Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within th...Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within this field. Molten salt CO_2 capture and electrochemical transformation(MSCC-ET) process is a desirable method due to a high CO_2 solubility, a wide potential window of molten salts and easily-controlled electrode reactions. Generally, electro-splitting CO_2 in molten salts begins with CO_2 absorption reactions to form CO_3^(2-), which is then followed by the carbon deposition at the cathode and O_2 evolution at the anode. As a result, CO_2 is electro-converted to O_2 and carbon with different morphologies, compositions, microstructures and functional properties. This report introduces the MSCC-ET process, summarizes the reactions occurring in the molten salts and at the electrode surfaces, as well as the morphological variations of the cathodic products. The inert anode materials, cost estimation and scale-up evaluation of the process are then discussed. It is presumed that with a comprehensive understanding of the electrode reactions during electrolysis and the functional properties of carbon materials obtained during CO_2 electro-splitting can provide a foundation for further developing this environmentally friendly process.展开更多
Ammonia is important feedstock for both fertilizer production and carbon-free liquid fuel.Many techniques for ammonia formation have been developed,hoping to replace the industrial energy-intensive Haber-Bosch route.E...Ammonia is important feedstock for both fertilizer production and carbon-free liquid fuel.Many techniques for ammonia formation have been developed,hoping to replace the industrial energy-intensive Haber-Bosch route.Electrochemical synthesis of ammonia in molten salts is one promising alternative method due to the strong solubility of N3- ions,a wide potential window of molten salt electrolytes and tunable electrode reactions.Generally,electrochemical synthesis of ammonia in molten salts begins with the electro-cleavage of N2/hydrogen sources on electrode surfaces,followed by diffusion of N3^-/H^+-containing ions towards each other for NH3 formation.Therefore,the hydrogen sources and molten salt composition will greatly affect the reactions on electrodes and ions diffusion in electrolytes,being critical factors determining the faradaic efficiency and formation rate for ammonia synthesis.This report summarizes the selection criteria for hydrogen sources,the reaction characteristics in various molten salt systems,and the preliminary explorations on the scaling-up synthesis of ammonia in molten salt.The formation rate and faradaic efficiency for ammonia synthesis are discussed in detail based on different hydrogen sources,various molten salt systems,changed electrolysis conditions as well as diverse catalysts.Electrochemical synthesis of ammonia might be further enhanced by optimizing the molten salt composition,using electrocatalysts with well-defined composition and microstructure,and innovation of novel reaction mechanism.展开更多
The increasing demands of hydrogen and the recent discovery of large reserves of methane have prompted the conversion of methane to hydrogen.The challenges raised by intensive CO_(2) emission from the traditional conv...The increasing demands of hydrogen and the recent discovery of large reserves of methane have prompted the conversion of methane to hydrogen.The challenges raised by intensive CO_(2) emission from the traditional conversion of methane have provoked emission-free hydrogen production from methane.The catalytic decomposition of methane(CDM) to produce hydrogen and advanced carbon hence comes into consideration due to the short process and environmental benignity.Although many researchers have made considerable progress in CDM research on the laboratory scale,CDM is still in its infancy in industrialization.The history of its development,fundamental mechanisms,and recent research progress in catalysts and catalytic systems are herein highlighted.The problems of catalytic interface degradation are reviewed,focusing on deactivation from coke deposition in the CDM process.The introduction of a liquid phase interface which can in-situ remove carbon products provides a new strategy for this process.Furthermore,the challenges and prospects for future research into novel CDM catalysts or catalyst systems are included.展开更多
Implementation of non-precious electrocatalysts is key-enabling for water electrolysis to relieve challenges in energy and environmental sustainability. Self-supporting Ni-V2O3 electrodes consisting of nanostrip-like ...Implementation of non-precious electrocatalysts is key-enabling for water electrolysis to relieve challenges in energy and environmental sustainability. Self-supporting Ni-V2O3 electrodes consisting of nanostrip-like V2O3 perpendicularly anchored on Ni meshes are herein constructed via the electrochemical reduction of soluble NaVO3 in molten salts for enhanced electrocatalytic hydrogen evolution. Such a special configuration in morphology and composition creates a well confined interface between Ni and V2O3. Experimental and Density-Functional-Theory results confirm that the synergy between Ni and V2O3 accelerates the dissociation of H2O for forming hydrogen intermediates and enhances the combination of H*for generating H2.展开更多
Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environmental and energy sustainability.We herein demonstrate a molten salt thermoelectrolysis of rice husks(RHs)mainl...Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environmental and energy sustainability.We herein demonstrate a molten salt thermoelectrolysis of rice husks(RHs)mainly consisting of organic mass and biosilica to achieve high-efficiency and upgraded utilization of both Si and C in RHs.By coupling pyrolysis of organic mass with electrochemical reduction of silica in molten salts,the thermoelectrolysis of RHs in molten CaCl_(2)-NaCl at 800℃ refines the RHs and acidleached RHs to SiC nanowire/C(SiC-NW/C)and Si nanoparticle/C(Si-NP/C),respectively.The present study highlights the molten salt thermoelectrolysis for reclamation of biomass wastes in an affordable and controllable manner.展开更多
Carbon contamination and the formation of low-valence oxides limit the preparation of refractory metals by molten salt electrolysis.In this paper,a liquid Zn cathode is adopted for the electrochemical reduction of sol...Carbon contamination and the formation of low-valence oxides limit the preparation of refractory metals by molten salt electrolysis.In this paper,a liquid Zn cathode is adopted for the electrochemical reduction of soluble K2CrO4 to metallic Cr in CaCl2-KCl molten salt.It is found that CrO4^2-can be directly electrochemically reduced to Cr via a six-electron-transfer step and low-valence Cr oxides is hardly produced.The reduction rate is obviously increased from 16.7 mgCrh^-1cm^-2 on the solid Mo cathode to58.7 mgCrh-1cm-2on liquid Zn cathode.The electrodeposited Cr is distributed in liquid Zn cathode.Carbon contamination is effectively avoided due to the negligible solubility of carbon in the liquid Zn cathode.Furthermore,Cr can be effectively separated and enriched to the bottom of liquid Zn under supergravity field,realizing the efficient acquisition of metallic Cr and recycling of liquid Zn.The method herein provides a promising route for the preparation of refractory metals with high-purity by molten salt electrolysis.展开更多
Structural and compositional design of core-shell structure is an effective strategy towards enhanced catalysis.Herein,amorphous MnO2 nanosheets and K+-intercalated layered MnO2 nanosheets are controllably assembled o...Structural and compositional design of core-shell structure is an effective strategy towards enhanced catalysis.Herein,amorphous MnO2 nanosheets and K+-intercalated layered MnO2 nanosheets are controllably assembled over Fe2O3 spindles,in which the MnO2 nanosheets are perpendicularly anchored to the surface of Fe2O3.Such a core shell structure contributes to a high specific surface area and abundant pore channels on the surface of catalysts.In addition,the existence of K+provides large numbers of basic sites and restrains the formation of unpleasant(Fe1-xMnx)3O4.Benefiting from the merits in structure and composition,CO adsorption is enhanced and remaining time of intermediates is prolonged on the surfaces of catalysts during the Fischer–Tropsch synthesis(FTS),facilitating to the formation of active iron carbides and C–C coupling reactions.Resultantly,the Fe2O3@K+-Mn O2 shows both a high CO conversion of 82.3%and a high C5+ selectivity of 73.1%.The present study provides structural and compositional rationales on design high-performance catalysts towards FTS.展开更多
Activation of oxygen over non-precious materials has been an imperative task to develop efficient electrochemical energy storage and conversion such as fuel cells and metal-air batteries.Herein,a molten salt electroch...Activation of oxygen over non-precious materials has been an imperative task to develop efficient electrochemical energy storage and conversion such as fuel cells and metal-air batteries.Herein,a molten salt electrochemical modulation of metal-nitrogen-carbon based compounds(M–N–C)is achieved.By electrochemical treatment of polydopamine-coated NiCo_(2)O_(4)(NiCo_(2)O_(4)@PDA)in molten Li_(2)CO_(3)-Na_(2)CO_(3)-K_(2)CO_(3)at 500℃,Ni/Co bimetal-nitrogen-carbon catalyst(denoted as Ni/Co@NC)consisting of Ni-Co nanoparticles anchoring on porous nitrogen-doped carbon is constructed and evaluated as electrocatalysts towards the oxygen reduction reaction(ORR).Experimental and calculation results confirm that alloying of Ni-Co and nitrogen doping to carbon enhances the rate-determining transformation of*OH intermediate during ORR.The Ni/Co@NC hence shows an ORR activity comparable with the commercial Pt/C.展开更多
基金funding support from the National Natural Science Foundation of China (51722404 and 51674177)
文摘Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within this field. Molten salt CO_2 capture and electrochemical transformation(MSCC-ET) process is a desirable method due to a high CO_2 solubility, a wide potential window of molten salts and easily-controlled electrode reactions. Generally, electro-splitting CO_2 in molten salts begins with CO_2 absorption reactions to form CO_3^(2-), which is then followed by the carbon deposition at the cathode and O_2 evolution at the anode. As a result, CO_2 is electro-converted to O_2 and carbon with different morphologies, compositions, microstructures and functional properties. This report introduces the MSCC-ET process, summarizes the reactions occurring in the molten salts and at the electrode surfaces, as well as the morphological variations of the cathodic products. The inert anode materials, cost estimation and scale-up evaluation of the process are then discussed. It is presumed that with a comprehensive understanding of the electrode reactions during electrolysis and the functional properties of carbon materials obtained during CO_2 electro-splitting can provide a foundation for further developing this environmentally friendly process.
