In the carbonate industry,deep decarbonization strategies are necessary to effectively remediate CO_(2).These strategies mainly include both sustainable energy supplies and the conversion of CO_(2)in downstream proces...In the carbonate industry,deep decarbonization strategies are necessary to effectively remediate CO_(2).These strategies mainly include both sustainable energy supplies and the conversion of CO_(2)in downstream processes.This study developed a coupled process of biomass chemical looping H2 production and reductive calcination of CaCO_(3).Firstly,a mass and energy balance of the coupled process was established in Aspen Plus.Following this,process optimization and energy integration were implemented to provide optimized operation conditions.Lastly,a life cycle assessment was carried out to assess the carbon footprint of the coupled process.Results reveal that the decomposition temperature of CaCO_(3)in an H_(2)atmosphere can be reduced to 780℃(generally around 900℃),and the conversion of CO_(2)from CaCO_(3)decomposition reached 81.33%with an H2:CO ratio of 2.49 in gaseous products.By optimizing systemic energy through heat integration,an energy efficiency of 86.30%was achieved.Additionally,the carbon footprint analysis revealed that the process with energy integration had a low global warming potential(GWP)of-2.624 kg·kg^(-1)(CO_(2)/CaO).Conclusively,this work performed a systematic analysis of introducing biomass-derived H_(2)into CaCO_(3)calcination and demonstrated the positive role of reductive calcination using green H_(2)in mitigating CO_(2)emissions within the carbonate industry.展开更多
This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hyd...This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hydrogen atmosphere at 1100°C,we tried to find out the minute changes.In this experiment,a refractory brick was prepared by andalusite,mullite chamotte,and clay as raw materials and heated to 1100°C in a 100%hydrogen atmosphere for 72 h.It was found that the strength of the brick was decreased and the color was changed to black by the reduction of impurities.And in addition,this study covered research on the slaking risk of MgO raw materials because the minimum temperature is expected to 400°C in fluidized reduction furnaces unlike shaft furnaces.展开更多
The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous me...The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO_(2)(CO_(2)RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mechanisms for CO_(2)RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low stability.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO_(2) reduction.展开更多
Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon neutrality.HCOOH is one of the most promising products obtained by electrochemical reduction of CO_(...Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon neutrality.HCOOH is one of the most promising products obtained by electrochemical reduction of CO_(2) due to its high energy value as estimated by market price per energy unit and wide application in chemical industry.Biomass is the most abundant renewable resource in the natural world.Coupling biomass oxidative conversion with CO_(2)RR driven by renewable electricity would well achieve carbon negativity.In this work,we comprehensively reviewed the current research progress on CO_(2)RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added products.Sn-and Bi-based electrocatalysts are discussed for CO_(2)RR with regards to the structure of the catalyst and reaction mechanisms.Electro-oxidation reactions of biomass derived sugars,alcohols,furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction(OER)in the conventional electrolysis process.It was recommended that to further improve the efficiency of the coupled system,future work should be focused on the development of more efficient and stable catalysts,careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.展开更多
It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) wi...It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) with layered structure was explored as the 2e^(-) ORR electrocatalyst,which not only showed the highest 2e^(-) selectivity more than 97%,but also delivered a slight activity decay after 5000 cycles in alkaline media.Moreover,when NiTe_(2) was assembled as the electrocatalyst in H-type electrolyzer,the on-site yield of H_(2)O_(2) could reach up to 672 mmol h^(-1)g^(-1) under 0.45 V vs.RHE.Further in situ Raman spectra,theoretical calculation and post microstructural analysis synergistically unveiled that such a good 2e^(-) ORR performance could be credited to the intrinsic layered crystal structure,the high compositional stability,as well as the electron modulation on the active site Ni atoms by neighboring Te atoms,leading to the exposure of active sites as well as the optimized adsorption free energy of Ni to –OOH.More inspiringly,such telluride electrocatalyst has also been demonstrated to exhibit high activity and selectivity towards 2e^(-) ORR in neutral media.展开更多
This study explores how the chemical interaction between magnesium hydride(MgH_(2))and the additive CrO_(3) influences the hydrogen/lithium storage characteristics of MgH_(2).We have observed that a 5 wt.%CrO_(3) addi...This study explores how the chemical interaction between magnesium hydride(MgH_(2))and the additive CrO_(3) influences the hydrogen/lithium storage characteristics of MgH_(2).We have observed that a 5 wt.%CrO_(3) additive reduces the dehydrogenation activation energy of MgH_(2) by 68 kJ/mol and lowers the required dehydrogenation temperature by 80℃.CrO_(3) added MgH_(2) was also tested as an anode in an Li ion battery,and it is possible to deliver over 90%of the total theoretical capacity(2038 mAh/g).Evidence for improved reversibility in the battery reaction is found only after the incorporation of additives with MgH_(2).In depth characterization study by X-ray diffraction(XRD)technique provides convincing evidence that the CrO_(3) additive interacts with MgH_(2) and produces Cr/MgO byproducts.Gibbs free energy analyses confirm the thermodynamic feasibility of conversion from MgH_(2)/CrO_(3) to MgO/Cr,which is well supported by the identification of Cr(0)in the powder by X ray photoelectron spectroscopy(XPS)technique.Through high resolution transmission electron microscopy(HRTEM)and energy dispersive spectroscopy(EDS)we found evidence for the presence of 5 nm size Cr nanocrystals on the surface of MgO rock salt nanoparticles.There is also convincing ground to consider that MgO rock salt accommodates Cr in the lattice.These observations support the argument that creation of active metal–metal dissolved rock salt oxide interface may be vital for improving the reactivity of MgH_(2),both for the improved storage of hydrogen and lithium.展开更多
