that is exposed to constant cycles of hydration and desiccation in nature. [Co(III)–EDTA] − generated during nuclear waste management process is difficult to remove from the waste due to its high stability and solubility. It is reduced form i.e. [Co(II)–EDTA] 2− is less stable though it is toxic. This study showed that B. licheniformis SPB-2 reduced 1 mM [Co(III)–EDTA] − in 14 days when grown in a batch mode. However, subsequent cycles showed an increase in the reduction activity, which was observed up to four cycles. Interestingly, the present study also showed that [Co(III)–EDTA] − acted as an inducer for B. licheniformis SPB-2 spore germination. Vegetative cells germinated from the spores were found to be involved in [Co(III)–EDTA] − reduction. More detailed investigations showed that after [Co(III)–EDTA] − reduction, i.e. [Co(II)–EDTA] 2− complex was removed by B. licheniformis SPB-2 from the bulk liquid by adsorption phenomenon. The bacterium showed a D 10 value (radiation dose required to kill 90% cells) of ∼250 Gray (Gy), which signifies the potential use of B. licheniformis SPB-2 for bioremediation of moderately active nuclear waste

Catalytic reduction of NO and N20 for CO on Co-ZSM-5

International Nuclear Information System (INIS)

Rios, Luis Alberto; Aristizabal, Gladys Liliana; Ruiz, Julio Fernando; Montes Consuelo

1996-01-01

Several catalysts with the help of ZSM-5 with Co were tested in the catalytic reduction of NO and N2O using CO like agent reducer and in presence of variable quantities of O2 The cobalt incorporated in the zeolite ZSM-5 for the methods of ionic exchange, impregnation and substitution. ZSM-5 exchanged with Co presented the highest conversions of NO (80% to 5OO oC), in presence of 3000 ppm of O2; When adding 25.700 ppm of O2 the conversion it diminished notably, that which shows an effect inhibitor of the O2. The substituted catalysts and impregnated they were less active for the reduction of the NO. With all the catalysts conversions of 70-90% were achieved for the N2O; Additionally, marked deactivation of the catalyst was not presented with the time

Microbial reduction of [Co(III)-EDTA]⁻ by Bacillus licheniformis SPB-2 strain isolated from a solar salt pan.

Science.gov (United States)

Paraneeiswaran, Arunachalam; Shukla, Sudhir K; Prashanth, K; Rao, T Subba

2015-01-01

Naturally stressed habitats are known to be repositories for novel microorganisms with potential bioremediation applications. In this study, we isolated a [Co(III)-EDTA](-) reducing bacterium Bacillus licheniformis SPB-2 from a solar salt pan that is exposed to constant cycles of hydration and desiccation in nature. [Co(III)-EDTA](-) generated during nuclear waste management process is difficult to remove from the waste due to its high stability and solubility. It is reduced form i.e. [Co(II)-EDTA](2-) is less stable though it is toxic. This study showed that B. licheniformis SPB-2 reduced 1mM [Co(III)-EDTA](-) in 14 days when grown in a batch mode. However, subsequent cycles showed an increase in the reduction activity, which was observed up to four cycles. Interestingly, the present study also showed that [Co(III)-EDTA](-) acted as an inducer for B. licheniformis SPB-2 spore germination. Vegetative cells germinated from the spores were found to be involved in [Co(III)-EDTA](-) reduction. More detailed investigations showed that after [Co(III)-EDTA](-) reduction, i.e. [Co(II)-EDTA](2-) complex was removed by B. licheniformis SPB-2 from the bulk liquid by adsorption phenomenon. The bacterium showed a D10 value (radiation dose required to kill 90% cells) of ∼250 Gray (Gy), which signifies the potential use of B. licheniformis SPB-2 for bioremediation of moderately active nuclear waste. Copyright © 2014 Elsevier B.V. All rights reserved.

Growth of single-crystal W whiskers during humid H2/N2 reduction of Ni, Fe-Ni, and Co-Ni doped tungsten oxide

International Nuclear Information System (INIS)

Wang Shiliang; He Yuehui; Zou Jou; Wang Yong; Huang Han

2009-01-01

Numbers of W whiskers were obtained by reducing Ni, Ni-Fe, and Ni-Co doped tungsten oxide in a mixed atmosphere of humid H 2 and N 2 . The phases and morphologies of the reduction products were characterized by XRD and SEM. Intensive TEM and EDS analyses showed that the obtained whiskers were W single crystals which typical have alloyed particles (Ni-W, Fe-Ni, or Co-Ni-W) at the growth tips. The formed W whiskers were presumed to be induced by the alloyed particles. Our experimental results revealed that, during the reduction process of tungsten oxide, the pre-reduced Ni, Fe-Ni, or Co-Ni particles not only served as nucleation aids for the initial growth of W phase from W oxide but also played the roles of catalysts during the reductive decomposition of gaseous WO 2 (OH) 2 .

Modelling the aqueous and nonaqueous interfaces for CO2 electro-reduction over Sn catalysts

Science.gov (United States)

Sheng, Tian; Sun, Shi-Gang

2018-01-01

In CO2 electroreduction, Sn catalysts with a high overpotential for hydrogen evolution reaction and a high selectivity towards formic acid formation are very attractive. Many efforts have been made for improving the catalytic performance and for understanding the mechanisms. In electrochemistry, the role of solvents for surface reactions was deserved to be investigated, in particular for some nonaqueous solvents. Here, we have modeled the aqueous (water) and nonaqueous (acetonitrile and dichloromethane) for investigation of CO2 electroreduction on Sn surface, by constrained ab initio molecular dynamics simulations and thermodynamic integrations, including a number of explicit solvent molecules in computational models. It was found that CO2 reduction is initiated from formate formation and solvents, in particular, water can effectively facilitate the reaction.

A Hierarchical Z-Scheme α-Fe2 O3 /g-C3 N4 Hybrid for Enhanced Photocatalytic CO2 Reduction.

Science.gov (United States)

Jiang, Zhifeng; Wan, Weiming; Li, Huaming; Yuan, Shouqi; Zhao, Huijun; Wong, Po Keung

2018-03-01

The challenge in the artificial photosynthesis of fossil resources from CO 2 by utilizing solar energy is to achieve stable photocatalysts with effective CO 2 adsorption capacity and high charge-separation efficiency. A hierarchical direct Z-scheme system consisting of urchin-like hematite and carbon nitride provides an enhanced photocatalytic activity of reduction of CO 2 to CO, yielding a CO evolution rate of 27.2 µmol g -1 h -1 without cocatalyst and sacrifice reagent, which is >2.2 times higher than that produced by g-C 3 N 4 alone (10.3 µmol g -1 h -1 ). The enhanced photocatalytic activity of the Z-scheme hybrid material can be ascribed to its unique characteristics to accelerate the reduction process, including: (i) 3D hierarchical structure of urchin-like hematite and preferable basic sites which promotes the CO 2 adsorption, and (ii) the unique Z-scheme feature efficiently promotes the separation of the electron-hole pairs and enhances the reducibility of electrons in the conduction band of the g-C 3 N 4 . The origin of such an obvious advantage of the hierarchical Z-scheme is not only explained based on the experimental data but also investigated by modeling CO 2 adsorption and CO adsorption on the three different atomic-scale surfaces via density functional theory calculation. The study creates new opportunities for hierarchical hematite and other metal-oxide-based Z-scheme system for solar fuel generation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low Overpotential and High Current CO2 Reduction with Surface Reconstructed Cu Foam Electrodess

KAUST Repository

Min, Shixiong; Yang, Xiulin; Lu, Ang-Yu; Tseng, Chien-Chih; Hedhili, Mohamed N.; Li, Lain-Jong; Huang, Kuo-Wei

2016-01-01

for large-scale fuel synthesis. Here we report an extremely high current density for CO2 reduction at low overpotential using a Cu foam electrode prepared by air-oxidation and subsequent electroreduction. Apart from possessing three-dimensional (3D) open

Recurrent intergrowths in the topotactic reduction process of LaBaCuCoO5.2.

Science.gov (United States)

Ruiz-González, Luisa; Boulahya, Khalid; Parras, Marina; Alonso, José; González-Calbet, José M

2002-12-16

A new perovskite-related oxide with the LaBaCuCoO5.2 composition has been stabilised. Its structure can be described as formed by the recurrent intergrowth of two alternating blocks of YBaCuFeO5 (2ac, i.e., two-fold perovskite superlattice) and YBa2Fe3O8 (3ac) structural types. From the starting material LaBaCuCoO5.2-delta (delta = 0), the rigorous control of the oxygen content has allowed the stabilisation of three new five fold perovskite-related superstructures with the compositions delta = 0.4, 0.8 and 1.1, which can also be described as recurrent intergrowths of two blocks showing 2ac and 3ac periodicity. The reduction process takes place through the 3ac periodic blocks, when 0 topotactic reaction, since their basic structure is kept through the reduction process.

Prediction of the viscosity reduction due to dissolved CO2 of and an elementary approach in the supercritical CO2 assisted continuous particle production of a polyester resin

NARCIS (Netherlands)

Nalawade, Sameer P.; Nieborg, Vincent H. J.; Picchioni, Francesco; Janssen, L. P. B. M.

2006-01-01

The dissolution of CO2 in a polymer causes plasticization of the polymer and hence, its viscosity is reduced. A model based on the free volume theory has been used for a polyester resin, which shows a considerable reduction in the viscosity due to dissolved M. Therefore, superctitical CO2 has been

Detection of CO2•- in the Electrochemical Reduction of Carbon Dioxide in N,N-Dimethylformamide by Scanning Electrochemical Microscopy.

Science.gov (United States)

Kai, Tianhan; Zhou, Min; Duan, Zhiyao; Henkelman, Graeme A; Bard, Allen J

2017-12-27

The electrocatalytic reduction of CO 2 has been studied extensively and produces a number of products. The initial reaction in the CO 2 reduction is often taken to be the 1e formation of the radical anion, CO 2 •- . However, the electrochemical detection and characterization of CO 2 •- is challenging because of the short lifetime of CO 2 •- , which can dimerize and react with proton donors and even mild oxidants. Here, we report the generation and quantitative determination of CO 2 •- in N,N-dimethylformamide (DMF) with the tip generation/substrate collection (TG/SC) mode of scanning electrochemical microscopy (SECM). CO 2 was reduced at a hemisphere-shaped Hg/Pt ultramicroelectrode (UME) or a Hg/Au film UME, which were utilized as the SECM tips. The CO 2 •- produced can either dimerize to form oxalate within the nanogap between SECM tip and substrate or collected at SECM substrate (e.g., an Au UME). The collection efficiency (CE) for CO 2 •- depends on the distance (d) between the tip and substrate. The dimerization rate (6.0 × 10 8 M -1 s -1 ) and half-life (10 ns) of CO 2 •- can be evaluated by fitting the collection efficiency vs distance curve. The dimerized species of CO 2 •- , oxalate, can also be determined quantitatively. Furthermore, the formal potential (E 0 ') and heterogeneous rate constant (k 0 ) for CO 2 reduction were determined with different quaternary ammonium electrolytes. The significant difference in k 0 is due to a tunneling effect caused by the adsorption of the electrolytes on the electrode surface at negative potentials.

Reduction of CO2 Emissions in Houses of Historic and Visual Importance

Directory of Open Access Journals (Sweden)

Birgit Dulski

2010-01-01

Full Text Available According to the ‘Climate Programme’ the municipality of Amsterdam has the ambition to reduce the CO2 emissions within the city limits by 40% in the year 2025 compared to the year 1990. To realize this ambition substantial CO2 savings have to be realized at the 375,000 current houses in the city. A special challenge is formed by the houses of historic and visual importance, as the implementation of standard energy saving measures may conflict with the ambition to protect their cultural and historic values. Nyenrode Business University was asked to study the possibilities for a successful combination of ambitions in both fields. This article shows an overview of suggestions that focus on the combination of technical and process orientated innovations which can contribute to the acceleration of the reduction of CO2 emissions in houses of historic and visual importance. The article therefore addresses political and technical as well as financial and process related aspects in implementing energy saving measures in this category of buildings.

Uncertainty quantification of CO2 emission reduction for maritime shipping

International Nuclear Information System (INIS)

Yuan, Jun; Ng, Szu Hui; Sou, Weng Sut

2016-01-01

The International Maritime Organization (IMO) has recently proposed several operational and technical measures to improve shipping efficiency and reduce the greenhouse gases (GHG) emissions. The abatement potentials estimated for these measures have been further used by many organizations to project future GHG emission reductions and plot Marginal Abatement Cost Curves (MACC). However, the abatement potentials estimated for many of these measures can be highly uncertain as many of these measures are new, with limited sea trial information. Furthermore, the abatements obtained are highly dependent on ocean conditions, trading routes and sailing patterns. When the estimated abatement potentials are used for projections, these ‘input’ uncertainties are often not clearly displayed or accounted for, which can lead to overly optimistic or pessimistic outlooks. In this paper, we propose a methodology to systematically quantify and account for these input uncertainties on the overall abatement potential forecasts. We further propose improvements to MACCs to better reflect the uncertainties in marginal abatement costs and total emissions. This approach provides a fuller and more accurate picture of abatement forecasts and potential reductions achievable, and will be useful to policy makers and decision makers in the shipping industry to better assess the cost effective measures for CO 2 emission reduction. - Highlights: • We propose a systematic method to quantify uncertainty in emission reduction. • Marginal abatement cost curves are improved to better reflect the uncertainties. • Percentage reduction probability is given to determine emission reduction target. • The methodology is applied to a case study on maritime shipping.

Photoelectrocatalytic reduction of CO2 into chemicals using Pt-modified reduced graphene oxide combined with Pt-modified TiO2 nanotubes.