基金the funding support from the National Natural Science Foundation of China(51722404,51674177,51804221 and 91845113)the National Key R&D Program of China(2018YFE0201703)the China Postdoctoral Science Foundation(2018M642906 and 2019T120684)。
文摘Ammonia is important feedstock for both fertilizer production and carbon-free liquid fuel.Many techniques for ammonia formation have been developed,hoping to replace the industrial energy-intensive Haber-Bosch route.Electrochemical synthesis of ammonia in molten salts is one promising alternative method due to the strong solubility of N3- ions,a wide potential window of molten salt electrolytes and tunable electrode reactions.Generally,electrochemical synthesis of ammonia in molten salts begins with the electro-cleavage of N2/hydrogen sources on electrode surfaces,followed by diffusion of N3^-/H^+-containing ions towards each other for NH3 formation.Therefore,the hydrogen sources and molten salt composition will greatly affect the reactions on electrodes and ions diffusion in electrolytes,being critical factors determining the faradaic efficiency and formation rate for ammonia synthesis.This report summarizes the selection criteria for hydrogen sources,the reaction characteristics in various molten salt systems,and the preliminary explorations on the scaling-up synthesis of ammonia in molten salt.The formation rate and faradaic efficiency for ammonia synthesis are discussed in detail based on different hydrogen sources,various molten salt systems,changed electrolysis conditions as well as diverse catalysts.Electrochemical synthesis of ammonia might be further enhanced by optimizing the molten salt composition,using electrocatalysts with well-defined composition and microstructure,and innovation of novel reaction mechanism.
基金the funding support from the National Natural Science Foundation of China(51722404,51674177,51804221 and 91845113)the National Key R&D Program of China(2018YFE0201703)+2 种基金the China Postdoctoral Science Foundation(2018M642906 and 2019T120684)the Fundamental Research Funds for the Central Universities(2042019kf0230)the Hubei Provincial Natural Science Foundation of China(2019CFA065)。
文摘The increasing demands of hydrogen and the recent discovery of large reserves of methane have prompted the conversion of methane to hydrogen.The challenges raised by intensive CO_(2) emission from the traditional conversion of methane have provoked emission-free hydrogen production from methane.The catalytic decomposition of methane(CDM) to produce hydrogen and advanced carbon hence comes into consideration due to the short process and environmental benignity.Although many researchers have made considerable progress in CDM research on the laboratory scale,CDM is still in its infancy in industrialization.The history of its development,fundamental mechanisms,and recent research progress in catalysts and catalytic systems are herein highlighted.The problems of catalytic interface degradation are reviewed,focusing on deactivation from coke deposition in the CDM process.The introduction of a liquid phase interface which can in-situ remove carbon products provides a new strategy for this process.Furthermore,the challenges and prospects for future research into novel CDM catalysts or catalyst systems are included.
基金the funding support from the National Natural Science Foundation of China(51722404,51674177,51804221 and 91845113)the National Key R&D Program of China(2018YFE0201703)+2 种基金the China Postdoctoral Science Foundation(2018M642906 and 2019T120684)the Fundamental Research Funds for the Central Universities(2042017kf0200)the Hubei Provincial Natural Science Foundation of China(2019CFA065)。
文摘Implementation of non-precious electrocatalysts is key-enabling for water electrolysis to relieve challenges in energy and environmental sustainability. Self-supporting Ni-V2O3 electrodes consisting of nanostrip-like V2O3 perpendicularly anchored on Ni meshes are herein constructed via the electrochemical reduction of soluble NaVO3 in molten salts for enhanced electrocatalytic hydrogen evolution. Such a special configuration in morphology and composition creates a well confined interface between Ni and V2O3. Experimental and Density-Functional-Theory results confirm that the synergy between Ni and V2O3 accelerates the dissociation of H2O for forming hydrogen intermediates and enhances the combination of H*for generating H2.
