The electrical conductivity of NaF-AlF3-CaF2-Al2O3-ZrO2 system was studied by a tube-type cell with fixed cell constant. The results show that the electrical conductivity of NaF-AlF3-3%Al2O3-3%CaF2-ZrO2 molten salt sy...The electrical conductivity of NaF-AlF3-CaF2-Al2O3-ZrO2 system was studied by a tube-type cell with fixed cell constant. The results show that the electrical conductivity of NaF-AlF3-3%Al2O3-3%CaF2-ZrO2 molten salt system decreases with increase of ZrO2 content in an interval of 0-5%. The increase of 1%ZrO2 results in a corresponding electrical conductivity decrease of 0.02 S/cm, and the equivalent conductivity increases with the increase of molar ratio of NaF to AlF3. When the temperature increases by 1 °C, the electrical conductivity increases by 0.004 S/cm. At last, the regression equations of electrical conductivity relative to temperature and ZrO2 are obtained by quadratic regression analysis.展开更多
The NaF-CaF_2 system has been studied by molecular dynamics simulation.The pair correlation functions between cations and anions and the bond angle distributions of cation and anion triplets have been obtained.The bri...The NaF-CaF_2 system has been studied by molecular dynamics simulation.The pair correlation functions between cations and anions and the bond angle distributions of cation and anion triplets have been obtained.The bridging and complexing in the system are discussed based on the pair correlation functions and bond angle distributions.The results simulated show that the F^- ions around a Ca^(2+)ion do not form tetrahedron coordination,so some of small complexing clusters such as CaF_4^(2-)are hardly found.A possible structure of F^- ions around Ca^(2+)ions is that three Ca^(2+)ions constitute an equilateral triangle through three Ca-F-Ca bridges and two F^- ions are located over and under the center of the right triangle,respectively.Meanwhile,on the outside of the triangle,every Ca^(2+)ion has other two F^- ions as its neighbors.展开更多
Carbon-based materials have been widely applied for pollutant removal relying on their rich pore structure,functional groups,chemical stability,and expandability.However,the traditional manufacturing process of carbon...Carbon-based materials have been widely applied for pollutant removal relying on their rich pore structure,functional groups,chemical stability,and expandability.However,the traditional manufacturing process of carbon materials based on organic compounds pyrolysis is high energy-consuming and high-emission,which is not conducive to addressing the climate crisis and achieving the goal of carbon neutrality.Molten salt electrolysis technology enables the direct capture and reduction of CO_(2)to produce solid carbon,resulting in significant environmental benefits while achieving carbon emissions reduction.The molten salt also has a purification function,enabling the production of high-purity carbon materials.The kinetics of the electrochemical reduction process can be easily controlled,and the co-reduction of multiple elements provides convenience for the in-situ optimization of carbon material structure and the expansion of its applications.Therefore,this review focuses on the thermodynamics&kinetics processes of molten salt capture and electrochemical reduction of CO_(2)to prepare carbon materials.It further reviews the recent research progress on the preparation of carbon materials for pollutant removal based on molten salt electrochemical processes for the first time.Finally,we analyze the advantages and challenges of the current molten salt electrochemical processes and offers prospects for future research directions.展开更多
Direct utilization of co-existed ferrous oxide(FeO)dust in CO_(2)flue gas from the steel industry to product value-added materials is yet to be established.Inspired by the form of CaO-CaCO_(3)as natural carbon cycle a...Direct utilization of co-existed ferrous oxide(FeO)dust in CO_(2)flue gas from the steel industry to product value-added materials is yet to be established.Inspired by the form of CaO-CaCO_(3)as natural carbon cycle and the high oxide dissolution capacity of molten salts,CaO is herein introduced into the affordable molten NaCl-CaCl_(2)-FeO salt to generate CO_(3)^(2-)through an efficient capture of CO_(2).The subsequent coelectrolysis of FeO and CO_(3)^(2-)successfully produces cathodic Fe-encapsulated carbon nanotubes(Fe@CNT)with enhanced energy efficiency(current efficiency of 83.1%for CO_(2)reduction and energy consumption of 22.49 kWh kg^(1)for Fe@CNT generation).The in-situ capture of CO_(2)by O^(2)generated from the electro-deoxidation of FeO bridges the electrolysis of CO_(2)and FeO,rendering the enhanced current efficiency of the co-electrolysis and template-free generation of Fe@CNT.When evaluated as functional materials for electromagnetic wave absorption,the Fe@CNT integrates dielectric loss of CNT and electromagnetic loss from Fe.The Fe well-defined in CNT induces the synergistic loss and further improves the impedance matching,resulting in excellent electromagnetic wave absorption performance.The coelectrolysis establishes a promising strategy for converting CO_(2)into highly functional materials directly from CO_(2)-containing flue gas from steel industrial without dust removal.展开更多
One-dimensional titanium dioxide(TiO_(2))whiskers with controllable aspect ratios were synthesized by molten salt method adopting anatase TiO_(2)nanoparticles as precursor,sodium chloride(NaCl)and dibasic sodium phosp...One-dimensional titanium dioxide(TiO_(2))whiskers with controllable aspect ratios were synthesized by molten salt method adopting anatase TiO_(2)nanoparticles as precursor,sodium chloride(NaCl)and dibasic sodium phosphate(Na_(2)HPO_(4))as medium.The particle size of TiO_(2)nanoparticles and ratio of precursor and medium that can help to generate high aspect ratio TiO_(2)whiskers were studied and selected.Light-colored antimony-doped tin oxide@titanium dioxide(ATO@TiO_(2))conductive whiskers were prepared by coating ATO on TiO_(2)whiskers through coprecipitation then.Finally,the ATO@TiO_(2)light-colored conductive whiskers were dispersed in polyacrylonitrile(PAN)to fabricate light-colored conductive fibers.The experimental results show that the ATO@TiO_(2)whiskers exhibits ideal whiteness and conductivity with 65.5 Wb and 106Ω·cm,respectively,and the resistivity of conductive fibers was 6.07×10^(6)Ω·cm with 15wt%whisker content.展开更多