Electrochemical nitrate reduction to ammonia(NRA) can realize the green synthesis of ammonia(NH3) at ambient conditions, and also remove nitrate contamination in water. However, the current catalysts for NRA still fac...Electrochemical nitrate reduction to ammonia(NRA) can realize the green synthesis of ammonia(NH3) at ambient conditions, and also remove nitrate contamination in water. However, the current catalysts for NRA still face relatively low NH3yield rate and poor stability. We present here a core-shell heterostructure comprising cobalt oxide anchored on copper oxide nanowire arrays(CuO NWAs@Co_(3)O_(4)) for efficient NRA. The CuO NWAs@Co_(3)O_(4)demonstrates significantly enhanced NRA performance in alkaline media in comparison with plain CuO NWAs and Co_(3)O_(4)flocs. Especially, at-0.23 V vs. RHE, NH_(3) yield rate of the CuO NWAs@Co_(3)O_(4)reaches 1.915 mmol h^(-1)cm^(-2),much higher than those of CuO NWAs(1.472 mmol h^(-1)cm^(-2)), Co_(3)O_(4)flocs(1.222 mmol h^(-1)cm^(-2)) and recent reported Cu-based catalysts.It is proposed that the synergetic effects of the heterostructure combing atom hydrogen adsorption and nitrate reduction lead to the enhanced NRA performance.展开更多
The electrochemical CO_(2)reduction reaction to produce multi-carbon(C_(2+)) hydrocarbons or oxygenate compounds is a promising route to obtain a renewable fuel of high energy density.However,producing C_(2+)at high c...The electrochemical CO_(2)reduction reaction to produce multi-carbon(C_(2+)) hydrocarbons or oxygenate compounds is a promising route to obtain a renewable fuel of high energy density.However,producing C_(2+)at high current densities is still a challenge.Herein,we develop a Cu-Zn alloy/Cu-Zn aluminate oxide composite electrocatalytic system for enhanced conversion of CO_(2)to C_(2+)products.The Cu-Zn-Al-Layered Double Hydroxide(LDH) is used as a precursor to decompose into uniform Cu-Zn oxide/Cu-Zn aluminate pre-catalyst.Under electrochemical reduction,Cu-Zn oxide generates Cu-Zn alloy while Cu-Zn aluminate oxide remains unchanged.The alloy and oxide are closely stacked and arranged alternately,and the aluminate oxide induces the strong electron interaction of Cu,Zn and Al,creating a large number of highly active reaction interfaces composed of 0 to+3 valence metal sites.With the help of the interface effect,the optimized Cu_(9)Zn_(1)/Cu_(0.8)Zn_(0.2)Al_(2)O_(4)catalyst achieves a Faradaic efficiency of 88.5% for C_(2+)products at a current density of 400 mA cm^(-2)at-1.15 V versus reversible hydrogen electrode.The in-situ Raman and attenuate total reflectance-infrared absorption spectroscopy(ATR-IRAS) spectra show that the aluminate oxide at the interface significantly enhances the adsorption and activation of CO_(2)and the dissociation of H2O and strengthens the adsorption of CO intermediates,and the alloy promotes the C-C coupling to produce C_(2+)products.This work provides an efficient strategy to construct highly active reaction interfaces for industrial-scale electrochemical CO_(2)RR.展开更多
The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are u...The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.展开更多
The growth of electrochemically inert segregation layers on the surface of solid oxide fuel cell cathodes has become a bottleneck restricting the development of perovskite-structured oxygen reduction catalysts.Here,we...The growth of electrochemically inert segregation layers on the surface of solid oxide fuel cell cathodes has become a bottleneck restricting the development of perovskite-structured oxygen reduction catalysts.Here,we report a new discovery in which enriched Ba and Fe ions on the near-surface of Nd_(1/2)Ba_(1/2)Co_(1/3)Fe_(1/3)Mn_(1/3)O_(3-δ)spontaneously agglomerate into dispersed Ba_(5)Fe_(2)O_(8) nanoparticles and maintain a highly active and durable perovskite structure on the surface.This unique surface selfcleaning phenomenon is related to the low average potential energy of Ba_(5)Fe_(2)O_(8),which is grown on the near-surface layer.The electrochemically inert Ba_(5)Fe_(2)O_(8) segregation layer on the near-surface of the perovskite catalyst achieves self-cleaning by regulating the formation energy of enriched metal oxides.This self-cleaned perovskite surface exhibits an ultrafast oxygen exchange rate,high catalytic activity for the oxygen reduction reaction,and good adaptability to the actual working conditions of solid oxide fuel cell stacks.This study paves a new way for overcoming the stubborn problem of perovskite catalyst surface deactivation and enriches the scientific knowledge of surface catalysis.展开更多
Metal-air batteries face a great challenge in developing efficient and durable low-cost oxygen reduction reaction(ORR)electrocatalysts.Single-atom iron catalysts embedded into nitrogen doped carbon(Fe-N-C)have emerged...Metal-air batteries face a great challenge in developing efficient and durable low-cost oxygen reduction reaction(ORR)electrocatalysts.Single-atom iron catalysts embedded into nitrogen doped carbon(Fe-N-C)have emerged as attractive materials for potential replacement of Pt in ORR,but their catalytic performance was limited by the symmetrical electronic structure distribution around the single-atom Fe site.Here,we report our findings in significantly enhancing the ORR performance of Fe-N-C by moderate Fe_(2)O_(3) integration via the strong electronic interaction.Remarkably,the optimized catalyst(M-Fe_(2)O_(3)/Fe_(SA)@NC)exhibits excellent activity,durability and good tolerance to methanol,outperforming the benchmark Pt/C catalyst.When M-Fe_(2)O_(3)/Fe_(SA)@NC catalyst was used in a practical zinc-air battery assembly,peak power density of 155 mW cm^(-2)and specific capacity of 762 mA h g_(Zn)^(-1)were achieved and the battery assembly has shown superior cycling stability over a period of 200 h.More importantly,theoretical studies suggest that the introduction of Fe_(2)O_(3) can evoke the crystal field alteration and electron redistribution on single Fe atoms,which can break the symmetric charge distribution of Fe-N_(4) and thereby optimize the corresponding adsorption energy of intermediates to promote the O_(2)reduction.This study provides a new pathway to promote the catalytic performance of single-atom catalysts.展开更多