Science.gov (United States)

Cheng, Jun; Zhang, Meng; Wu, Gai; Wang, Xin; Zhou, Junhu; Cen, Kefa

2014-06-17

The photoelectrocatalytic (PEC) reduction of CO2 into high-value chemicals is beneficial in alleviating global warming and advancing a low-carbon economy. In this work, Pt-modified reduced graphene oxide (Pt-RGO) and Pt-modified TiO2 nanotubes (Pt-TNT) were combined as cathode and photoanode catalysts, respectively, to form a PEC reactor for converting CO2 into valuable chemicals. XRD, XPS, TEM, AFM, and SEM were employed to characterize the microstructures of the Pt-RGO and Pt-TNT catalysts. Reduction products, such as C2H5OH and CH3COOH, were obtained from CO2 under band gap illumination and biased voltage. A combined liquid product generation rate (CH3OH, C2H5OH, HCOOH, and CH3COOH) of approximately 600 nmol/(h·cm(2)) was observed. Carbon atom conversion rate reached 1,130 nmol/(h·cm(2)), which were much higher than those achieved using Pt-modified carbon nanotubes and platinum carbon as cathode catalysts.

What is a fair CO2 tax increase? On fair emission reductions in the transport sector

International Nuclear Information System (INIS)

Hammar, Henrik; Jagers, Sverker C.

2007-01-01

We examine how individual preferences for fair reductions of carbon dioxide (CO 2 ) emissions affect the support for increases in the CO 2 tax on gasoline and diesel. We assume that people not only care about their own material welfare, but also have preferences for fairness in policy design, and we explore the implications using original data from a mail questionnaire sent to a representative sample of the Swedish population. The main result is that fairness in policy design does matter. Those respondents who adhere to a fairness principle tend to be relatively more positive to increases in the CO 2 tax. One possible explanation for this result is that there is a relatively high degree of reciprocity regarding the origin of emissions and the fairness regarding who should bear the burden of CO 2 reductions. Via a split sample analysis, we also find that the relative importance of fairness principles is dependent upon whether one uses a car often or not. This sheds light on the potential goal conflict between the importance of fairness principles and self-interest in the form of a need for private car transportation. (author)

Role of the adsorbed oxygen species in the selective electrochemical reduction of CO_2 to alcohols and carbonyls on copper electrodes

International Nuclear Information System (INIS)

Le Duff, Cecile S.; Lawrence, Matthew J.; Rodriguez, Paramaconi

2017-01-01

The electrochemical reduction of CO_2 into fuels has gained significant attention recently as source of renewable carbon-based fuels. The unique high selectivity of copper in the electrochemical reduction of CO_2 to hydrocarbons has called much interest in discovering its mechanism. In order to provide significant information about the role of oxygen in the electrochemical reduction of CO_2 on Cu electrodes, the conditions of the surface structure and the composition of the Cu single crystal electrodes were controlled over time. This was achieved using pulsed voltammetry, since the pulse sequence can be programmed to guarantee reproducible initial conditions for the reaction at every fraction of time and at a given frequency. In contrast to the selectivity of CO_2 reduction using cyclic voltammetry and chronoamperometric methods, a large selection of oxygenated hydrocarbons was found under alternating voltage conditions. Product selectivity towards the formation of oxygenated hydrocarbon was associated to the coverage of oxygen species, which is surface-structure- and potential-dependent. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

How can China reach its CO2 intensity reduction targets by 2020? A regional allocation based on equity and development

International Nuclear Information System (INIS)

Yi Wenjing; Zou Lele; Guo Jie; Wang Kai; Wei Yiming

2011-01-01

In late 2009, the Chinese government committed to cut its carbon dioxide emissions per unit of gross domestic product (GDP) by 40% to 45% of 2005 levels by 2020. This has raised the issue of how to allocate the CO 2 reduction target regionally to meet the national reduction target. To meet this objective, the following aspects may be taken into consideration: equity principles, 'common but differentiated responsibilities'; intensity reduction target fulfillment; and economic difference and reduction potential among provinces. This paper selects per capita GDP, accumulated fossil fuel related CO 2 emissions and energy consumption per unit of industrial added value as indicators for emission reduction capacity, responsibility and potential, respectively. Based on these three indicators, a comprehensive index is developed and an intensity allocation model constructed. As decision makers may have different preferences when allocating the reduction burden, we allocate different weights to the indicators, analyzing the results using cluster analysis. The following aspects may also be considered together with the national regional development strategy to determine how to share the burden: the reduction potential of various regions; implementation potential of the plans; and promotion of a highly efficient low carbon economic development model. - Research highlights: → We compiled a comprehensive index using per capita GDP, accumulated fossil fuel related CO 2 emissions and energy consumption per unit of industrial added value as indicators for emission reduction capacity, responsibility and potential, respectively. → National CO 2 intensity reduction target is allocated according to different index values of provinces. → Equity principles were taken into account when allocating the target.

Method to reduce CO.sub.2 to CO using plasmon-enhanced photocatalysis

Science.gov (United States)

Huber, George W.; Upadhye, Aniruddha A.; Kim, Hyung Ju; Ro, Insoo; Tejedor-Anderson, M. Isabel

2017-08-22

Described is a method of reducing CO.sub.2 to CO using visible radiation and plasmonic photocatalysts. The method includes contacting CO.sub.2 with a catalyst, in the presence of H.sub.2, wherein the catalyst has plasmonic photocatalytic reductive activity when exposed to radiation having a wavelength between 380 nm and 780 nm. The catalyst, CO.sub.2, and H.sub.2 are exposed to non-coherent radiation having a wavelength between 380 nm and 780 nm such that the catalyst undergoes surface plasmon resonance. The surface plasmon resonance increases the rate of CO.sub.2 reduction to CO as compared to the rate of CO.sub.2 reduction to CO without surface plasmon resonance in the catalyst.

Promoting Ethylene Selectivity from CO2 Electroreduction on CuO Supported onto CO2 Capture Materials.

Science.gov (United States)

Yang, Hui-Juan; Yang, Hong; Hong, Yu-Hao; Zhang, Peng-Yang; Wang, Tao; Chen, Li-Na; Zhang, Feng-Yang; Wu, Qi-Hui; Tian, Na; Zhou, Zhi-You; Sun, Shi-Gang

2018-03-09

Cu is a unique catalyst for CO 2 electroreduction, since it can catalyze CO 2 reduction to a series of hydrocarbons, alcohols, and carboxylic acids. Nevertheless, such Cu catalysts suffer from poor selectivity. High pressure of CO 2 is considered to facilitate the activity and selectivity of CO 2 reduction. Herein, a new strategy is presented for CO 2 reduction with improved C 2 H 4 selectivity on a Cu catalyst by using CO 2 capture materials as the support at ambient pressure. N-doped carbon (N x C) was synthesized through high-temperature carbonization of melamine and l-lysine. We observed that the CO 2 uptake capacity of N x C depends on both the microporous area and the content of pyridinic N species, which can be controlled by the carbonization temperature (600-800 °C). The as-prepared CuO/N x C catalysts exhibit a considerably higher C 2 H 4 faradaic efficiency (36 %) than CuO supported on XC-72 carbon black (19 %), or unsupported CuO (20 %). Moreover, there is a good linear relationship between the C 2 H 4 faradaic efficiency and CO 2 uptake capacity of the supports for CuO. The local high CO 2 concentration near Cu catalysts, created by CO 2 capture materials, was proposed to increase the coverage of CO intermediate, which is favorable for the coupling of two CO units in the formation of C 2 H 4 . This study demonstrates that pairing Cu catalysts with CO 2 capture supports is a promising approach for designing highly effective CO 2 reduction electrocatalysts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reduction of CO2 emission by INCAM model in Malaysia biomass power plants during the year 2016.

Science.gov (United States)

Amin, Nor Aishah Saidina; Talebian-Kiakalaieh, Amin

2018-03-01

As the world's second largest palm oil producer and exporter, Malaysia could capitalize on its oil palm biomass waste for power generation. The emission factors from this renewable energy source are far lower than that of fossil fuels. This study applies an integrated carbon accounting and mitigation (INCAM) model to calculate the amount of CO 2 emissions from two biomass thermal power plants. The CO 2 emissions released from biomass plants utilizing empty fruit bunch (EFB) and palm oil mill effluent (POME), as alternative fuels for powering steam and gas turbines, were determined using the INCAM model. Each section emitting CO 2 in the power plant, known as the carbon accounting center (CAC), was measured for its carbon profile (CP) and carbon index (CI). The carbon performance indicator (CPI) included electricity, fuel and water consumption, solid waste and waste-water generation. The carbon emission index (CEI) and carbon emission profile (CEP), based on the total monthly carbon production, were determined across the CPI. Various innovative strategies resulted in a 20%-90% reduction of CO 2 emissions. The implementation of reduction strategies significantly reduced the CO 2 emission levels. Based on the model, utilization of EFB and POME in the facilities could significantly reduce the CO 2 emissions and increase the potential for waste to energy initiatives. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of Energy Efficiency Improvement and CO2 Emission Reduction Potentials in India's Cement Industry

Energy Technology Data Exchange (ETDEWEB)

Morrow, III, William R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Xu, Tengfang [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-12-03

India’s cement industry is the second largest in the world behind China with annual cement production of 168 Mt in 2010 which accounted for slightly greater than six percent of the world’s annual cement production in the same year. To produce that amount of cement, the industry consumed roughly 700 PJ of fuel and 14.7 TWh of electricity. We identified and analyzed 22 energy efficiency technologies and measures applicable to the processes in the Indian cement industry. The Conservation Supply Curve (CSC) used in this study is an analytical tool that captures both the engineering and the economic perspectives of energy conservation. Using a bottom-up electricity CSC model and compared to an electricity price forecast the cumulative cost-effective plant-level electricity savings potential for the Indian cement industry for 2010- 2030 is estimated to be 83 TWh, and the cumulative plant-level technical electricity saving potential is 89 TWh during the same period. The grid-level CO2 emissions reduction associated with cost-effective electricity savings is 82 Mt CO2 and the electric grid-level CO2 emission reduction associated with technical electricity saving potential is 88 Mt CO2. Compared to a fuel price forecast, an estimated cumulative cost-effective fuel savings potential of 1,029 PJ with associated CO2 emission reduction of 97 Mt CO2 during 2010-2030 is possible. In addition, a sensitivity analysis with respect to the discount rate used is conducted to assess the effect of changes in this parameter on the results. The result of this study gives a comprehensive and easy to understand perspective to the Indian cement industry and policy makers about the energy efficiency potential and its associated cost over the next twenty years.

Carbon dioxide sequestration by mineral carbonation. Feasibility of enhanced natural weathering as a CO2 emission reduction technology

International Nuclear Information System (INIS)

Huijgen, W.J.J.

2007-01-01

A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept behind mineral CO2 sequestration is the mimicking of natural weathering processes in which calcium or magnesium containing minerals react with gaseous CO2 and form solid calcium or magnesium carbonates. Potential advantages of mineral CO2 sequestration compared to, e.g., geological CO2 storage include (1) the permanent and inherently safe sequestration of CO2, due to the thermodynamic stability of the carbonate product formed and (2) the vast potential sequestration capacity, because of the widespread and abundant occurrence of suitable feedstock. In addition, carbonation is an exothermic process, which potentially limits the overall energy consumption and costs of CO2 emission reduction. However, weathering processes are slow, with timescales at natural conditions of thousands to millions of years. For industrial implementation, a reduction of the reaction time to the order of minutes has to be achieved by developing alternative process routes. The aim of this thesis is an investigation of the technical, energetic, and economic feasibility of CO2 sequestration by mineral carbonation. In Chapter 1 the literature published on CO2 sequestration by mineral carbonation is reviewed. Among the potentially suitable mineral feedstock for mineral CO2 sequestration, Ca-silicates, more particularly wollastonite (CaSiO3), a mineral ore, and steel slag, an industrial alkaline solid residue, are selected for further research. Alkaline Ca-rich residues seem particularly promising, since these materials are inexpensive and available near large industrial point sources of CO2. In addition, residues tend to react relatively rapidly with CO2 due to their (geo)chemical instability. Various process routes have been proposed for mineral carbonation, which often include a pre-treatment of the solid feedstock (e.g., size reduction and

Dynamics of soil CO2 efflux under varying atmospheric CO2 concentrations reveal dominance of slow processes.

Science.gov (United States)

Kim, Dohyoung; Oren, Ram; Clark, James S; Palmroth, Sari; Oishi, A Christopher; McCarthy, Heather R; Maier, Chris A; Johnsen, Kurt

2017-09-01

We evaluated the effect on soil CO 2 efflux (F CO 2 ) of sudden changes in photosynthetic rates by altering CO 2 concentration in plots subjected to +200 ppmv for 15 years. Five-day intervals of exposure to elevated CO 2 (eCO 2 ) ranging 1.0-1.8 times ambient did not affect F CO 2 . F CO 2 did not decrease until 4 months after termination of the long-term eCO 2 treatment, longer than the 10 days observed for decrease of F CO 2 after experimental blocking of C flow to belowground, but shorter than the ~13 months it took for increase of F CO 2 following the initiation of eCO 2 . The reduction of F CO 2 upon termination of enrichment (~35%) cannot be explained by the reduction of leaf area (~15%) and associated carbohydrate production and allocation, suggesting a disproportionate contraction of the belowground ecosystem components; this was consistent with the reductions in base respiration and F CO 2 -temperature sensitivity. These asymmetric responses pose a tractable challenge to process-based models attempting to isolate the effect of individual processes on F CO2 . © 2017 John Wiley & Sons Ltd.