基金the funding support from the National Natural Science Foundation of China(51722404,51674177,51804221 and 91845113)the National Key R&D Program of China(2018YFE0201703)+2 种基金the China Postdoctoral Science Foundation(2018M642906 and 2019T120684)the Fundamental Research Funds for the Central Universities(2042017kf0200)the Hubei Provincial Natural Science Foundation of China(2019CFA065)。
文摘Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environmental and energy sustainability.We herein demonstrate a molten salt thermoelectrolysis of rice husks(RHs)mainly consisting of organic mass and biosilica to achieve high-efficiency and upgraded utilization of both Si and C in RHs.By coupling pyrolysis of organic mass with electrochemical reduction of silica in molten salts,the thermoelectrolysis of RHs in molten CaCl_(2)-NaCl at 800℃ refines the RHs and acidleached RHs to SiC nanowire/C(SiC-NW/C)and Si nanoparticle/C(Si-NP/C),respectively.The present study highlights the molten salt thermoelectrolysis for reclamation of biomass wastes in an affordable and controllable manner.
基金supported by the National Natural Science Foundation of China (51804221, 51474200, 91845113)Project funded by China Postdoctoral Science Foundation (2018M642906)the Fundamental Research Funds for the Central Universities (FRF-TP18-010B1)
文摘Carbon contamination and the formation of low-valence oxides limit the preparation of refractory metals by molten salt electrolysis.In this paper,a liquid Zn cathode is adopted for the electrochemical reduction of soluble K2CrO4 to metallic Cr in CaCl2-KCl molten salt.It is found that CrO4^2-can be directly electrochemically reduced to Cr via a six-electron-transfer step and low-valence Cr oxides is hardly produced.The reduction rate is obviously increased from 16.7 mgCrh^-1cm^-2 on the solid Mo cathode to58.7 mgCrh-1cm-2on liquid Zn cathode.The electrodeposited Cr is distributed in liquid Zn cathode.Carbon contamination is effectively avoided due to the negligible solubility of carbon in the liquid Zn cathode.Furthermore,Cr can be effectively separated and enriched to the bottom of liquid Zn under supergravity field,realizing the efficient acquisition of metallic Cr and recycling of liquid Zn.The method herein provides a promising route for the preparation of refractory metals with high-purity by molten salt electrolysis.
基金funding support from the National Natural Science Foundation of China (51722404, 51674177, 91845113 and 51804221)the “1000-Youth Talents Plan”+3 种基金the Fundamental Research Funds for the Central Universities (2042017kf0200)National Key R&D Program of China (2018YFE0201703)the China Postdoctoral Science Foundation (2018M642906 and 2019T120684)Hubei Provincial Natural Science Foundation of China (2019CFA065)。
文摘Structural and compositional design of core-shell structure is an effective strategy towards enhanced catalysis.Herein,amorphous MnO2 nanosheets and K+-intercalated layered MnO2 nanosheets are controllably assembled over Fe2O3 spindles,in which the MnO2 nanosheets are perpendicularly anchored to the surface of Fe2O3.Such a core shell structure contributes to a high specific surface area and abundant pore channels on the surface of catalysts.In addition,the existence of K+provides large numbers of basic sites and restrains the formation of unpleasant(Fe1-xMnx)3O4.Benefiting from the merits in structure and composition,CO adsorption is enhanced and remaining time of intermediates is prolonged on the surfaces of catalysts during the Fischer–Tropsch synthesis(FTS),facilitating to the formation of active iron carbides and C–C coupling reactions.Resultantly,the Fe2O3@K+-Mn O2 shows both a high CO conversion of 82.3%and a high C5+ selectivity of 73.1%.The present study provides structural and compositional rationales on design high-performance catalysts towards FTS.
基金the funding support from the National Key R&D Program of China(2018YFE0201703)the Fundamental Research Funds for the Central Universities(2042022kf1174)。
文摘Activation of oxygen over non-precious materials has been an imperative task to develop efficient electrochemical energy storage and conversion such as fuel cells and metal-air batteries.Herein,a molten salt electrochemical modulation of metal-nitrogen-carbon based compounds(M–N–C)is achieved.By electrochemical treatment of polydopamine-coated NiCo_(2)O_(4)(NiCo_(2)O_(4)@PDA)in molten Li_(2)CO_(3)-Na_(2)CO_(3)-K_(2)CO_(3)at 500℃,Ni/Co bimetal-nitrogen-carbon catalyst(denoted as Ni/Co@NC)consisting of Ni-Co nanoparticles anchoring on porous nitrogen-doped carbon is constructed and evaluated as electrocatalysts towards the oxygen reduction reaction(ORR).Experimental and calculation results confirm that alloying of Ni-Co and nitrogen doping to carbon enhances the rate-determining transformation of*OH intermediate during ORR.The Ni/Co@NC hence shows an ORR activity comparable with the commercial Pt/C.