Mixed metal oxide(MMO) represents a critical class of materials that can allow for obtaining a dynamic interface between its components:reduced metal and its metal oxide counterpart during an electrocatalytic reaction...Mixed metal oxide(MMO) represents a critical class of materials that can allow for obtaining a dynamic interface between its components:reduced metal and its metal oxide counterpart during an electrocatalytic reaction.Here,a synthetic method utilizing a MOF-derived micro/mesoporous carbon as a template to prepare sub-2 nm MMO catalysts for CO_(2) electro reduction is reported.Starting from the zeolite imidazolate framework(ZIF-8),the pyrolyzed derivatives were used to synthesize sub-2 nm Pd-Ni MMO with different compositions.The Ni-rich(Pd_(20)-Ni_(80)/ZC) catalyst exhibits unexpectedly superior performance for CO production with an improved Faradaic efficiency(FE) of 95.3% at the current density of 200 mA cm^(-2) at-0.56 V vs.reversible hydrogen electrode(RHE) compared to other Pd-Ni compositions.X-ray photoelectron spectroscopy(XPS) analysis confirms the presence of Ni^(2+) and Pd^(2+) in all compositions,demonstrating the presence of MMO.Density functional theory(DFT) calculation reveals that the lower CO binding energy on the surface of the Pd_(20)-Ni_(80) cluster eases CO desorption,thus increasing its production.This work provides a general synthetic strategy for MMO electrocatalysts and can pave a new way for screening multimetallic catalysts with a dynamic electrochemical interface.展开更多
Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic perf...Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic performance and electrochemical behavior of complex metal oxides,especially perovskite oxides,is rarely reported.Here,the inorganic perovskite oxide Ag-doped(La_(0.8)Sr_(0.2))_(0.95)Ag_(0.05)MnO_(3-δ)(LSA0.05M)is reported as an efficient electrocatalyst for ECR to CO for the first time,which exhibits a Faradaic efficiency(FE)of 84.3%,a remarkable mass activity of 75Ag^(-1)(normalized to the mass of Ag),and stability of 130 h at a moderate overpotential of 0.79 V.The LSA0.05M catalyst experiences structure reconstruction during ECR,creating the in operando-formed interface between the perovskite and the evolved Ag phase.The evolved Ag is uniformly distributed with a small particle size on the perovskite surface.Theoretical calculations indicate the reconstruction of LSA0.05M during ECR and reveal that the perovskite-Ag interface provides adsorption sites for CO_(2) and accelerates the desorption of the*CO intermediate to enhance ECR.This study presents a novel high-performance perovskite catalyst for ECR andmay inspire the future design of electrocatalysts via the in operando formation of metal-metal oxide interfaces.展开更多
Crystal growth of tungsten during hydrogen reduction of tungsten oxide (WO3) to prepare coarse grain tungsten powder at high temperature (950 ℃) was studied. The phase composition and morphologies of products were in...Crystal growth of tungsten during hydrogen reduction of tungsten oxide (WO3) to prepare coarse grain tungsten powder at high temperature (950 ℃) was studied. The phase composition and morphologies of products were investigated by means of XRD and SEM. The results show that the reduction sequence of hydrogen reduction of WO3 is WO3→WO2.9→W18O49→WO2→W. The step of WO2→W is the critical step which determines the grain size of tungsten powder. The partial pressure (pH2O/pH2) of H2O within powder layer shows strong effect on the nucleation and grain growth of tungsten. By increasing the pH2O/pH2 within powder layer, well-developed coarse grain tungsten powder with particle size above 15 μm is obtained. After carburizing, the powder can be used to produce ultra-coarse grain cemented carbide with grain size above 5 μm.展开更多
Electrocatalytic oxygen reduction reaction (ORR) via two-electron pathway is a promising approach to decentralized and on-site hydrogen peroxide (H_(2)O_(2)) production beyond the traditional anthraquinone process.In ...Electrocatalytic oxygen reduction reaction (ORR) via two-electron pathway is a promising approach to decentralized and on-site hydrogen peroxide (H_(2)O_(2)) production beyond the traditional anthraquinone process.In recent years,electrochemical H_(2)O_(2) production in acidic media has attracted increasing attention owing to its stronger oxidizing capacity,superior stability,and higher compatibility with various applications.Here,recent advances of H_(2)O_(2) electrosynthesis in acidic media are summarized.Specifically,fundamental aspects of two-electron ORR mechanism are firstly presented with an emphasis on the pH effect on catalytic performance.Major categories of promising electrocatalysts are then reviewed,including noble-metal-based materials,non-noble-metal single-atom catalysts,non-noblemetal compounds,and metal-free carbon-based materials.The innovative development of electrochemical devices and in situ/on-site application of electrogenerated H_(2)O_(2) are also highlighted to bridge the gap between laboratory-scale fundamental research and practically relevant H_(2)O_(2) electrosynthesis.Finally,critical perspectives on present challenges and promising opportunities for future research are provided.展开更多