Emissions of CO2 from road freight transport in London: Trends and policies for long run reductions

International Nuclear Information System (INIS)

Zanni, Alberto M.; Bristow, Abigail L.

2010-01-01

Freight transport has been receiving increasing attention in both literature and practice following the growing recognition of its importance in urban transport planning. This paper analyses historical and projected road freight CO 2 emissions in the city of London and explores the potential mitigation effect of a set of freight transport policies and logistics solutions. Findings indicate a range of policies with potential to reduce emissions in the period up to 2050. However, this reduction would appear to only be capable of partly counterbalancing the projected increase in freight traffic. More profound behavioural measures therefore appear to be necessary for London's CO 2 emissions reduction targets to be met.

Role of the adsorbed oxygen species in the selective electrochemical reduction of CO{sub 2} to alcohols and carbonyls on copper electrodes

Energy Technology Data Exchange (ETDEWEB)

Le Duff, Cecile S.; Lawrence, Matthew J.; Rodriguez, Paramaconi [School of Chemistry, University of Birmingham, Edgbaston (United Kingdom)

2017-10-09

The electrochemical reduction of CO{sub 2} into fuels has gained significant attention recently as source of renewable carbon-based fuels. The unique high selectivity of copper in the electrochemical reduction of CO{sub 2} to hydrocarbons has called much interest in discovering its mechanism. In order to provide significant information about the role of oxygen in the electrochemical reduction of CO{sub 2} on Cu electrodes, the conditions of the surface structure and the composition of the Cu single crystal electrodes were controlled over time. This was achieved using pulsed voltammetry, since the pulse sequence can be programmed to guarantee reproducible initial conditions for the reaction at every fraction of time and at a given frequency. In contrast to the selectivity of CO{sub 2} reduction using cyclic voltammetry and chronoamperometric methods, a large selection of oxygenated hydrocarbons was found under alternating voltage conditions. Product selectivity towards the formation of oxygenated hydrocarbon was associated to the coverage of oxygen species, which is surface-structure- and potential-dependent. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

The application of CFD modelling to support the reduction of CO2 emissions in cement industry

International Nuclear Information System (INIS)

Mikulčić, Hrvoje; Vujanović, Milan; Fidaros, Dimitris K.; Priesching, Peter; Minić, Ivica; Tatschl, Reinhard; Duić, Neven; Stefanović, Gordana

2012-01-01

The cement industry is one of the leading producers of anthropogenic greenhouse gases, of which CO 2 is the most significant. Recently, researchers have invested a considerable amount of time studying ways to improve energy consumption and pollutant formation in the overall cement manufacturing process. One idea involves dividing the calcination and clinkering processes into two separate furnaces. The calcination process is performed in a calciner while the clinkering process takes place in a rotary kiln. As this is new technology in the cement manufacturing process, calciners are still in the research and development phase. The purpose of this paper is to demonstrate the potential of CFD to support the design and optimization of calciners, whose use appears to be essential in reduction of CO 2 emission during cement production. The mathematical model of the calcination process was developed, validated and implemented into a commercial CFD code, which was then used for the analysis. From the results obtained by these simulations, researchers will gain an in-depth understanding of all thermo-chemical reactions in a calciner. This understanding can be used to optimize the calciner's geometry, to make production more efficient, to lower pollutant formation and to subsequently reduce greenhouse gas emissions. -- Highlights: ► The potential of CO 2 emissions reduction, by using a cement calciner was presented. ► When a cement calciner is used, CO 2 emissions reduction of 3–4% can be achieved. ► The calcination model was developed, validated, and then used for the analysis. ► Shown method can be applied for investigation and optimization of cement calciners.

Solution Synthesis, Structure, and CO2 Reduction Reactivity of a Scandium(II) Complex, {Sc[N(SiMe3 )2 ]3 }.

Science.gov (United States)

Woen, David H; Chen, Guo P; Ziller, Joseph W; Boyle, Timothy J; Furche, Filipp; Evans, William J

2017-02-13

The first crystallographically characterizable complex of Sc 2+ , [Sc(NR 2 ) 3 ] - (R=SiMe 3 ), has been obtained by LnA 3 /M reactions (Ln=rare earth metal; A=anionic ligand; M=alkali metal) involving reduction of Sc(NR 2 ) 3 with K in the presence of 2.2.2-cryptand (crypt) and 18-crown-6 (18-c-6) and with Cs in the presence of crypt. Dark maroon [K(crypt)] + , [K(18-c-6)] + , and [Cs(crypt)] + salts of the [Sc(NR 2 ) 3 ] - anion are formed, respectively. The formation of this oxidation state of Sc is also indicated by the eight-line EPR spectra arising from the I=7/2 45 Sc nucleus. The Sc(NR 2 ) 3 reduction differs from Ln(NR 2 ) 3 reactions (Ln=Y and lanthanides) in that it occurs under N 2 without formation of isolable reduced dinitrogen species. [K(18-c-6)][Sc(NR 2 ) 3 ] reacts with CO 2 to produce an oxalate complex, {K 2 (18-c-6) 3 }{[(R 2 N) 3 Sc] 2 (μ-C 2 O 4 -κ 1 O:κ 1 O'')}, and a CO 2 - radical anion complex, [(R 2 N) 3 Sc(μ-OCO-κ 1 O:κ 1 O')K(18-c-6)] n . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biophysical controls on light response of net CO2 exchange in a winter wheat field in the North China Plain.

Directory of Open Access Journals (Sweden)

Xiaojuan Tong

Full Text Available To investigate the impacts of biophysical factors on light response of net ecosystem exchange (NEE, CO2 flux was measured using the eddy covariance technique in a winter wheat field in the North China Plain from 2003 to 2006. A rectangular hyperbolic function was used to describe NEE light response. Maximum photosynthetic capacity (P max was 46.6 ± 4.0 µmol CO2 m(-2 s(-1 and initial light use efficiency (α 0.059 ± 0.006 µmol µmol(-1 in April-May, two or three times as high as those in March. Stepwise multiple linear regressions showed that P max increased with the increase in leaf area index (LAI, canopy conductance (g c and air temperature (T a but declined with increasing vapor pressure deficit (VPD (P25°C or VPD>1.1-1.3 kPa, NEE residual increased with the increase in T a and VPD (P<0.001, indicating that temperature and water stress occurred. When g c was more than 14 mm s(-1 in March and May and 26 mm s(-1 in April, the NEE residuals decline disappeared, or even turned into an increase in g c (P<0.01, implying shifts from stomatal limitation to non-stomatal limitation on NEE. Although the differences between sunny and cloudy sky conditions were unremarkable for light response parameters, simulated net CO2 uptake under the same radiation intensity averaged 18% higher in cloudy days than in sunny days during the year 2003-2006. It is necessary to include these effects in relevant carbon cycle models to improve our estimation of carbon balance at regional and global scales.

Thermogravimetric, Calorimetric, and Structural Studies of the Co3 O4 /CoO Oxidation/Reduction Reaction

Science.gov (United States)

Unruh, Karl; Cichocki, Ronald; Kelly, Brian; Poirier, Gerald

2015-03-01

To better assess the potential of cobalt oxide for thermal energy storage (TES), the Co3O4/CoO oxidation/reduction reaction has been studied by thermogravimetric (TGA), calorimetric (DSC), and x-ray diffraction (XRD) measurements in N2 and atmospheric air environments. TGA measurements showed an abrupt mass loss of about 6.6% in both N2 and air, consistent with the stoichiometric reduction of Co3O4 to CoO and structural measurements. The onset temperature of the reduction of Co3O4 in air was only weakly dependent on the sample heating rate and occurred at about 910 °C. The onset temperature for the oxidation of CoO varied between about 850 and 875 °C for cooling rates between 1 and 20 °C/min, but complete re-conversion to Co3O4 could only be achieved at the slowest cooling rates. Due to the dependence of the rate constant on the oxygen partial pressure, the oxidation of Co3O4 in a N2 environment occurred at temperatures between about 775 and 825 °C for heating rates between 1 and 20 °C/min and no subsequent re-oxidation of the reduced Co3O4 was observed on cooling to room temperature. In conjunction with a measured transition heat of about 600 J/g of Co3O4, these measurements indicate that cobalt oxide is a viable TES material.

Microbial reduction of [Co(III)–EDTA]{sup −} by Bacillus licheniformis SPB-2 strain isolated from a solar salt pan

Energy Technology Data Exchange (ETDEWEB)

Paraneeiswaran, Arunachalam [Departartment of Biotechnology, Pondicherry University, Puducherry (India); Shukla, Sudhir K. [Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603102 (India); Homi Bhabha National Institute, Mumbai 400094 (India); Prashanth, K. [Departartment of Biotechnology, Pondicherry University, Puducherry (India); Rao, T. Subba, E-mail: subbarao@igcar.gov.in [Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603102 (India); Homi Bhabha National Institute, Mumbai 400094 (India)

2015-02-11

Graphical abstract: - Highlights: • Bacillus licheniformis SPB-2 was used in the bioremediation of [Co(III)–EDTA]{sup −}. • The bacterial biomass adsorbed the Co–EDTA complex after its reduction. • [Co(III)–EDTA]{sup −} complex showed Bacillus spore inducing property. • B. licheniformis SPB-2 showed significantly radio-tolerance (D{sub 10} = 250 Gy). - Abstract: Naturally stressed habitats are known to be repositories for novel microorganisms with potential bioremediation applications. In this study, we isolated a [Co(III)–EDTA]{sup −} reducing bacterium Bacillus licheniformis SPB-2 from a solar salt pan that is exposed to constant cycles of hydration and desiccation in nature. [Co(III)–EDTA]{sup −} generated during nuclear waste management process is difficult to remove from the waste due to its high stability and solubility. It is reduced form i.e. [Co(II)–EDTA]{sup 2−} is less stable though it is toxic. This study showed that B. licheniformis SPB-2 reduced 1 mM [Co(III)–EDTA]{sup −} in 14 days when grown in a batch mode. However, subsequent cycles showed an increase in the reduction activity, which was observed up to four cycles. Interestingly, the present study also showed that [Co(III)–EDTA]{sup −} acted as an inducer for B. licheniformis SPB-2 spore germination. Vegetative cells germinated from the spores were found to be involved in [Co(III)–EDTA]{sup −} reduction. More detailed investigations showed that after [Co(III)–EDTA]{sup −} reduction, i.e. [Co(II)–EDTA]{sup 2−} complex was removed by B. licheniformis SPB-2 from the bulk liquid by adsorption phenomenon. The bacterium showed a D{sub 10} value (radiation dose required to kill 90% cells) of ∼250 Gray (Gy), which signifies the potential use of B. licheniformis SPB-2 for bioremediation of moderately active nuclear waste.

NHC-Ag/Pd-Catalyzed Reductive Carboxylation of Terminal Alkynes with CO2 and H2 : A Combined Experimental and Computational Study for Fine-Tuned Selectivity.

Science.gov (United States)

Yu, Dingyi; Zhou, Feng; Lim, Diane S W; Su, Haibin; Zhang, Yugen

2017-03-09

Reductive carboxylation of terminal alkynes utilizing CO 2 and H 2 as reactants is an interesting and challenging transformation. Theoretical calculations indicated it would be kinetically possible to obtain cinnamic acid, the reductive carboxylation product, from phenylacetylene in a CO 2 /H 2 system with an N-heterocyclic carbene (NHC)-supported Ag/Pd bimetallic catalysts through competitive carboxylation/hydrogenation cascade reactions in one step. These calculations were verified experimentally with a poly-NHC-supported Ag/Pd catalyst. By tuning the catalyst composition and reaction temperature, phenylacetylene was selectively converted to cinnamic acid, hydrocinnamic acid, or phenylpropiolic acid in excellent yields. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

CO{sub 2} separation from exhaust gas; CO{sub 2} separasjon fra eksosgass

Energy Technology Data Exchange (ETDEWEB)

Magelssen, Paul Fr. [Saga Petroleum A/S, Forus (Norway)

1998-07-01

When Saga wanted to reduce the CO{sub 2} emissions from Snorre B, cleaning of CO{sub 2} from exhaust gas was one of several options considered. CO{sub 2} cleaning using membrane/amine technology is under development. Saga required that the technology should be qualified and that the yield of the Snorre B project should not be reduced. This presentation discusses qualification of combined membrane/amine technology, environmental issues, economic issues and implementation on the Snorre B platform. Flue gas from the gas turbine is passed to a CO{sub 2} absorption and desorption stage from which the CO{sub 2} is passed on for compression and disposal while the cleaned flue is let out. The membrane is situated between the flue gas and the absorbent liquid. The pores are large enough for the CO{sub 2} to pass through quickly and small enough to prevent the liquid from penetrating into the pores. The packing factor is high, 500 - 1000 m2/m3, there is no formation of froth, ducts or entrainment of the liquid. New technology implies 65 - 70% size reduction of the main equipment and 39 - 40% reduction of the energy consumption. Research on amines brings out new chemicals which imply 80% reduction in the consumption of chemicals and the quantity of special waste produced. If a CO{sub 2} cleaning plant is installed on a LM 2500, the CO{sub 2} emissions can be reduced by 97,200 ton/year given the right operational conditions. Although it was decided in 1998 not to install the module with the CO{sub 2} pilot cleaning plant, Snorre B is still a good environmental project having CO{sub 2} emission within the values set by Miljoesok.

In-Situ XRD during Electrochemical CO Reduction on Cu

DEFF Research Database (Denmark)

Bertheussen, Erlend; Scott, Søren Bertelsen; Hogg, Thomas

2018-01-01

Almost all-successful CO2 and CO reduction catalysts to higher chain carbons are based on copper1, however various facets and pre-treatments of copper have shown to give a wide variety of product selectivity.2,3 Currently there are many unanswered questions regarding active sites and mechanisms t...