Steel production causes a third of all industrial CO_(2) emissions due to the use of carbon-based substances as reductants for iron ores,making it a key driver of global warming.Therefore,research efforts aim to repla...Steel production causes a third of all industrial CO_(2) emissions due to the use of carbon-based substances as reductants for iron ores,making it a key driver of global warming.Therefore,research efforts aim to replace these reductants with sustainably produced hydrogen.Hydrogen-based direct reduction(HyDR)is an attractive processing technology,given that direct reduction(DR)furnaces are routinely operated in the steel industry but with CH_(4) or CO as reductants.Hydrogen diffuses considerably faster through shaft-furnace pellet agglomerates than carbon-based reductants.However,the net reduction kinetics in HyDR remains extremely sluggish for high-quantity steel production,and the hydrogen consumption exceeds the stoichiometrically required amount substantially.Thus,the present study focused on the improved understanding of the influence of spatial gradients,morphology,and internal microstructures of ore pellets on reduction efficiency and metallization during HyDR.For this purpose,commercial DR pellets were investigated using synchrotron high-energy X-ray diffraction and electron microscopy in conjunction with electron backscatter diffraction and chemical probing.Revealing the interplay of different phases with internal interfaces,free surfaces,and associated nucleation and growth mechanisms provides a basis for developing tailored ore pellets that are highly suited for a fast and efficient HyDR.展开更多
The hydrogen reduction of tungsten oxides WO_(2.90),W_(20)O_(58) and WO_3 were directly studied using high temperature X-ray diffraction analysis.The differences between tetragonal WO_(2.90) and monoclinic W_(20)O_(58...The hydrogen reduction of tungsten oxides WO_(2.90),W_(20)O_(58) and WO_3 were directly studied using high temperature X-ray diffraction analysis.The differences between tetragonal WO_(2.90) and monoclinic W_(20)O_(58) were discussed.Pure β-W was obtained from oxide WO_(2.90),while there appears small amount of WO_2 during the reduction of W_(20)O_(58) to β-W.展开更多
The Earth’s sustainable development is threatened by the increasing atmospheric COlevel which can be attributed to the imbalance of COdue to the rapid consumption of fossil fuels caused by human activities and the sl...The Earth’s sustainable development is threatened by the increasing atmospheric COlevel which can be attributed to the imbalance of COdue to the rapid consumption of fossil fuels caused by human activities and the slow absorption and conversion of COby nature. One of the efficient methods for reconstructing the balance of COshould involve the rapid conversion of COinto fuels and chemicals.The hydrogenation of COwith gaseous hydrogen is currently considered to be the most commercially feasible synthetic route, however, the supply of safe and economical hydrogen sources poses a significant challenge to up-scaling application. Direct utilization of hydrogen from dissociation of water, the most abundant, cheap and clean hydrogen resource, for the reduction of COwould be one of the most promising approaches for COutilization. This paper provides an overview of the current advances in research on highly efficient reduction of COor NaHCO, a representative compound of CO, into formic acid/formate by in situ hydrogen from water dissociation with a metal/metal oxide redox cycle under mild hydrothermal conditions.展开更多
The ultra-fine chromic oxide powder was prepared by a novel gas-solid reduction reaction.Na2CrO4 was firstly reduced with hydrogen at 400-600 ℃.The obtained reduction products,mainly the mixture of NaCrO2 and sodium ...The ultra-fine chromic oxide powder was prepared by a novel gas-solid reduction reaction.Na2CrO4 was firstly reduced with hydrogen at 400-600 ℃.The obtained reduction products,mainly the mixture of NaCrO2 and sodium hydroxide(NaOH),were converted into chromic oxide through hydrolysis followed by calcination.The obtained chromic oxide product was characterized by powder X-ray diffraction(XRD) and SEM.The results show that the hydrolysis process of sodium chromite is the key step and lower reduction temperature helps intensify the hydrolysis process.展开更多
The hydrogen reduction of tungsten oxides WO_(272)and WO_2 were studied directly using high-temperature X-ray diffraction analysis,The pure β-W was obtained from the reduction of WO_(272)The transformation of β-W to...The hydrogen reduction of tungsten oxides WO_(272)and WO_2 were studied directly using high-temperature X-ray diffraction analysis,The pure β-W was obtained from the reduction of WO_(272)The transformation of β-W to x-W was also studied in both hydrogen and nitrogen.The forming condition of β-W from WO_2 was discussed.Finally.a complete schematic diagram of reduction of tungsten oxides was given in this paper.展开更多
基金support from the National Natural Science Foundation of China(21978128,91934302)partial support from the State Key Laboratory of Materials-oriented Chemical Engineering(ZK202006)also acknowledged.Additionallysupported by the“Cultivation Program for The Excellent Doctoral Dissertation of Nanjing Tech University(3800124701)”.
文摘In the carbonate industry,deep decarbonization strategies are necessary to effectively remediate CO_(2).These strategies mainly include both sustainable energy supplies and the conversion of CO_(2)in downstream processes.This study developed a coupled process of biomass chemical looping H2 production and reductive calcination of CaCO_(3).Firstly,a mass and energy balance of the coupled process was established in Aspen Plus.Following this,process optimization and energy integration were implemented to provide optimized operation conditions.Lastly,a life cycle assessment was carried out to assess the carbon footprint of the coupled process.Results reveal that the decomposition temperature of CaCO_(3)in an H_(2)atmosphere can be reduced to 780℃(generally around 900℃),and the conversion of CO_(2)from CaCO_(3)decomposition reached 81.33%with an H2:CO ratio of 2.49 in gaseous products.By optimizing systemic energy through heat integration,an energy efficiency of 86.30%was achieved.Additionally,the carbon footprint analysis revealed that the process with energy integration had a low global warming potential(GWP)of-2.624 kg·kg^(-1)(CO_(2)/CaO).Conclusively,this work performed a systematic analysis of introducing biomass-derived H_(2)into CaCO_(3)calcination and demonstrated the positive role of reductive calcination using green H_(2)in mitigating CO_(2)emissions within the carbonate industry.