Energy efficiency and reduction of CO2 emissions from campsites management in a protected area.

Science.gov (United States)

Del Moretto, Deny; Branca, Teresa Annunziata; Colla, Valentina

2018-06-02

Campsites can be a pollution source, mainly due to the energy consumption. In addition, the green areas, thanks to the direct CO 2 sequestration and the shading, indirectly prevent the CO 2 emissions related to energy consumption. The methodology presented in this paper allowed assessing the annual CO 2 emissions directly related to the campsite management and the consequent environmental impact in campsite clusters in Tuscany. The software i-Tree Canopy was exploited, enabling to evaluate in terms of "canopy" the tonnes of CO 2 sequestered by the vegetation within each campsite. Energy and water consumptions from 2012 to 2015 were assessed for each campsite. As far as the distribution of sequestered CO 2 is concerned, the campsites ranking was in accordance to their size. According to the indicator "T-Tree" or canopy cover, a larger area of the canopy cover allows using less outdoor areas covered by trees for the sequestration of the remaining amount of pollutants. The analysis shows that the considered campsites, that are located in a highly naturalistic Park, present significant positive aspects both in terms of CO 2 emission reductions and of energy efficiency. However, significant margins of improvement are also possible and they were analysed in the paper. Copyright © 2018 Elsevier Ltd. All rights reserved.

Recent Advances in Transition-Metal-Mediated Electrocatalytic CO2 Reduction: From Homogeneous to Heterogeneous Systems

Directory of Open Access Journals (Sweden)

Da-Ming Feng

2017-12-01

Full Text Available Global climate change and increasing demands for clean energy have brought intensive interest in the search for proper electrocatalysts in order to reduce carbon dioxide (CO2 to higher value carbon products such as hydrocarbons. Recently, transition-metal-centered molecules or organic frameworks have been reported to show outstanding electrocatalytic activity in the liquid phase. Their d-orbital electrons are believed to be one of the key factors to capture and convert CO2 molecules to value-added low-carbon fuels. In this review, recent advances in electrocatalytic CO2 reduction have been summarized based on the targeted products, ranging from homogeneous reactions to heterogeneous ones. Their advantages and fallbacks have been pointed out and the existing challenges, especially with respect to the practical and industrial application are addressed.

Recent Advances in Transition-Metal-Mediated Electrocatalytic CO2 Reduction: From Homogeneous to Heterogeneous Systems

KAUST Repository

Feng, Da-Ming

2017-12-01

Global climate change and increasing demands for clean energy have brought intensive interest in the search for proper electrocatalysts in order to reduce carbon dioxide (CO2) to higher value carbon products such as hydrocarbons. Recently, transition-metal-centered molecules or organic frameworks have been reported to show outstanding electrocatalytic activity in the liquid phase. Their d-orbital electrons are believed to be one of the key factors to capture and convert CO2 molecules to value-added low-carbon fuels. In this review, recent advances in electrocatalytic CO2 reduction have been summarized based on the targeted products, ranging from homogeneous reactions to heterogeneous ones. Their advantages and fallbacks have been pointed out and the existing challenges, especially with respect to the practical and industrial application are addressed.

Nature and Distribution of Stable Subsurface Oxygen in Copper Electrodes During Electrochemical CO2 Reduction

DEFF Research Database (Denmark)

Cavalca, Filippo Carlo; Ferragut, Rafael; Aghion, Stefano

2017-01-01

Oxide-derived copper (OD-Cu) electrodes exhibit higher activity than pristine copper during the carbon dioxide reduction reaction (CO2RR) and higher selectivity towards ethylene. The presence of residual subsurface oxygen in OD-Cu has been proposed to be responsible for such improvements, although...

CoPt nanoparticles by chemical reduction

International Nuclear Information System (INIS)

Wang, H.L.; Zhang, Y.; Huang, Y.; Zeng, Q.; Hadjipanayis, G.C.

2004-01-01

CoPt nanoparticles with a size of 1-2 nm were synthesized by chemical reduction using the solvents of water and alcohol. A phase transformation from the originally disordered face centered cubic (FCC) structure to an ordered face centered tetragonal L1 0 structure occurred after annealing, which results in the coercivity up to 9 kOe because of the high anisotropy of the tetragonal phase (K∼2-4x10 7 erg/cm 3 ) (Philos. Mag. 13 (1966) 567; IEEE Trans. Magn. 20 (1984) 1625). HREM images of as-grow Co 48 Pt 52 shows the single-crystalline FCC structure with the shape of columnar and spherical

Reduction of lumichrome by the radical anions of CO2 and lipoamide

International Nuclear Information System (INIS)

Ahmad, R.; Armstrong, D.A.

1984-01-01

The uptake of reducing equivalents of .CO 2 - by lumichrome in spectrophotometric titrations has been re-examined in the light of a recently reported extinction coefficient of 10 500 M -1 cm -1 at pH 6, which is in agreement with 10 270 +- 100 M -1 cm -1 determined here. The average uptake was 1.8 +- 0.1, independent of pH in the range 6.3-9.0. The major product appears to be a dihydro-alloxazine, which can be reoxidized quantitatively to lumichrome by .Br 2 - radicals or by O 2 . As in the case of dihydroflavins, oxidation by O 2 is biphasic. As in the case of flavins, a two electron reduction of lumichrome was also observed with the disulphide monoanion of lipoamide (LS. 2 - ), but that reduction does not go to 100 per cent yield. Contrary to our earlier conclusions, which were based on an erroneous extinction coefficient, the combination of lumichrome radicals (2.LcH→HLc-LcH) was of relatively little (< approx. 20 per cent) importance, and the behaviour of lumichrome on treatment with reducing species was rather similar to that of flavins. (author)

Preparation of Cu2O modified TiO2 nanopowder and its application to the visible light photoelectrocatalytic reduction of CO2 to CH3OH

Science.gov (United States)

Li, Bin; Niu, Wenchao; Cheng, Yongwei; Gu, Junjie; Ning, Ping; Guan, Qingqing

2018-05-01

Cu2O/TiO2 nanopowders were prepared and used as thin film electrode raw materials for CO2 photoelectroreduction. Characterization results from XRD, TEM, UV-Vis and BET show that Cu2O/TiO2 composites have regular morphology, narrow band gap, excellent textural properties, and exhibits marked response of visible light. The photoelectrocatalytic results show that CO2 can be reduced to formaldehyde (i.e., intermediate) and finally methanol (i.e., end product). In addition, the CO2 photoelectroreduction pathway and the mechanism of photoelectrocatalysis are discussed. In summary, the work reports a potential method of CO2 reduction by visible-light photocatalysis without an external bias.

Unusual Co moment reduction in the NiCoO/Co exchange bias system

Energy Technology Data Exchange (ETDEWEB)

Brueck, S. [Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart (Germany)]. E-mail: brueck@mf.mpg.de; Goering, E. [Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Tang, Y.J. [Center for Magnetic Recording Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0401 (United States); Schuetz, G. [Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Berkowitz, A.E. [Center for Magnetic Recording Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0401 (United States); Department of Physics, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0401 (United States)

2007-03-15

To answer the question on how the explicit mechanism of coupling in the antiferromagnetic alloy NiCoO is established when in close contact to a ferromagnetic Co layer, X-ray magnetic circular dichroism (XMCD) measurements have been performed. Precise XMCD spectra at the L{sub 2,3}-edge of Ni as well as Co have been obtained at room temperature and at 80K by measuring total electron yield X-ray absorption spectra. The Ni XMCD clearly shows the existence of free, rotatable magnetic Ni moments in the antiferromagnet. As for the Co, XMCD at room temperature shows an average magnetic moment comparable to bulk values. Cooling the sample to 80K decreases the average Co moment by 10%. This decrease is explained by a reduction of ferromagnetic cobalt moments related to antiferromagnetic coupling or pinning close to the interface.

The public perspective of carbon capture and storage for CO2 emission reductions in China

International Nuclear Information System (INIS)

Duan Hongxia

2010-01-01

To explore public awareness of carbon capture and storage (CCS), attitudes towards the use of CCS and the determinants of CCS acceptance in China, a study was conducted in July 2009 based on face-to-face interviews with participants across the country. The result showed that the awareness of CCS was low among the surveyed public in China, compared to other clean energy technologies. Respondents indicated a slightly supportive attitude towards the use of CCS as an alternative technology to CO 2 emission reductions. The regression model revealed that in addition to CCS knowledge, respondents' understanding of the characteristics of CCS, such as the maturity of the technology, risks, capability of CO2 emission reductions, and CCS policy were all significant factors in predicting the acceptance of CCS. The findings suggest that integrating public education and communication into CCS development policy would be an effective strategy to overcome the barrier of low public acceptance.

Rechargeable Al-CO2 Batteries for Reversible Utilization of CO2.

Science.gov (United States)

Ma, Wenqing; Liu, Xizheng; Li, Chao; Yin, Huiming; Xi, Wei; Liu, Ruirui; He, Guang; Zhao, Xian; Luo, Jun; Ding, Yi

2018-05-21

The excessive emission of CO 2 and the energy crisis are two major issues facing humanity. Thus, the electrochemical reduction of CO 2 and its utilization in metal-CO 2 batteries have attracted wide attention because the batteries can simultaneously accelerate CO 2 fixation/utilization and energy storage/release. Here, rechargeable Al-CO 2 batteries are proposed and realized, which use chemically stable Al as the anode. The batteries display small discharge/charge voltage gaps down to 0.091 V and high energy efficiencies up to 87.7%, indicating an efficient battery performance. Their chemical reaction mechanism to produce the performance is revealed to be 4Al + 9CO 2 ↔ 2Al 2 (CO 3 ) 3 + 3C, by which CO 2 is reversibly utilized. These batteries are envisaged to effectively and safely serve as a potential CO 2 fixation/utilization strategy with stable Al. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coal-based synthetic natural gas (SNG): A solution to China’s energy security and CO2 reduction?

International Nuclear Information System (INIS)

Ding, Yanjun; Han, Weijian; Chai, Qinhu; Yang, Shuhong; Shen, Wei

2013-01-01

Considering natural gas (NG) to be the most promising low-carbon option for the energy industry, large state owned companies in China have established numerous coal-based synthetic natural gas (SNG) projects. The objective of this paper is to use a system approach to evaluate coal-derived SNG in terms of life-cycle energy efficiency and CO 2 emissions. This project examined main applications of the SNG and developed a model that can be used for evaluating energy efficiency and CO 2 emissions of various fuel pathway systems. The model development started with the GREET model, and added the SNG module and an end-use equipment module. The database was constructed with Chinese data. The analyses show when the SNG are used for cooking, power generation, steam production for heating and industry, life-cycle energies are 20–108% higher than all competitive pathways, with a similar rate of increase in life-cycle CO 2 emissions. When a compressed natural gas (CNG) car uses the SNG, life-cycle CO 2 emission will increase by 150–190% compared to the baseline gasoline car and by 140–210% compared to an electric car powered by electricity from coal-fired power plants. The life-cycle CO 2 emission of SNG-powered city bus will be 220–270% higher than that of traditional diesel city bus. The gap between SNG-powered buses and new hybrid diesel buses will be even larger—life-cycle CO 2 emission of the former being around 4 times of that of the latter. It is concluded that the SNG will not accomplish the tasks of both energy conservation and CO 2 reduction. - Highlights: ► We evaluated life-cycle energy efficiency and CO 2 emissions of coal-derived SNG. ► We used GREET model and added a coal-based SNG and an end-use modules. ► The database was constructed with Chinese domestic data. ► Life-cycle energies and CO 2 emissions of coal-based SNG are 20–100% higher. ► Coal-based SNG is not a solution to both energy conservation and CO 2 reduction

Impacts of potential CO2-reduction policies on air quality in the United States.

Science.gov (United States)

Trail, Marcus A; Tsimpidi, Alexandra P; Liu, Peng; Tsigaridis, Kostas; Hu, Yongtao; Rudokas, Jason R; Miller, Paul J; Nenes, Athanasios; Russell, Armistead G

2015-04-21

Impacts of emissions changes from four potential U.S. CO2 emission reduction policies on 2050 air quality are analyzed using the community multiscale air quality model (CMAQ). Future meteorology was downscaled from the Goddard Institute for Space Studies (GISS) ModelE General Circulation Model (GCM) to the regional scale using the Weather Research Forecasting (WRF) model. We use emissions growth factors from the EPAUS9r MARKAL model to project emissions inventories for two climate tax scenarios, a combined transportation and energy scenario, a biomass energy scenario and a reference case. Implementation of a relatively aggressive carbon tax leads to improved PM2.5 air quality compared to the reference case as incentives increase for facilities to install flue-gas desulfurization (FGD) and carbon capture and sequestration (CCS) technologies. However, less capital is available to install NOX reduction technologies, resulting in an O3 increase. A policy aimed at reducing CO2 from the transportation sector and electricity production sectors leads to reduced emissions of mobile source NOX, thus reducing O3. Over most of the U.S., this scenario leads to reduced PM2.5 concentrations. However, increased primary PM2.5 emissions associated with fuel switching in the residential and industrial sectors leads to increased organic matter (OM) and PM2.5 in some cities.

Unlocking the Electrocatalytic Activity of Antimony for CO2 Reduction by Two-Dimensional Engineering of the Bulk Material.