基金supported by the Korea Planning & Evaluation Institute of Industrial Technology (KEIT)the Ministry of Trade, Industry & Energy (MOTIE, Korea) of the Republic of Korea (No. RS2023-00262421)
文摘This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hydrogen atmosphere at 1100°C,we tried to find out the minute changes.In this experiment,a refractory brick was prepared by andalusite,mullite chamotte,and clay as raw materials and heated to 1100°C in a 100%hydrogen atmosphere for 72 h.It was found that the strength of the brick was decreased and the color was changed to black by the reduction of impurities.And in addition,this study covered research on the slaking risk of MgO raw materials because the minimum temperature is expected to 400°C in fluidized reduction furnaces unlike shaft furnaces.
基金funded by the National Natural Science Foundation of China,China (Nos.52272303 and 52073212)the General Program of Municipal Natural Science Foundation of Tianjin,China (Nos.17JCYBJC22700 and 17JCYBJC17000)the State Scholarship Fund of China Scholarship Council,China (Nos.201709345012 and 201706255009)。
文摘The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO_(2)(CO_(2)RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mechanisms for CO_(2)RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low stability.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO_(2) reduction.
基金supported by the National Key R&D Program of China(2022YFA2105900)the National Natural Science Foundation of China(No.22178197)。
文摘Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon neutrality.HCOOH is one of the most promising products obtained by electrochemical reduction of CO_(2) due to its high energy value as estimated by market price per energy unit and wide application in chemical industry.Biomass is the most abundant renewable resource in the natural world.Coupling biomass oxidative conversion with CO_(2)RR driven by renewable electricity would well achieve carbon negativity.In this work,we comprehensively reviewed the current research progress on CO_(2)RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added products.Sn-and Bi-based electrocatalysts are discussed for CO_(2)RR with regards to the structure of the catalyst and reaction mechanisms.Electro-oxidation reactions of biomass derived sugars,alcohols,furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction(OER)in the conventional electrolysis process.It was recommended that to further improve the efficiency of the coupled system,future work should be focused on the development of more efficient and stable catalysts,careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.
基金supported by the National MCF Energy R&D Program of China (2018YFE0306105)the National Key R&D Program of China (2020YFA0406104, 2020YFA0406101)+8 种基金the Innovative Research Group Project of the National Natural Science Foundation of China (51821002)the National Natural Science Foundation of China (52201269, 52302296, 51972216)the Natural Science Foundation of Jiangsu Province (BK20220028, BK20210735)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province (21KJB430043)the Collaborative Innovation Center of Suzhou Nano Science & Technology, the 111 Projectthe Suzhou Key Laboratory of Functional Nano & Soft Materials, the Jiangsu Key Laboratory for Advanced Negative Carbon Technologiesthe Science and Technology Development Fund, Macao SAR (0009/2022/ITP)the funding from Gusu leading talent plan for scientific and technological innovation and entrepreneurship (ZXL2022487)China Scholarship Council (CSC) for the Ph.D. fellowship。
文摘It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) with layered structure was explored as the 2e^(-) ORR electrocatalyst,which not only showed the highest 2e^(-) selectivity more than 97%,but also delivered a slight activity decay after 5000 cycles in alkaline media.Moreover,when NiTe_(2) was assembled as the electrocatalyst in H-type electrolyzer,the on-site yield of H_(2)O_(2) could reach up to 672 mmol h^(-1)g^(-1) under 0.45 V vs.RHE.Further in situ Raman spectra,theoretical calculation and post microstructural analysis synergistically unveiled that such a good 2e^(-) ORR performance could be credited to the intrinsic layered crystal structure,the high compositional stability,as well as the electron modulation on the active site Ni atoms by neighboring Te atoms,leading to the exposure of active sites as well as the optimized adsorption free energy of Ni to –OOH.More inspiringly,such telluride electrocatalyst has also been demonstrated to exhibit high activity and selectivity towards 2e^(-) ORR in neutral media.
基金supported by the projects UIDB/00481/2020 and UIDP/00481/2020-Fundação para a Ciência e a Tecnologia,DOI 10.54499/UIDB/00481/2020(https://doi.org/10.54499/UIDB/00481/2020)and DOI 10.54499/UIDP/00481/2020(https://doi.org/10.54499/UIDP/00481/2020)supported by CENTRO-01-0145-FEDER-022083-Centro Portugal Regional Operational Programme(Centro 2020),under the PORTUGAL 2020 Partnership Agreement,through the European Regional Development Fund(ERDF).This article is a result of the Innovation Pact“NGS-New Generation Storage”(C644936001-00000045)+3 种基金by“NGS”Consortium,co-financed by NextGeneration EU,through the Incentive System“Agendas para a Inovação Empresarial”(“Agendas for Business Innovation”)within the Recovery and Resilience Plan(PRR).D.P acknowledges FCT,Portugal for the financial support with reference CEECIND/04158/2017(https://doi.org/10.54499/CEECIND/04158/2017/CP1459/CT0029)funding from the SMART-ER project,funded by the European Union’s Horizon 2020 research and innovation programme under Grant Agreement#101016888.support granted by the Recovery and Resilience Plan(PRR)and by the Next Generation EU European Funds to Universidade de Aveiro,through the Agenda for Business Innovation“NGS-Next Generation Storage”(Project no 02/C05-i01.01/2022 with the application C644936001-00000045).