Science.gov (United States)

Li, Fengwang; Xue, Mianqi; Li, Jiezhen; Ma, Xinlei; Chen, Lu; Zhang, Xueji; MacFarlane, Douglas R; Zhang, Jie

2017-11-13

Two-dimensional (2D) materials are known to be useful in catalysis. Engineering 3D bulk materials into the 2D form can enhance the exposure of the active edge sites, which are believed to be the origin of the high catalytic activity. Reported herein is the production of 2D "few-layer" antimony (Sb) nanosheets by cathodic exfoliation. Application of this 2D engineering method turns Sb, an inactive material for CO 2 reduction in its bulk form, into an active 2D electrocatalyst for reduction of CO 2 to formate with high efficiency. The high activity is attributed to the exposure of a large number of catalytically active edge sites. Moreover, this cathodic exfoliation process can be coupled with the anodic exfoliation of graphite in a single-compartment cell for in situ production of a few-layer Sb nanosheets and graphene composite. The observed increased activity of this composite is attributed to the strong electronic interaction between graphene and Sb. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimized retrofitting in order to mobilize CO{sub 2} reduction potentials in existing residential buildings; Umfassende Mobilisierung von CO{sub 2}-Reduktionspotentialen im Wohngebaeudebestand durch optimierte Altbausanierung

Energy Technology Data Exchange (ETDEWEB)

Goerg, M. [Stadtwerke Hannover AG (Germany)

1995-03-01

The article describes the exploitation of CO{sub 2} reduction potentials as of problem of social innovation. The possibilities and limits of new services such as heat service and conservation contracting are gone into. The necessity of investment support is explained and a financing concept is presented. (orig.) [Deutsch] Der Beitrag beschreibt die Erschliessung der CO{sub 2}-Reduktionspotentiale als ein Problem gesellschaftlicher Innovation. Dargestellt werden Moeglichkeiten und Grenzen neuer Dienstleistungsangebote wie Waermeservice und Einspar-Contracting. Die Notwendigkeit einer Investitionsfoerderung wird begruendet und eine Finanzierungsidee vorgestellt. (orig.)

Fiscal 1996 survey of potential international cooperation for a long-term scenario on CO2 reduction; 1996 nendo CO2 sakugen ni kakawaru choki shinario ni kansuru kokusai kyoryoku kanosei chosa

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

For the purpose of working out a CO2 reduction scenario and a CO2 policy introduction scenario, a survey was conducted of comparisons between ten and several models which are world-known and models of the New Earth 21, potential international cooperation to be carried out in the future, etc. The survey included organizations which are developing CO2 policy evaluation models, survey reports made in the past, details of literature for the analysis and arrangement. From the result, details of the questionnaire survey and organizations to be surveyed were decided on for the questionnaire survey. Objects for the survey were 7 countries and 22 organizations, and survey items were places for information exchange, sending/receiving of researchers, exchange of input data, comparative calculation based on the common database, joint research work, economy, the carbon tax, impact, renewable energy, how to handle and think of the carbon isolation, etc. As a result of the survey, proposed were a workshop on CO2 reduction, a comparative study of simulation models, etc. 25 refs., 50 figs., 12 tabs.

Metal-Organic Framework-Stabilized CO2/Water Interfacial Route for Photocatalytic CO2 Conversion.

Science.gov (United States)

Luo, Tian; Zhang, Jianling; Li, Wei; He, Zhenhong; Sun, Xiaofu; Shi, Jinbiao; Shao, Dan; Zhang, Bingxing; Tan, Xiuniang; Han, Buxing

2017-11-29

Here, we propose a CO 2 /water interfacial route for photocatalytic CO 2 conversion by utilizing a metal-organic framework (MOF) as both an emulsifier and a catalyst. The CO 2 reduction occurring at the CO 2 /water interface produces formate with remarkably enhanced efficiency as compared with that in conventional solvent. The route is efficient, facile, adjustable, and environmentally benign, which is applicable for the CO 2 transformation photocatalyzed by different kinds of MOFs.

Factors influencing CO2 emissions in China's power industry: Co-integration analysis

International Nuclear Information System (INIS)

Zhao, Xiaoli; Ma, Qian; Yang, Rui

2013-01-01

More than 40% of China's total CO 2 emissions originate from the power industry. The realization of energy saving and emission reduction within China's power industry is therefore crucial in order to achieve CO 2 emissions reduction in this country. This paper applies the autoregressive-distributed lag (ARDL) co-integration model to study the major factors which have influenced CO 2 emissions within China's power industry from 1980 to 2010. Results have shown that CO 2 emissions from China's power industry have been increasing rapidly. From 1980 to 2010, the average annual growth rate was 8.5%, and the average growth rate since 2002 has amounted to 10.5%. Secondly, the equipment utilization hour (as an indicator of the power demand) has the greatest influence on CO 2 emissions within China's power industry. In addition, the impact of the industrial added value of the power sector on CO 2 emissions is also positive from a short-term perspective. Thirdly, the Granger causality results imply that one of the important motivators behind China's technological progress, within the power industry, originates from the pressures created by a desire for CO 2 emissions reduction. Finally, this paper provides policy recommendations for energy saving and emission reduction for China's power industry. - Highlights: ► We study the major factors influencing China's power industry CO 2 emissions. ► The average annual growth rate of CO 2 emission from power industry is calculated. ► Installed capacity has the greatest influence on power industry CO 2 emission. ► The Granger causality between CO 2 emission and its effecting factors is analyzed

Identifying Different Types of Catalysts for CO2 Reduction by Ethane through Dry Reforming and Oxidative Dehydrogenation.

Science.gov (United States)

Porosoff, Marc D; Myint, Myat Noe Zin; Kattel, Shyam; Xie, Zhenhua; Gomez, Elaine; Liu, Ping; Chen, Jingguang G

2015-12-14

The recent shale gas boom combined with the requirement to reduce atmospheric CO2 have created an opportunity for using both raw materials (shale gas and CO2 ) in a single process. Shale gas is primarily made up of methane, but ethane comprises about 10 % and reserves are underutilized. Two routes have been investigated by combining ethane decomposition with CO2 reduction to produce products of higher value. The first reaction is ethane dry reforming which produces synthesis gas (CO+H2 ). The second route is oxidative dehydrogenation which produces ethylene using CO2 as a soft oxidant. The results of this study indicate that the Pt/CeO2 catalyst shows promise for the production of synthesis gas, while Mo2 C-based materials preserve the CC bond of ethane to produce ethylene. These findings are supported by density functional theory (DFT) calculations and X-ray absorption near-edge spectroscopy (XANES) characterization of the catalysts under in situ reaction conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Throwing new light on the reduction of CO2.

Science.gov (United States)

Ozin, Geoffrey A

2015-03-18

While the chemical energy in fossil fuels has enabled the rapid rise of modern civilization, their utilization and accompanying anthropogenic CO2 emissions is occurring at a rate that is outpacing nature's carbon cycle. Its effect is now considered to be irreversible and this could lead to the demise of human society. This is a complex issue without a single solution, yet from the burgeoning global research activity and development in the field of CO2 capture and utilization, there is light at the end of the tunnel. In this article a couple of recent advances are illuminated. Attention is focused on the discovery of gas-phase, light-assisted heterogeneous catalytic materials and processes for CO2 photoreduction that operate at sufficiently high rates and conversion efficiencies, and under mild conditions, to open a new pathway for an energy transition from today's "fossil fuel economy" to a new and sustainable "CO2 economy". Whichever of the competing CO2 capture and utilization approaches proves to be the best way forward for the development of a future CO2-based solar fuels economy, hopefully this can occur in a period short enough to circumvent the predicted adverse consequences of greenhouse gas climate change. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scenario analysis of energy saving and CO_2 emissions reduction potentials to ratchet up Japanese mitigation target in 2030 in the residential sector

International Nuclear Information System (INIS)

Wakiyama, Takako; Kuramochi, Takeshi

2017-01-01

This paper assesses to what extent CO_2 emissions from electricity in the residential sector can be further reduced in Japan beyond its post-2020 mitigation target (known as “Intended Nationally Determined Contribution (INDC)”). The paper examines the reduction potential of electricity demand and CO_2 emissions in the residential sector by conducting a scenario analysis. Electricity consumption scenarios are set up using a time-series regression model, and used to forecast the electricity consumption patterns to 2030. The scenario analysis also includes scenarios that reduce electricity consumption through enhanced energy efficiency and energy saving measures. The obtained results show that Japan can reduce electricity consumption and CO_2 emissions in the residential sector in 2030 more than the Japanese post-2020 mitigation target indicates. At the maximum, the electricity consumption could be reduced by 35 TWh, which contributes to 55.4 MtCO_2 of emissions reduction in 2030 compared to 2013 if the voluntarily targeted CO_2 intensity of electricity is achieved. The result implies that Japan has the potential to ratchet up post-2020 mitigation targets discussed under the Paris Agreement of the United Nations Framework Convention on Climate Change (UNFCCC). - Highlights: • Further reduction of electricity consumption is possible beyond Japan's post-2020 mitigation target. • Energy saving efforts by households and incentives to reduce electricity demands are required. • Improvement of CO_2 intensity from electricity is a key factor in the reduction of CO_2 emissions.

Carbon-doped boron nitride nanosheet as a promising catalyst for N2O reduction by CO or SO2 molecule: A comparative DFT study

Science.gov (United States)

Esrafili, Mehdi D.; Saeidi, Nasibeh

2018-06-01

We report for the first time, the catalytic activity of the experimentally available carbon-doped boron nitride nanosheet (C-BNNS) towards the reduction of N2O in the presence of CO or SO2 molecule. According to our density functional theory calculations, C-doping can introduce high spin density into BN monolayer which is mainly localized over the C and its neighboring N atoms. The Hirshfeld charge density analysis reveals that the electron-rich C-BNNS acts as an electron donating support to activate N2O molecule which is an important step in the reduction of N2O. The N2O reduction reaction starts with the dissociative adsorption of N2O over the C-BNNS surface, yielding the N2 molecule and an activated oxygen moiety (Oads) adsorbed over the C atom. The reaction then proceeds via the elimination of Oads by a CO or SO2 molecule. The obtained low activation energies clearly indicate that the metal-free C-BNNS surface can be regarded as a highly active catalyst for the reduction of N2O. The results of this study may open new avenues in searching low cost and highly active BN-based catalysts for low temperature reduction of N2O.

Possibilities for the reduction of CO2- and CH4-emissions of natural gas

International Nuclear Information System (INIS)

Muessig, S.

1994-01-01

The use of fossil fuels increases the portion of greenhouse gases, especially CO 2 and CH 4 . In this paper firstly the specific emission rates of these greenhouse gases for the various fuels are compared. Secondly possibilities for the reduction of CO 2 and CH 4 for natural gas which are relatively small anyhow are discussed. Thirdly the use of renewable energy within the gas industry and the ocean and into depleted reservoirs are discussed. It is shown that the efficient use of energy of the fossil fuel natural gas is most successful in all branches of gas consumption to decrease emission. Combined-cycle processes, cogeneration as well as modern domestic heating systems are described. Fuel cells and the application of hydrogen is shortly discussed. (orig.)

CO2-induced pH reduction increases physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus

Science.gov (United States)

Hu, Menghong; Lin, Daohui; Shang, Yueyong; Hu, Yi; Lu, Weiqun; Huang, Xizhi; Ning, Ke; Chen, Yimin; Wang, Youji

2017-01-01

The increasing usage of nanoparticles has caused their considerable release into the aquatic environment. Meanwhile, anthropogenic CO2 emissions have caused a reduction of seawater pH. However, their combined effects on marine species have not been experimentally evaluated. This study estimated the physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus under high pCO2 (2500-2600 μatm). We found that respiration rate (RR), food absorption efficiency (AE), clearance rate (CR), scope for growth (SFG) and O:N ratio were significantly reduced by nano-TiO2, whereas faecal organic weight rate and ammonia excretion rate (ER) were increased under nano-TiO2 conditions. High pCO2 exerted lower effects on CR, RR, ER and O:N ratio than nano-TiO2. Despite this, significant interactions of CO2-induced pH change and nano-TiO2 were found in RR, ER and O:N ratio. PCA showed close relationships among most test parameters, i.e., RR, CR, AE, SFG and O:N ratio. The normal physiological responses were strongly correlated to a positive SFG with normal pH and no/low nano-TiO2 conditions. Our results indicate that physiological functions of M. coruscus are more severely impaired by the combination of nano-TiO2 and high pCO2.

Review of CO2 Reduction Technologies using Mineral Carbonation of Iron and Steel Making Slag in Malaysia

Science.gov (United States)

Norhana Selamat, Siti; Nor, Nik Hisyamudin Muhd; Rashid, Muhammad Hanif Abdul; Fauzi Ahmad, Mohd; Mohamad, Fariza; Ismail, Al Emran; Fahrul Hassan, Mohd; Turan, Faiz Mohd; Zain, Mohd Zamzuri Mohd; Abu Bakar, Elmi; Seiji, Yokoyama

2017-10-01

Climate change, greenhouse gas effect, and global warming is envisioning to turn more awful and more terrible by year. Since the leading cause of global warming is uncontrolled CO2 in atmosphere. The amount of unused steel slag is expected to increment later on, steel industries is one of the mechanical industries that contribute the CO2 emission. That because this businesses deliver carbon in light of powers reductant and substantial volume of steel. The changes of atmosphere these day is truly developing concern and that make steel creator are confronted with test of discovering methods for bringing down CO2 emission. Malaysia is working decidedly in the diminishment of CO2 gas. There are a few techniques in decreasing the amount of CO2 in the air as underlined by the Intergovernmental Panel of Climate Change (IPCC), an organization under the United Country however CCS is an extremely encouraging innovation to moderate CO2 emission in air. Mineral carbonation is another technique to store carbon dioxide permanently, long term stability and vast capacity.

Technology priorities for transport in Asia: assessment of economy-wide CO2 emissions reduction for Lebanon

DEFF Research Database (Denmark)

Dhar, Subash; Marpaung, Charles O. P.

2015-01-01

mitigations actions (NAMA) given their strong contribution for development and therefore a methodology based on in-put out-put decomposition analysis is proposed for analysing economy wide CO2 emissions reductions. The methodology has been applied for the transport sector of Lebanon where alternative fuels...... of technologies and availability of technology characteristics. Non-motorized transport, mass transit and technologies that improve vehicle energy efficiency emerged as the three most preferred technology choices for the countries. These technology choices can be appropriate candidates for nationally appropriate......,improvement to cars (private and taxis) and buses for public transport were prioritized by stakeholders. The economy-wide CO2 emission reduce by 2,269 thousand tons by 2020 if the prioritized technologies are implemented in Lebanon. Fuel mix effect and structural effect would reduce CO2 emission by 2,611 thousand...

Assessment of Energy Efficiency Improvement and CO₂ Emission Reduction Potentials in the Cement Industry in China

Energy Technology Data Exchange (ETDEWEB)

Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Morrow, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Masanet, Eric [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sathaye, Jayant [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Xu, Tengfang [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-06-15

China’s annual cement production (i.e., 1,868 Mt) in 2010 accounted for nearly half of the world’s annual cement production in the same year. We identified and analyzed 23 energy efficiency technologies and measures applicable to the processes in the cement industry. The Conservation Supply Curve (CSC) used in this study is an analytical tool that captures both the engineering and the economic perspectives of energy conservation. Using a bottom-up electricity CSC model, the cumulative cost-effective electricity savings potential for the Chinese cement industry for 2010-2030 is estimated to be 251 TWh, and the total technical electricity saving potential is 279 TWh. The CO₂ emissions reduction associated with cost-effective electricity savings is 144 Mt CO₂ and the CO₂ emission reduction associated with technical electricity saving potential is 161 Mt CO₂. The fuel CSC model for the cement industry suggests cumulative cost-effective fuel savings potential of 4,326 PJ which is equivalent to the total technical potential with associated CO₂ emission reductions of 406 Mt CO₂. In addition, a sensitivity analysis with respect to the discount rate used is conducted to assess the effect of changes in this parameter on the results. We also developed a scenario in which instead of only implementing the international technologies in 2010-2030, we implement both international and Chinese domestic technologies during the analysis period and calculate the saving and cost of conserved energy accordingly. The result of this study gives a comprehensive and easy to understand perspective to the Chinese cement industry and policy makers about the energy efficiency potential and its associated cost.

Potential of plug-in hybrid electric vehicle for reduction of CO2 emission and role of non-fossil power plant

International Nuclear Information System (INIS)

Hiwatari, R.; Okano, K.; Yamamoto, H.

2009-01-01

A method to analyze the demand of electricity and the reduction of CO 2 emission and oil consumption by PHEV is established. Using the performance of PHEV optimized by EPRI and an estimation on the pattern of driving and charging in Japan, the following results are obtained. The electric demand for PHEV60(which has 60mile EV range) and PHEV20(which has 20mile EV range) is evaluated at 79.3 billion kWh and 41.2 billion kWh, respectively, in case that all vehicles in Japan (80 million cars) would be replaced by PHEV. The load leveling effect on the Japanese grid, which is hypothetically considered as one electric grid system, is evaluated at about 30 million kW, in case that all vehicles in Japan are replaced by PHEV60 and charged in the midnight. However, when the charge of PHEVs starts in the evening, that effect is not obtained. The reduction of CO 2 emission results in 64 million ton by the averaged CO 2 emissions intensity (emissions per unit of user end electricity) in Japan, and 98 million ton by electricity from the non-fossil power plant such as nuclear energy or renewable one. Those values are equivalent to 25% and 38% of CO 2 emission from the transport sector in Japan in 2003. Hence, non-fossil power plant enhances the reduction of CO 2 emission by the PHEV introduction. (author)

Simultaneous reduction of NO2 and CO in a domestic unvented gas-fired convective heater

International Nuclear Information System (INIS)

Arai, N.; Kasugai, N. A.; Hasatani, M.; Ishibashi, N.

1989-01-01

A programme of industrial and university research has been carried out to develop a domestic, unvented gas-fired space-heater capable of the simultaneous reduction of NO 2 and CO. To this end, lean-burning convective heaters of two types have been devised, and their performance has been characterised on methane-air mixtures. One burner contains a vertical cylinder of stainless-steel wire mesh (Type A), and the other incorporates a heat-recirculating matrix and a horizontal plate of stainless-steel wire mesh (Type B). The results obtained under a wide range of equivalence ratios show that: - the emission characteristics for NO x and NO 2 in Type A were excellent over the entire equivalence ratio of 0.5 - 1.0, but the concentration of CO was always higher than the current informal guideline in Japan, in which CO/CO 2 -3 . - Type B displayed an optimum range of equivalence ratios to satisfy simultaneously every guideline for NO x ( 2 ( 2 . However, since the optimum range of equivalence ratio was limited to between 0.45 and 0.55, further effort should be devoted to the extension of this optimum range. (Author)

CO2 Reduction Assembly Prototype Using Microlith-Based Sabatier Reactor for Ground Demonstration

Science.gov (United States)

Junaedi, Christian; Hawley, Kyle; Walsh, Dennis; Roychoudhury, Subir; Abney, Morgan B.; Perry, Jay L.

2014-01-01

The utilization of CO2 to produce life support consumables, such as O2 and H2O, via the Sabatier reaction is an important aspect of NASA's cabin Atmosphere Revitalization System (ARS) and In-Situ Resource Utilization (ISRU) architectures for both low-earth orbit and long-term manned space missions. Carbon dioxide can be reacted with H2, obtained from the electrolysis of water, via Sabatier reaction to produce methane and H2O. Methane can be stored and utilized as propellant while H2O can be either stored or electrolyzed to produce oxygen and regain the hydrogen atoms. Depending on the application, O2 can be used to replenish the atmosphere in human-crewed missions or as an oxidant for robotic and return missions. Precision Combustion, Inc. (PCI), with support from NASA, has previously developed an efficient and compact Sabatier reactor based on its Microlith® catalytic technology and demonstrated the capability to achieve high CO2 conversion and CH4 selectivity (i.e., =90% of the thermodynamic equilibrium values) at high space velocities and low operating temperatures. This was made possible through the use of high-heat-transfer and high-surface-area Microlith catalytic substrates. Using this Sabatier reactor, PCI designed, developed, and demonstrated a stand-alone CO2 Reduction Assembly (CRA) test system for ground demonstration and performance validation. The Sabatier reactor was integrated with the necessary balance-of-plant components and controls system, allowing an automated, single "push-button" start-up and shutdown. Additionally, the versatility of the test system prototype was demonstrated by operating it under H2-rich (H2/CO2 of >4), stoichiometric (ratio of 4), and CO2-rich conditions (ratio of <4) without affecting its performance and meeting the equilibrium-predicted water recovery rates. In this paper, the development of the CRA test system for ground demonstration will be discussed. Additionally, the performance results from testing the system at

NOx reduction using amine reclaimer wastes (ARW) generated in post combustion CO2 capture

DEFF Research Database (Denmark)

Botheju, Deshai; Glarborg, Peter; Tokheim, Lars-Andre

2012-01-01

Amine reclaimer wastes (ARW) generated in CO2 capture processes demand suitable disposal means. Such wastes contain remaining amine, NH3 and other degradation compounds. This study investigated the potential of using ARW as a NOx reducing agent, under laboratory conditions in a flow reactor....../NO ratios (waste product, together with its demonstrated NOx reduction capability and its calorific value contribution, makes it attractive as an additive...

Use of glucose as reductant to recover Co from spent lithium ions batteries.

Science.gov (United States)

Meng, Qi; Zhang, Yingjie; Dong, Peng

2017-06-01

A hydrometallurgical leaching process has been developed for recovery of Co and Li from cathode material (LiCoO 2 ) collected from spent LIBs using a mix solution of glucose and phosphoric acid. The spent LiCoO 2 before and after leaching process are analyzed by scanning electron microscopy. A leaching rate of about 98% Co and nearly 100% Li is presented with 1.5mol/L phosphoric acid and 0.02mol/L glucose at 80°C in about 2h. During leaching process, glucose was oxidized into monocarboxylic acid with reduction of Co(III) to Co(II). Co in solution was recovered as Co-oxalate after leaching process. Using glucose as reductant to dissolve LiCoO 2 with chelating agent of phosphoric acid is achieved here. Copyright © 2017 Elsevier Ltd. All rights reserved.

Emissions of CO{sub 2} from road freight transport in London: Trends and policies for long run reductions

Energy Technology Data Exchange (ETDEWEB)

Zanni, Alberto M., E-mail: a.m.zanni@lboro.ac.u [Transport Studies Group, Department of Civil and Building Engineering, Loughborough University, LE11 3TU Loughborough (United Kingdom); Bristow, Abigail L., E-mail: a.l.bristow@lboro.ac.u [Transport Studies Group, Department of Civil and Building Engineering, Loughborough University, LE11 3TU Loughborough (United Kingdom)

2010-04-15

Freight transport has been receiving increasing attention in both literature and practice following the growing recognition of its importance in urban transport planning. This paper analyses historical and projected road freight CO{sub 2} emissions in the city of London and explores the potential mitigation effect of a set of freight transport policies and logistics solutions. Findings indicate a range of policies with potential to reduce emissions in the period up to 2050. However, this reduction would appear to only be capable of partly counterbalancing the projected increase in freight traffic. More profound behavioural measures therefore appear to be necessary for London's CO{sub 2} emissions reduction targets to be met.

Emissions of CO{sub 2} from road freight transport in London. Trends and policies for long run reductions

Energy Technology Data Exchange (ETDEWEB)

Zanni, Alberto M.; Bristow, Abigail L. [Transport Studies Group, Department of Civil and Building Engineering, Loughborough University, LE11 3TU Loughborough (United Kingdom)

2010-04-15

Freight transport has been receiving increasing attention in both literature and practice following the growing recognition of its importance in urban transport planning. This paper analyses historical and projected road freight CO{sub 2} emissions in the city of London and explores the potential mitigation effect of a set of freight transport policies and logistics solutions. Findings indicate a range of policies with potential to reduce emissions in the period up to 2050. However, this reduction would appear to only be capable of partly counterbalancing the projected increase in freight traffic. More profound behavioural measures therefore appear to be necessary for London's CO{sub 2} emissions reduction targets to be met. (author)

Highly efficient visible light photocatalytic reduction of CO2 to hydrocarbon fuels by Cu-nanoparticle decorated graphene oxide.

Science.gov (United States)

Shown, Indrajit; Hsu, Hsin-Cheng; Chang, Yu-Chung; Lin, Chang-Hui; Roy, Pradip Kumar; Ganguly, Abhijit; Wang, Chen-Hao; Chang, Jan-Kai; Wu, Chih-I; Chen, Li-Chyong; Chen, Kuei-Hsien

2014-11-12

The production of renewable solar fuel through CO2 photoreduction, namely artificial photosynthesis, has gained tremendous attention in recent times due to the limited availability of fossil-fuel resources and global climate change caused by rising anthropogenic CO2 in the atmosphere. In this study, graphene oxide (GO) decorated with copper nanoparticles (Cu-NPs), hereafter referred to as Cu/GO, has been used to enhance photocatalytic CO2 reduction under visible-light. A rapid one-pot microwave process was used to prepare the Cu/GO hybrids with various Cu contents. The attributes of metallic copper nanoparticles (∼4-5 nm in size) in the GO hybrid are shown to significantly enhance the photocatalytic activity of GO, primarily through the suppression of electron-hole pair recombination, further reduction of GO's bandgap, and modification of its work function. X-ray photoemission spectroscopy studies indicate a charge transfer from GO to Cu. A strong interaction is observed between the metal content of the Cu/GO hybrids and the rates of formation and selectivity of the products. A factor of greater than 60 times enhancement in CO2 to fuel catalytic efficiency has been demonstrated using Cu/GO-2 (10 wt % Cu) compared with that using pristine GO.

Tackling CO2 reduction in India through use of CO2 capture and storage (CCS): Prospects and challenges

International Nuclear Information System (INIS)

Shackley, Simon; Verma, Preeti

2008-01-01

CO 2 capture and storage (CCS) is not currently a priority for the Government of India (GOI) because, whilst a signatory to the UNFCCC and Kyoto Protocol, there are no existing greenhouse gas emission reduction targets and most commentators do not envisage compulsory targets for India in the post-2012 phase. The overwhelming priority for the GOI is to sustain a high level of economic growth (8%+) and provision of secure, reliable energy (especially electricity) is one of the widely recognised bottlenecks in maintaining a high growth rate. In such a supply-starved context, it is not easy to envisage adoption of CCS-which increases overall generation capacity and demand for coal without increasing actual electricity supply-as being acceptable. Anything which increases costs-even slightly-is very unlikely to happen, unless it is fully paid for by the international community. The majority viewpoint of the industry and GOI interviewees towards CCS appears to be that it is a frontier technology, which needs to be developed further in the Annex-1 countries to bring down the cost through RD and D and deployment. More RD and D is required to assess in further detail the potential for CO 2 storage in geological reservoirs in India and the international community has an important role to play in cultivating such research

The role of reticular chemistry in the design of CO2 reduction catalysts

Science.gov (United States)

Diercks, Christian S.; Liu, Yuzhong; Cordova, Kyle E.; Yaghi, Omar M.

2018-02-01

The problem with current state-of-the-art catalysts for CO2 photo- or electroreduction is rooted in the notion that no single system can independently control, and thus optimize, the interplay between activity, selectivity and efficiency. At its core, reticular chemistry is recognized for its ability to control, with atomic precision, the chemical and structural features (activity and selectivity) as well as the output optoelectronic properties (efficiency) of porous, crystalline materials. The molecular building blocks that are in a reticular chemist's toolbox are chosen in such a way that the structures are rationally designed, framework chemistry is performed to integrate catalytically active components, and the manner in which these building blocks are connected endows the material with the desired optoelectronic properties. The fact that these aspects can be fine-tuned independently lends credence to the prospect of reticular chemistry contributing to the design of next-generation CO2 reduction catalysts.