文摘This study explores how the chemical interaction between magnesium hydride(MgH_(2))and the additive CrO_(3) influences the hydrogen/lithium storage characteristics of MgH_(2).We have observed that a 5 wt.%CrO_(3) additive reduces the dehydrogenation activation energy of MgH_(2) by 68 kJ/mol and lowers the required dehydrogenation temperature by 80℃.CrO_(3) added MgH_(2) was also tested as an anode in an Li ion battery,and it is possible to deliver over 90%of the total theoretical capacity(2038 mAh/g).Evidence for improved reversibility in the battery reaction is found only after the incorporation of additives with MgH_(2).In depth characterization study by X-ray diffraction(XRD)technique provides convincing evidence that the CrO_(3) additive interacts with MgH_(2) and produces Cr/MgO byproducts.Gibbs free energy analyses confirm the thermodynamic feasibility of conversion from MgH_(2)/CrO_(3) to MgO/Cr,which is well supported by the identification of Cr(0)in the powder by X ray photoelectron spectroscopy(XPS)technique.Through high resolution transmission electron microscopy(HRTEM)and energy dispersive spectroscopy(EDS)we found evidence for the presence of 5 nm size Cr nanocrystals on the surface of MgO rock salt nanoparticles.There is also convincing ground to consider that MgO rock salt accommodates Cr in the lattice.These observations support the argument that creation of active metal–metal dissolved rock salt oxide interface may be vital for improving the reactivity of MgH_(2),both for the improved storage of hydrogen and lithium.
基金the financial support from National Natural Science Foundation of China (No. 21972102)National Key Research and Development Program of China (2021YFA0910400)+3 种基金Natural Science Foundation of Jiangsu Province (BK20200991)Suzhou Science and Technology Planning Project (SS202016)the USTS starting fund (No.332012104)the Natural Science Foundation of Suzhou University of Science and Technology (No.342134401)。
文摘Electrochemical nitrate reduction to ammonia(NRA) can realize the green synthesis of ammonia(NH3) at ambient conditions, and also remove nitrate contamination in water. However, the current catalysts for NRA still face relatively low NH3yield rate and poor stability. We present here a core-shell heterostructure comprising cobalt oxide anchored on copper oxide nanowire arrays(CuO NWAs@Co_(3)O_(4)) for efficient NRA. The CuO NWAs@Co_(3)O_(4)demonstrates significantly enhanced NRA performance in alkaline media in comparison with plain CuO NWAs and Co_(3)O_(4)flocs. Especially, at-0.23 V vs. RHE, NH_(3) yield rate of the CuO NWAs@Co_(3)O_(4)reaches 1.915 mmol h^(-1)cm^(-2),much higher than those of CuO NWAs(1.472 mmol h^(-1)cm^(-2)), Co_(3)O_(4)flocs(1.222 mmol h^(-1)cm^(-2)) and recent reported Cu-based catalysts.It is proposed that the synergetic effects of the heterostructure combing atom hydrogen adsorption and nitrate reduction lead to the enhanced NRA performance.
基金supported by the National Natural Science Foundation of China (NSFC)(22075201)the National Key Research and Development Program of China (2022YFB4101800)。
文摘The electrochemical CO_(2)reduction reaction to produce multi-carbon(C_(2+)) hydrocarbons or oxygenate compounds is a promising route to obtain a renewable fuel of high energy density.However,producing C_(2+)at high current densities is still a challenge.Herein,we develop a Cu-Zn alloy/Cu-Zn aluminate oxide composite electrocatalytic system for enhanced conversion of CO_(2)to C_(2+)products.The Cu-Zn-Al-Layered Double Hydroxide(LDH) is used as a precursor to decompose into uniform Cu-Zn oxide/Cu-Zn aluminate pre-catalyst.Under electrochemical reduction,Cu-Zn oxide generates Cu-Zn alloy while Cu-Zn aluminate oxide remains unchanged.The alloy and oxide are closely stacked and arranged alternately,and the aluminate oxide induces the strong electron interaction of Cu,Zn and Al,creating a large number of highly active reaction interfaces composed of 0 to+3 valence metal sites.With the help of the interface effect,the optimized Cu_(9)Zn_(1)/Cu_(0.8)Zn_(0.2)Al_(2)O_(4)catalyst achieves a Faradaic efficiency of 88.5% for C_(2+)products at a current density of 400 mA cm^(-2)at-1.15 V versus reversible hydrogen electrode.The in-situ Raman and attenuate total reflectance-infrared absorption spectroscopy(ATR-IRAS) spectra show that the aluminate oxide at the interface significantly enhances the adsorption and activation of CO_(2)and the dissociation of H2O and strengthens the adsorption of CO intermediates,and the alloy promotes the C-C coupling to produce C_(2+)products.This work provides an efficient strategy to construct highly active reaction interfaces for industrial-scale electrochemical CO_(2)RR.
基金Y.C.and J.C.are contributed equally to the paper.Project supported by the National Natural Science Foundation of China (U19A2017)the Fundamental Research Funds for the Central South University and the Australian Research Council (DP180100731 and DP180100568)。
文摘The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.
基金financially supported by the National Natural Science Foundation of China (U2032157)the Natural Science Foundation of Jiangsu Province (BK20201425)。
文摘The growth of electrochemically inert segregation layers on the surface of solid oxide fuel cell cathodes has become a bottleneck restricting the development of perovskite-structured oxygen reduction catalysts.Here,we report a new discovery in which enriched Ba and Fe ions on the near-surface of Nd_(1/2)Ba_(1/2)Co_(1/3)Fe_(1/3)Mn_(1/3)O_(3-δ)spontaneously agglomerate into dispersed Ba_(5)Fe_(2)O_(8) nanoparticles and maintain a highly active and durable perovskite structure on the surface.This unique surface selfcleaning phenomenon is related to the low average potential energy of Ba_(5)Fe_(2)O_(8),which is grown on the near-surface layer.The electrochemically inert Ba_(5)Fe_(2)O_(8) segregation layer on the near-surface of the perovskite catalyst achieves self-cleaning by regulating the formation energy of enriched metal oxides.This self-cleaned perovskite surface exhibits an ultrafast oxygen exchange rate,high catalytic activity for the oxygen reduction reaction,and good adaptability to the actual working conditions of solid oxide fuel cell stacks.This study paves a new way for overcoming the stubborn problem of perovskite catalyst surface deactivation and enriches the scientific knowledge of surface catalysis.
基金supported by the Australian Research Council Australian Laureate Fellowship(No.FL200100049)the support of Natural Science Foundation for Young Scholars of Jiangsu Province(No.BK20220879)+1 种基金National Natural Science Foundation for Young Scholars of China(No.22209072)Monash University for a PhD scholarship as part of the university support for establishment of the ARC Research Hub for Energy-efficient Separation(H170100009)。
文摘Metal-air batteries face a great challenge in developing efficient and durable low-cost oxygen reduction reaction(ORR)electrocatalysts.Single-atom iron catalysts embedded into nitrogen doped carbon(Fe-N-C)have emerged as attractive materials for potential replacement of Pt in ORR,but their catalytic performance was limited by the symmetrical electronic structure distribution around the single-atom Fe site.Here,we report our findings in significantly enhancing the ORR performance of Fe-N-C by moderate Fe_(2)O_(3) integration via the strong electronic interaction.Remarkably,the optimized catalyst(M-Fe_(2)O_(3)/Fe_(SA)@NC)exhibits excellent activity,durability and good tolerance to methanol,outperforming the benchmark Pt/C catalyst.When M-Fe_(2)O_(3)/Fe_(SA)@NC catalyst was used in a practical zinc-air battery assembly,peak power density of 155 mW cm^(-2)and specific capacity of 762 mA h g_(Zn)^(-1)were achieved and the battery assembly has shown superior cycling stability over a period of 200 h.More importantly,theoretical studies suggest that the introduction of Fe_(2)O_(3) can evoke the crystal field alteration and electron redistribution on single Fe atoms,which can break the symmetric charge distribution of Fe-N_(4) and thereby optimize the corresponding adsorption energy of intermediates to promote the O_(2)reduction.This study provides a new pathway to promote the catalytic performance of single-atom catalysts.
基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIT) (RS-2023-00210114)supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2021R1C1C1004264 and NRF2021R1A4A1032114)+1 种基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIT) (NRF-2022R1A4A1019296)supported by the National R&D Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (2021M3D1A2051636)。
文摘Mixed metal oxide(MMO) represents a critical class of materials that can allow for obtaining a dynamic interface between its components:reduced metal and its metal oxide counterpart during an electrocatalytic reaction.Here,a synthetic method utilizing a MOF-derived micro/mesoporous carbon as a template to prepare sub-2 nm MMO catalysts for CO_(2) electro reduction is reported.Starting from the zeolite imidazolate framework(ZIF-8),the pyrolyzed derivatives were used to synthesize sub-2 nm Pd-Ni MMO with different compositions.The Ni-rich(Pd_(20)-Ni_(80)/ZC) catalyst exhibits unexpectedly superior performance for CO production with an improved Faradaic efficiency(FE) of 95.3% at the current density of 200 mA cm^(-2) at-0.56 V vs.reversible hydrogen electrode(RHE) compared to other Pd-Ni compositions.X-ray photoelectron spectroscopy(XPS) analysis confirms the presence of Ni^(2+) and Pd^(2+) in all compositions,demonstrating the presence of MMO.Density functional theory(DFT) calculation reveals that the lower CO binding energy on the surface of the Pd_(20)-Ni_(80) cluster eases CO desorption,thus increasing its production.This work provides a general synthetic strategy for MMO electrocatalysts and can pave a new way for screening multimetallic catalysts with a dynamic electrochemical interface.
基金Australian Centre for Neutron ScatteringAustralian Nuclear Science and Technology Organisation,Grant/Award Number:MI8046+1 种基金Max Planck-POSTECH-Hsinchu Center for Complex Phase MaterialsHigh-Performance Computing Center of Nanjing Tech University。
文摘Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic performance and electrochemical behavior of complex metal oxides,especially perovskite oxides,is rarely reported.Here,the inorganic perovskite oxide Ag-doped(La_(0.8)Sr_(0.2))_(0.95)Ag_(0.05)MnO_(3-δ)(LSA0.05M)is reported as an efficient electrocatalyst for ECR to CO for the first time,which exhibits a Faradaic efficiency(FE)of 84.3%,a remarkable mass activity of 75Ag^(-1)(normalized to the mass of Ag),and stability of 130 h at a moderate overpotential of 0.79 V.The LSA0.05M catalyst experiences structure reconstruction during ECR,creating the in operando-formed interface between the perovskite and the evolved Ag phase.The evolved Ag is uniformly distributed with a small particle size on the perovskite surface.Theoretical calculations indicate the reconstruction of LSA0.05M during ECR and reveal that the perovskite-Ag interface provides adsorption sites for CO_(2) and accelerates the desorption of the*CO intermediate to enhance ECR.This study presents a novel high-performance perovskite catalyst for ECR andmay inspire the future design of electrocatalysts via the in operando formation of metal-metal oxide interfaces.
文摘Crystal growth of tungsten during hydrogen reduction of tungsten oxide (WO3) to prepare coarse grain tungsten powder at high temperature (950 ℃) was studied. The phase composition and morphologies of products were investigated by means of XRD and SEM. The results show that the reduction sequence of hydrogen reduction of WO3 is WO3→WO2.9→W18O49→WO2→W. The step of WO2→W is the critical step which determines the grain size of tungsten powder. The partial pressure (pH2O/pH2) of H2O within powder layer shows strong effect on the nucleation and grain growth of tungsten. By increasing the pH2O/pH2 within powder layer, well-developed coarse grain tungsten powder with particle size above 15 μm is obtained. After carburizing, the powder can be used to produce ultra-coarse grain cemented carbide with grain size above 5 μm.