Temporal and Spatial Variations in Provincial CO2 Emissions in China from 2005 to 2015 and Assessment of a Reduction Plan

Directory of Open Access Journals (Sweden)

Xuankai Deng

2015-05-01

Full Text Available This study calculated the provincial carbon dioxide (CO2 emissions in China, analyzed the temporal and spatial variations in emissions, and determined the emission intensity from 2005 to 2015. The total emissions control was forecasted in 2015, and the reduction pressure of the 30 provinces in China was assessed based on historical emissions and the 12th five-year (2011–2015 reduction plan. Results indicate that CO2 emissions eventually increased and gradually decreased from east to west, whereas the emission intensity ultimately decreased and gradually increased from south to north. By the end of 2015, the total control of provincial emissions will increase significantly compared to the 2010 level, whereas the emission intensity will decrease. The provinces in the North, East, and South Coast regions will maintain the highest emission levels. The provinces in the Southwest and Northwest regions will experience a rapid growth rate of emissions. However, the national emission reduction target will nearly be achieved if all provinces can implement reduction targets as planned. Pressure indices show that the South Coast and Northwest regions are confronted with a greater reduction pressure of emission intensity. Finally, policy implications are provided for CO2 reductions in China.

A Consideration on Service Business Model for Saving Energy and Reduction of CO2 Emissions Using Inverters

Science.gov (United States)

Kosaka, Michitaka; Yabutani, Takashi

This paper considers the effectiveness of service business approach for reducing CO2 emission. “HDRIVE” is a service business using inverters to reduce energy consumption of motor drive. The business model of this service is changed for finding new opportunities of CO2 emission reduction by combining various factors such as financial service or long-term service contract. Risk analysis of this business model is very important for giving stable services to users for long term. HDRIVE business model is found to be suitable for this objective. This service can be applied to the industries such as chemical or steel industry effectively, where CO2 emission is very large, and has the possibility of creating new business considering CDM or trading CO2 emission right. The effectiveness of this approach is demonstrated through several examples in real business.

Cement replacement by sugar cane bagasse ash: CO2 emissions reduction and potential for carbon credits.

Science.gov (United States)

Fairbairn, Eduardo M R; Americano, Branca B; Cordeiro, Guilherme C; Paula, Thiago P; Toledo Filho, Romildo D; Silvoso, Marcos M

2010-09-01

This paper presents a study of cement replacement by sugar cane bagasse ash (SCBA) in industrial scale aiming to reduce the CO(2) emissions into the atmosphere. SCBA is a by-product of the sugar/ethanol agro-industry abundantly available in some regions of the world and has cementitious properties indicating that it can be used together with cement. Recent comprehensive research developed at the Federal University of Rio de Janeiro/Brazil has demonstrated that SCBA maintains, or even improves, the mechanical and durability properties of cement-based materials such as mortars and concretes. Brazil is the world's largest sugar cane producer and being a developing country can claim carbon credits. A simulation was carried out to estimate the potential of CO(2) emission reductions and the viability to issue certified emission reduction (CER) credits. The simulation was developed within the framework of the methodology established by the United Nations Framework Convention on Climate Change (UNFCCC) for the Clean Development Mechanism (CDM). The State of São Paulo (Brazil) was chosen for this case study because it concentrates about 60% of the national sugar cane and ash production together with an important concentration of cement factories. Since one of the key variables to estimate the CO(2) emissions is the average distance between sugar cane/ethanol factories and the cement plants, a genetic algorithm was developed to solve this optimization problem. The results indicated that SCBA blended cement reduces CO(2) emissions, which qualifies this product for CDM projects. 2010 Elsevier Ltd. All rights reserved.

Potential vehicle fleet CO2 reductions and cost implications for various vehicle technology deployment scenarios in Europe

International Nuclear Information System (INIS)

Pasaoglu, Guzay; Honselaar, Michel; Thiel, Christian

2012-01-01

The continuous rise in demand for road transportation has a significant effect on Europe's oil dependency and emissions of greenhouse gases. Alternative fuels and vehicle technology can mitigate these effects. This study analyses power-train deployment scenarios for passenger cars and light commercial vehicles in EU-27 until 2050. It considers European policy developments on vehicle CO 2 emissions, bio-energy mandates and reductions in the CO 2 footprint of the European energy mix and translates these into comprehensive scenarios for the road transport sector. It quantifies and assesses the potential impact of these scenarios on well-to-wheel (WtW) CO 2 emission reductions primary energy demand evolution, and cost aspects for the prospective vehicle owners. The study reveals that, under the deployed scenarios, the use of bio-fuel blends, technological learning and the deployment of hybrids, battery electric, plug-in hybrid and fuel cell vehicles can decrease WtW CO 2 emissions in EU-27 passenger road transport by 35–57% (compared to 2010 levels) and primary energy demand by 29–51 Mtoe as they would benefit from a future assumed decarbonised electricity and hydrogen mix in Europe. Learning effects can lead to acceptable payback periods for vehicle owners of electric drive vehicles. - Highlights: ► Power-train penetration scenarios for 2010–2050 passenger road transport in Europe. ► A dedicated tool is developed to analyse H 2 production and distribution mix till 2050. ► Alternative vehicles can drastically reduce CO 2 emissions and energy demand. ► Electric vehicles could become cost competitive to conventional vehicles by 2030. ► Policies needed to create adequate momentum and guarantee decarbonised transport.

National energy policies: Obstructing the reduction of global CO2 emissions? An analysis of Swedish energy policies for the district heating sector

International Nuclear Information System (INIS)

Difs, Kristina

2010-01-01

The effect of national energy policies on a local Swedish district heating (DH) system has been studied, regarding the profitability of new investments and the potential for climate change mitigation. The DH system has been optimised regarding three investments: biomass-fuelled CHP (bio CHP), natural gas-fuelled combined cycle CHP (NGCC CHP) and biomass-fuelled heat-only boiler (bio HOB) in two scenarios (with or without national taxes and policy instruments). In both scenarios EU's tradable CO 2 emission permits are included. Results from the study show that when national policies are included, the most cost-effective investment option is the bio CHP technology. However, when national taxes and policy instruments are excluded, the DH system containing the NGCC CHP plant has 30% lower system cost than the bio CHP system. Regardless of the scenario and when coal condensing is considered as marginal electricity production, the NGCC CHP has the largest global CO 2 reduction potential, about 300 ktonne CO 2 . However, the CO 2 reduction potential is highly dependent on the marginal electricity production. Demonstrated here is that national policies such as tradable green certificates can, when applied to DH systems, contribute to investments that will not fully utilise the DH systems' potential for global CO 2 emissions reductions. - Research highlights: →Swedish energy policies are promoting biomass fuelled electricity generating technologies over efficient fossil fuel electricity generating technologies. →An efficient fossil fuel technology like the natural gas combine cycle CHP technology with high power-to-heat ratio has potential to reduce the global CO 2 emissions more than a biomass fuelled electricity generating technology. →Swedish energy policies such as tradable green certificates for renewable electricity can, when applied to district heating systems, contribute to investments that will not fully utilise the district heating systems potential for

Effects of wind intermittency on reduction of CO2 emissions: The case of the Spanish power system

International Nuclear Information System (INIS)

Gutiérrez-Martín, F.; Da Silva-Álvarez, R.A.; Montoro-Pintado, P.

2013-01-01

Renewable energy sources are believed to reduce drastically greenhouse gas emissions that would otherwise be generated from fossil fuels used to generate electricity. This implies that a unit of renewable energy will replace a unit of fossil-fuel, with its CO 2 emissions, on an equivalent basis – with no other effects on the grid. But, the fuel economy and emissions in the existing power systems are not proportional with the electricity production of intermittent sources due to cycling of the fossil-fuel plants that make up the balance of the grid (i.e. changing the power output makes thermal units to operate less efficiently). This study focuses in the interactions between wind generation and thermal plants cycling, by establishing the levels of extra fuel use caused by decreased efficiencies of fossil back-up for wind electricity in Spain. We analyze the production of all thermal plants in 2011, studying scenarios where wind penetration causes major deviations in programming and we define a procedure for quantifying CO 2 reductions using emission factors and efficiency curves from existing installations; the objective is to discuss the real contribution of renewable energy to the environmental targets: the results show that CO 2 reductions are still relevant at high wind penetration, whilst we also suggest alternatives to improve reliability of the power system. - Highlights: ► Comprehensive analysis of interactions of wind and fuel utilities in the power system. ► Fuel economy is not proportional with wind generation due to cycling of fossil plants. ► The results show that CO 2 reductions are still relevant even at high wind penetration. ► Alternatives to improve reliability of future power systems are also pointed out

Active sites of ligand-protected Au25 nanoparticle catalysts for CO2 electroreduction to CO

Science.gov (United States)

Alfonso, Dominic R.; Kauffman, Douglas; Matranga, Christopher

2016-05-01

Recent experimental studies have reported the electrochemical reduction of carbon dioxide (CO2) into CO at atomically precise negatively charged Au25- nanoclusters. The studies showed CO2 conversion at remarkably low overpotentials, but the exact mechanisms and nature of the active sites remain unclear. We used first-principles density functional theory and continuum solvation models to examine the role of the cluster during electrochemical CO2 reduction and analyze the free energies of proposed intermediate species. Contrary to previous assumptions, our results show that the fully ligand protected cluster is not an active CO2 reduction catalyst because formation of the crucial carboxyl intermediate required very high electrochemical potentials. Instead, our calculations suggest that the reduction process likely occurs on a dethiolated gold site, and adsorbed carboxyl intermediate formation was significantly stabilized at dethiolated gold sites. These findings point to the crucial role of exposed metal sites during electrochemical CO2 reduction at gold nanocluster catalysts.

The public perspective of carbon capture and storage for CO{sub 2} emission reductions in China

Energy Technology Data Exchange (ETDEWEB)

Duan, Hongxia [China Center for Energy Economics Research, Building B202, School of Economics, Xiamen University Siming Nanlu No. 422 361005 Xiamen, Fujian (China)

2010-09-15

To explore public awareness of carbon capture and storage (CCS), attitudes towards the use of CCS and the determinants of CCS acceptance in China, a study was conducted in July 2009 based on face-to-face interviews with participants across the country. The result showed that the awareness of CCS was low among the surveyed public in China, compared to other clean energy technologies. Respondents indicated a slightly supportive attitude towards the use of CCS as an alternative technology to CO{sub 2} emission reductions. The regression model revealed that in addition to CCS knowledge, respondents' understanding of the characteristics of CCS, such as the maturity of the technology, risks, capability of CO2 emission reductions, and CCS policy were all significant factors in predicting the acceptance of CCS. The findings suggest that integrating public education and communication into CCS development policy would be an effective strategy to overcome the barrier of low public acceptance. (author)

The public perspective of carbon capture and storage for CO{sub 2} emission reductions in China

Energy Technology Data Exchange (ETDEWEB)

Duan Hongxia, E-mail: hxduan@xmu.edu.c [China Center for Energy Economics Research, Building B202, School of Economics, Xiamen University Siming Nanlu No. 422 361005 Xiamen, Fujian (China)

2010-09-15

To explore public awareness of carbon capture and storage (CCS), attitudes towards the use of CCS and the determinants of CCS acceptance in China, a study was conducted in July 2009 based on face-to-face interviews with participants across the country. The result showed that the awareness of CCS was low among the surveyed public in China, compared to other clean energy technologies. Respondents indicated a slightly supportive attitude towards the use of CCS as an alternative technology to CO{sub 2} emission reductions. The regression model revealed that in addition to CCS knowledge, respondents' understanding of the characteristics of CCS, such as the maturity of the technology, risks, capability of CO2 emission reductions, and CCS policy were all significant factors in predicting the acceptance of CCS. The findings suggest that integrating public education and communication into CCS development policy would be an effective strategy to overcome the barrier of low public acceptance.

Visible light-responded C, N and S co-doped anatase TiO{sub 2} for photocatalytic reduction of Cr(VI)

Energy Technology Data Exchange (ETDEWEB)

Lei, X.F., E-mail: leixuefei69@163.com [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004 (China); Institute of Metallurgical Resource and Environmental Engineering, Northeastern University, Shenyang 110819 (China); Liaoning Key Laboratory of Metallurgical Resource Recycling Science, Shenyang 110819 (China); Liaoning Engineering and Technology Research Center of Boron Resource, Comprehensive, Utilization, Shenyang 110819 (China); Liaoning Provincial Universities Key Laboratory of Boron Resource Ecological, Utilization, Technology and Boron Materials, Shenyang 110819 (China); Xue, X.X.; Yang, H. [Institute of Metallurgical Resource and Environmental Engineering, Northeastern University, Shenyang 110819 (China); Liaoning Key Laboratory of Metallurgical Resource Recycling Science, Shenyang 110819 (China); Liaoning Engineering and Technology Research Center of Boron Resource, Comprehensive, Utilization, Shenyang 110819 (China); Liaoning Provincial Universities Key Laboratory of Boron Resource Ecological, Utilization, Technology and Boron Materials, Shenyang 110819 (China); Chen, C.; Li, X.; Pei, J.X.; Niu, M.C.; Yang, Y.T.; Gao, X.Y. [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004 (China)

2015-10-15

The (C, N and S) co-doped TiO{sub 2} (TH-TiO{sub 2}) samples were synthesized by a sol-gel method calcined at 500 °C, employing butyl titanate as the titanium source and thiourea as the dopant. The structures of TH-TiO{sub 2} samples were characterized by X-ray diffraction (XRD), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS), photoluminescence (PL) spectroscopy, Thermo gravimetry and differential thermal analysis (TG-DTA), Scanning electron microscopy (SEM) and nitrogen adsorption–desorption isotherms. The photocatalytic activities were checked through the photocatalytic reduction of Cr(VI) as a model compound under visible light irradiation. The results showed that the thiourea content played an important role on the microstructure and photocatalytic activity of the samples. According to XPS results, (C, N and S) atoms were successfully co-doped into the nanostructures of TH-TiO{sub 2} samples. TH-TiO{sub 2} samples with thiourea: Ti molar ratio of 1.5 exhibits higher photocatalytic activity than that of the other samples under visible light irradiation, which can be attributed to the synergic effect of the pure anatase structure, the higher light absorption characteristics in visible regions, separation efficiency of electron–hole pairs, the specific surface area and the optimum (C, N and S) content. - Graphical abstract: (C, N and S) co-doped TiO{sub 2} samples show good photocatalytic activity for Cr (VI) reduction under visible light irradiation. - Highlights: • (C, N and S) co-doping in TH-TiO{sub 2} samples can promote the formation of the pure anatase structure. • (C, N and S) atoms were successfully co-doped into the nanostructures of TH-TiO{sub 2} samples. • The band gap energy of TH-TiO{sub 2} samples reduced after (C, N and S) co-doping. • (C, N and S) co-doped TiO{sub 2} samples were effective for the photocatalytic reduction of Cr(VI) under visible light

Evaluation of potential cost reductions from improved amine-based CO2 capture systems

International Nuclear Information System (INIS)

Rao, Anand B.; Rubin, Edward S.; Keith, David W.; Granger Morgan, M.

2006-01-01

Technological innovations in CO 2 capture and storage technologies are being pursued worldwide under a variety of private and government-sponsored R and D programs. While much of this R and D is directed at novel concepts and potential breakthrough technologies, there are also substantial efforts to improve CO 2 capture technologies already in use. In this paper, we focus on amine-based CO 2 capture systems for power plants and other combustion-based applications. The current performance and cost of such systems have been documented in several recent studies. In this paper we examine the potential for future cost reductions that may result from continued process development. We used the formal methods of expert elicitation to understand what experts in this field believe about possible improvements in some of the key underlying parameters that govern the performance and cost of this technology. A dozen leading experts from North America, Europe and Asia participated in this study, providing their probabilistic judgments via a detailed questionnaire coupled with individual interviews. Judgments about detailed technical parameters were then used in an integrated power plant modeling framework (IECM-CS) developed for USDOE to evaluate the performance and costs of alternative carbon capture and sequestration technologies for fossil-fueled power plants. The experts' responses have allowed us to build a picture of how the overall performance and cost of amine-based systems might improve over the next decade or two. Results show how much the cost of CO 2 capture could be reduced via targeted R and D in key areas

International trade and CO{sub 2} emissions; International handel og CO{sub 2}-udledning

Energy Technology Data Exchange (ETDEWEB)

Munksgaard, J.; Pade, L.L. [AKF, Copenhagen (Denmark); Lenzen, M. [Univ. of Sydney (Australia)

2005-04-01

International trade has an impact on national CO{sub 2} emissions and consequently on the ability to fulfil national CO{sub 2} reduction targets. Through goods and services traded in a globally interdependent world, the consumption in each country is linked to greenhouse gas emissions in other countries. It has been argued that in order to achieve equitable reduction targets, international trade has to be taken into account when assessing nations' responsibility for abating climate change. Especially for open economies such as Denmark, greenhouse gases embodied in international traded commodities can have a considerable influence on the national greenhouse gas responsibility. Founded in the concepts of 'producer CO{sub 2} responsibility', 'consumer CO{sub 2} responsibility' and 'CO{sub 2} trade balance' the aim of the present study has been to develop the single-region input-output model as used in a previous study into a multi-region input-output model in order to get a more realistic description of the production technologies actually used in the countries of imports. The study concludes that trade is the key to define CO{sub 2} responsibility on macroeconomics level and that imports should be founded in a multi-region model approach. The study also points at the need to consider the impact from foreign trade when negotiating national reduction targets and base line scenarios within the context of international climate agreements. (BA)

First 2 years of Atmospheric CO2 measurements in the Estany Llong plain (2100 masl, Parc Nacional d'Aigüestortes i Estany de Sant Maurici, Pyrenees, Catalonia, Spain).

Science.gov (United States)

Curcoll, Roger; Recolons, Montserrat; Font, Anna; Agraz, Laura; Parga, Elena; Bacardit, Montse; Camarero, Lluís.; Pueyo, Salva; Rodó, Xavier; Morguí, Josep Anton

2010-05-01

Since April 2009, air samples are being taken bi-weekly at 10 GMT in the plain of the Estany Llong at 2100 masl. Estany Llong air sampling site (ELL, 42°34'29''N 0°57'17''E) is a remote site situated in the SW principal valley of the Parc Nacional d'Aigüestortes i Estany de Sant Maurici. New Flask-sampling equipment for Remote Mountain Sites was developed by the Institut Català de Ciències del Clima (IC3) to allow flask sampling in extreme weather conditions and carrying the sampling equipment for more than 10 km without damaging flasks. Dry Air analysis for CO2 are done at the Laboratory of IC3 using two coupled modified IRGA Licor-7000, where both pressure and flow are externally controlled. Far away from populated areas, ELL site acts as a remote site, but it is also responding to discrete events as snow melting, summer cattle breeding on pastures and trekking frequentation. Series of CO2 obtained are included as part of Long Term Ecological Research (LTER) at the Parc Nacional d'Aigüestortes i Estany de Sant Maurici. In the long term, these measurements show the mountain ecosystems contribution and geomorphologic influence on the CO2 budget of the air masses crossing a mountain range.

Energy Efficiency instead of CO2 levy

International Nuclear Information System (INIS)

Uetz, R.

2005-01-01

This article takes a look at ways of avoiding a future, planned Swiss CO 2 levy by improving the efficiency of energy use. The political situation concerning the reduction of CO 2 emissions in Switzerland is reviewed and the likeliness of the introduction of a CO 2 levy is discussed. Strategies for the reduction of fossil fuel consumption and therefore of CO 2 emissions are looked at, including process optimisation. Recommendations are made on how to approach this work systematically - data collection, assessment of the potential for reduction and the planning of measures to be taken are looked at. The high economic efficiency of immediate action is stressed and typical middle and long-term measures are listed

Synthesis and characterization of Cu{sub 2}Se prepared by hydrothermal co-reduction

Energy Technology Data Exchange (ETDEWEB)

Liu Kegao, E-mail: liukg163@163.co [School of Materials Science and Engineering, Shandong Jianzhu University, Fengming Road, Jinan 250101 (China); Liu Hong, E-mail: hongliu@sdu.edu.c [State Key Laboratory of Crystal Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Wang Jiyang [State Key Laboratory of Crystal Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Shi Lei [School of Materials Science and Engineering, Shandong Jianzhu University, Fengming Road, Jinan 250101 (China)

2009-09-18

Cu{sub 2}Se compounds were synthesized by hydrothermal co-reduction at 150-200 deg. C from CuSO{sub 4}.5H{sub 2}O and SeO{sub 2} in deionized water. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscope (FESEM). Experimental results show that, the product powders with Cu{sub 2}Se phase obtained at 180 and 200 deg. C almost consist of regular hexagonal flakes which grow along (1 1 1) crystal plane. The side lengths between 100 and 200 nm of hexagonal flakes synthesized at 180 deg. C are much smaller than those of the product with 1.3-2 mum side length at 200 deg. C.

Chinese Public’s Willingness to Pay for CO2 Emissions Reductions: A Case Study from Four Provinces/Cities

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Duan Hong-Xia

2014-01-01

Citation: Duan, H.-X., Lü, Y.-L., Li, Y., 2014. Chinese public’s willingness to pay for CO2 emissions reductions: A case study from four provinces/cities. Adv. Clim. Change Res. 5(2, doi: 10.3724/SP.J.1248.2014.100.

Carbon Isotope Composition of Nighttime Leaf-Respired CO2 in the Agricultural-Pastoral Zone of the Songnen Plain, Northeast China

Science.gov (United States)

Cui, Haiying; Wang, Yunbo; Jiang, Qi; Chen, Shiping; Ma, Jian-Ying; Sun, Wei

2015-01-01

Variations in the carbon isotope signature of leaf dark-respired CO2 (δ13CR) within a single night is a widely observed phenomenon. However, it is unclear whether there are plant functional type differences with regard to the amplitude of the nighttime variation in δ13CR. These differences, if present, would be important for interpreting the short-term variations in the stable carbon signature of ecosystem respiration and the partitioning of carbon fluxes. To assess the plant functional type differences relating to the magnitude of the nighttime variation in δ13CR and the respiratory apparent fractionation, we measured the δ13CR, the leaf gas exchange, and the δ13C of the respiratory substrates of 22 species present in the agricultural-pastoral zone of the Songnen Plain, northeast China. The species studied were grouped into C3 and C4 plants, trees, grasses, and herbs. A significant nocturnal shift in δ13CR was detected in 20 of the studied species, with the magnitude of the shift ranging from 1‰ to 5.8‰. The magnitude of the nighttime variation in δ13CR was strongly correlated with the daytime cumulative carbon assimilation, which suggests that variation in δ13CR were influenced, to some extent, by changes in the contribution of malate decarboxylation to total respiratory CO2 flux. There were no differences in the magnitude of the nighttime variation in δ13CR between the C3 and C4 plants, as well as among the woody plants, herbs and graminoids. Leaf respired CO2 was enriched in 13C compared to biomass, soluble carbohydrates and lipids; however the magnitude of enrichment differed between 8 pm and 4 am, which were mainly caused by the changes in δ13CR. We also detected the plant functional type differences in respiratory apparent fractionation relative to biomass at 4 am, which suggests that caution should be exercised when using the δ13C of bulk leaf material as a proxy for the δ13C of leaf-respired CO2. PMID:26356083

Energy-related CO_2 emission in European Union agriculture: Driving forces and possibilities for reduction

International Nuclear Information System (INIS)

Li, Tianxiang; Baležentis, Tomas; Makutėnienė, Daiva; Streimikiene, Dalia; Kriščiukaitienė, Irena

2016-01-01

behind declines in CO_2 emission. According to the SBM, the lowest carbon shadow prices are observed in France, Finland, Sweden, Denmark, the Netherlands, Poland, and Belgium. These countries thus have the highest potential for reduction in CO_2 emission. The results imply that measures to increase energy efficiency are a more effective means to reduce CO_2 emissions than are changes in the fuel-mix.

Co-benefit analysis of an air quality management plan and greenhouse gas reduction strategies in the Seoul metropolitan area

International Nuclear Information System (INIS)

Chae, Yeora

2010-01-01

This study assesses the co-benefits of an air quality management plan and CO 2 emission control measures in the Seoul metropolitan area. This co-benefit analysis includes NO x , PM 10 and CO 2 emission reductions and cost estimations, yielding cost-effectiveness values for each of the measures. It has been found that fuel switching from BC-oil to LNG, CNG bus operation are most cost effective in NO x and PM 10 emission reduction. For CO 2 emission reduction, landfill gas reuse and fuel switching were the most effective option. The correlation of cost-effectiveness analysis indicated that fuel switching and CNG bus operation were the most cost effective option to reduce NO x and CO 2 , PM 10 and CO 2 emissions at the same time. Based on cost effectiveness and co-benefit analysis, this study developed an alternative scenario of emission reduction measures through optimization in order to achieve both air quality improvements and CO 2 reduction targets at the minimum cost. These integrated environmental strategies make it possible to reduce 10.3 Mt of CO 2 emissions, which is beyond the target of the CO 2 reduction strategy, and achieve air quality improvement targets together and at a lower cost than the CO 2 emission reduction and air quality improvement measures combined.

Amorphizing of Cu Nanoparticles toward Highly Efficient and Robust Electrocatalyst for CO2 Reduction to Liquid Fuels with High Faradaic Efficiencies.

Science.gov (United States)

Duan, Yan-Xin; Meng, Fan-Lu; Liu, Kai-Hua; Yi, Sha-Sha; Li, Si-Jia; Yan, Jun-Min; Jiang, Qing

2018-04-01

Conversion of carbon dioxide (CO 2 ) into valuable chemicals, especially liquid fuels, through electrochemical reduction driven by sustainable energy sources, is a promising way to get rid of dependence on fossil fuels, wherein developing of highly efficient catalyst is still of paramount importance. In this study, as a proof-of-concept experiment, first a facile while very effective protocol is proposed to synthesize amorphous Cu NPs. Unexpectedly, superior electrochemical performances, including high catalytic activity and selectivity of CO 2 reduction to liquid fuels are achieved, that is, a total Faradaic efficiency of liquid fuels can sum up to the maximum value of 59% at -1.4 V, with formic acid (HCOOH) and ethanol (C 2 H 6 O) account for 37% and 22%, respectively, as well as a desirable long-term stability even up to 12 h. More importantly, this work opens a new avenue for improved electroreduction of CO 2 based on amorphous metal catalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pursuing air pollutant co-benefits of CO2 mitigation in China: A provincial leveled analysis

International Nuclear Information System (INIS)

Dong, Huijuan; Dai, Hancheng; Dong, Liang; Fujita, Tsuyoshi; Geng, Yong; Klimont, Zbigniew; Inoue, Tsuyoshi; Bunya, Shintaro; Fujii, Minoru; Masui, Toshihiko

2015-01-01