基金The University of Adelaide for Early Career Researcher Seed Funding(15128587)the University of Electronic Science and Technology of China(UESTC)for Startup funding(A1098531023601264)the National Natural Science Foundation of China(NSFC 22102018 and 52171201)。
文摘Electrocatalytic oxygen reduction reaction (ORR) via two-electron pathway is a promising approach to decentralized and on-site hydrogen peroxide (H_(2)O_(2)) production beyond the traditional anthraquinone process.In recent years,electrochemical H_(2)O_(2) production in acidic media has attracted increasing attention owing to its stronger oxidizing capacity,superior stability,and higher compatibility with various applications.Here,recent advances of H_(2)O_(2) electrosynthesis in acidic media are summarized.Specifically,fundamental aspects of two-electron ORR mechanism are firstly presented with an emphasis on the pH effect on catalytic performance.Major categories of promising electrocatalysts are then reviewed,including noble-metal-based materials,non-noble-metal single-atom catalysts,non-noblemetal compounds,and metal-free carbon-based materials.The innovative development of electrochemical devices and in situ/on-site application of electrogenerated H_(2)O_(2) are also highlighted to bridge the gap between laboratory-scale fundamental research and practically relevant H_(2)O_(2) electrosynthesis.Finally,critical perspectives on present challenges and promising opportunities for future research are provided.
基金financial support from the Walter Benjamin Programme of the Deutsche Forschungsgemeinschaft(No.468209039)the financial support from Capes-Humboldt(No.88881.512949/2020-01)the financial support from the Heisenberg Programme of the Deutsche Forschungsgemeinschaft(SP16662/1)。
文摘Steel production causes a third of all industrial CO_(2) emissions due to the use of carbon-based substances as reductants for iron ores,making it a key driver of global warming.Therefore,research efforts aim to replace these reductants with sustainably produced hydrogen.Hydrogen-based direct reduction(HyDR)is an attractive processing technology,given that direct reduction(DR)furnaces are routinely operated in the steel industry but with CH_(4) or CO as reductants.Hydrogen diffuses considerably faster through shaft-furnace pellet agglomerates than carbon-based reductants.However,the net reduction kinetics in HyDR remains extremely sluggish for high-quantity steel production,and the hydrogen consumption exceeds the stoichiometrically required amount substantially.Thus,the present study focused on the improved understanding of the influence of spatial gradients,morphology,and internal microstructures of ore pellets on reduction efficiency and metallization during HyDR.For this purpose,commercial DR pellets were investigated using synchrotron high-energy X-ray diffraction and electron microscopy in conjunction with electron backscatter diffraction and chemical probing.Revealing the interplay of different phases with internal interfaces,free surfaces,and associated nucleation and growth mechanisms provides a basis for developing tailored ore pellets that are highly suited for a fast and efficient HyDR.
文摘The hydrogen reduction of tungsten oxides WO_(2.90),W_(20)O_(58) and WO_3 were directly studied using high temperature X-ray diffraction analysis.The differences between tetragonal WO_(2.90) and monoclinic W_(20)O_(58) were discussed.Pure β-W was obtained from oxide WO_(2.90),while there appears small amount of WO_2 during the reduction of W_(20)O_(58) to β-W.
基金the financial support of the National Natural Science Foundation of China (Nos. 21277091 and 51472159)the State Key Program of National Natural Science Foundation of China (No. 21436007)+1 种基金the Key Basic Research Projects of Science and Technology Commission of Shanghai (No. 14JC1403100)the Chenxing-SMG Young Scholar Project of Shanghai Jiao Tong University
文摘The Earth’s sustainable development is threatened by the increasing atmospheric COlevel which can be attributed to the imbalance of COdue to the rapid consumption of fossil fuels caused by human activities and the slow absorption and conversion of COby nature. One of the efficient methods for reconstructing the balance of COshould involve the rapid conversion of COinto fuels and chemicals.The hydrogenation of COwith gaseous hydrogen is currently considered to be the most commercially feasible synthetic route, however, the supply of safe and economical hydrogen sources poses a significant challenge to up-scaling application. Direct utilization of hydrogen from dissociation of water, the most abundant, cheap and clean hydrogen resource, for the reduction of COwould be one of the most promising approaches for COutilization. This paper provides an overview of the current advances in research on highly efficient reduction of COor NaHCO, a representative compound of CO, into formic acid/formate by in situ hydrogen from water dissociation with a metal/metal oxide redox cycle under mild hydrothermal conditions.
基金Funded by the Key Program Project of the National Natural Science Foundation of China (No.50234040)the Major Project of the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KCCX1-SW-22)
文摘The ultra-fine chromic oxide powder was prepared by a novel gas-solid reduction reaction.Na2CrO4 was firstly reduced with hydrogen at 400-600 ℃.The obtained reduction products,mainly the mixture of NaCrO2 and sodium hydroxide(NaOH),were converted into chromic oxide through hydrolysis followed by calcination.The obtained chromic oxide product was characterized by powder X-ray diffraction(XRD) and SEM.The results show that the hydrolysis process of sodium chromite is the key step and lower reduction temperature helps intensify the hydrolysis process.
文摘The hydrogen reduction of tungsten oxides WO_(272)and WO_2 were studied directly using high-temperature X-ray diffraction analysis,The pure β-W was obtained from the reduction of WO_(272)The transformation of β-W to x-W was also studied in both hydrogen and nitrogen.The forming condition of β-W from WO_2 was discussed.Finally.a complete schematic diagram of reduction of tungsten oxides was given in this paper.