Lithium-carbon dioxide(Li-CO_(2))batteries using high ion-conductive inorganic molten salt electrolytes have recently attracted much attention due to the high energy density and potential application of carbon neutral...Lithium-carbon dioxide(Li-CO_(2))batteries using high ion-conductive inorganic molten salt electrolytes have recently attracted much attention due to the high energy density and potential application of carbon neutrality.However,the poor Li-ion conductivity of the molten-salt electrolytes at room temperature(RT)makes these batteries lose most of their capacity and power as the temperature falls below 80℃.Here,inspired by the greenhouse effect,we report an RT molten salt Li-CO_(2)battery where solar energy can be efficiently harvested and converted into heat that is further localized on the cathode consisting of plasmonic ruthenium(Ru)catalysts and Li_(2)CO_(3)-based products via a greenhouse-like phenomenon.As a result,the solar-driven molten salt Li-CO_(2)battery demonstrates a larger full discharge/charge capacity of 9.5 mA h/8.1 mA h,and a longer cycle lifespan of 250 cycles at 500 mA/g with a limited capacity of 500 mA h/g at RT than the molten salt Li-CO_(2)battery at 130℃.Notably,the average temperature of the cathode increases by 8℃ after discharge to 0.75 mA h,which indicates the infrared radiation from Ru catalysts can be effectively suppressed by discharged Li_(2)CO_(3)-based products.This battery technology paves the way for developing low-temperature molten salt energy storage devices.展开更多
A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patt...A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patterns showed that single phase LaMn0.8Fe0.2O3 with good crystallinity was syn‐thesized at 450℃ after 4 h. Transmission electron microscope images exhibited that the LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h possessed a porous spherical morphology com‐posed of aggregated nanocrystallites. Field emission scanning electron microscope images indicated that the growth of the porous LaMn0.8Fe0.2O3 microspheres has two stages. SEM pictures showed that a higher calcination temperature than 450？？ had an adverse effect on the formation of a po‐rous spherical structure. The LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h displayed a high BET surface area of 55.73 m2/g with a pore size of 9.38 nm. Fourier transform infrared spectra suggested that Sr2＋ions entered the A sites and induced a decrease of the binding energy between Mn and O. The CO conversion with the La1‐xSrxMn0.8Fe0.2O3 （0≤x≤0.6） samples indicated that the La0.4Sr0.6Mn0.8Fe0.2O3 sample had the best catalytic activity and stability. Further analysis by X‐ray photoelectron spectroscopy demonstrated that Sr2＋doping altered the content of Mn4＋ions, oxygen vacancies and adsorbed oxygen species on the surface, which affected the catalytic performance for CO oxidation.展开更多
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
Carbon dioxide（CO2） capture using magnesium oxide（MgO）-based adsorbents at intermediate temperatures has been regarded as a very prospective technology for their relatively high adsorption capacity,low cost, and w...Carbon dioxide（CO2） capture using magnesium oxide（MgO）-based adsorbents at intermediate temperatures has been regarded as a very prospective technology for their relatively high adsorption capacity,low cost, and wide availability. During the past few years, great effort has been devoted to the fabrication of molten salts-modified MgO-based adsorbents. The extraordinary progress achieved by coating with molten salts greatly promotes the COcapture capacity of MgO-based adsorbents. Therefore, we feel it necessary to deliver a timely review on this type of COcapturing materials, which will benefit the researchers working in both academic and industrial areas. In this work, we classified the molten saltsmodified MgO adsorbents into four categories:（1） homogenous molten salt-modified MgO adsorbents,（2） molten salt-modified double salts-based MgO adsorbents,（3） mixed molten salts-modified MgO adsorbents, and（4） molten salts-modified MgO-based mixed oxides adsorbents. This contribution critically reviews the recent developments in the synthetic method, adsorption capacity, reaction kinetics, promotion mechanism, operational conditions and regenerability of the molten salts-modified MgO COadsorbents. The challenges and prospects in this promising field of molten salts-modified MgO COadsorbents in real applications are also briefly mentioned.展开更多
The electrochemical reduction of solid TiO2 directly to solid metal is a promising alternative to the current Kroll process. The present work is aimed at studying the effect of electrolysis voltage on the rate of elec...The electrochemical reduction of solid TiO2 directly to solid metal is a promising alternative to the current Kroll process. The present work is aimed at studying the effect of electrolysis voltage on the rate of electrochemical reduction. The products of electrochemical reduction of TiO2 and Ti2O were examined using the scanning electron microscopy （SEM） and X-ray diffraction （XRD） techniques. The results show that Ti2O was reduced to low valent titanium oxide at 1.5 -1.7 V, which was the result of ionization of oxygen. TiO2 and Ti20 were reduced to titanium metal at 2.1-3.1 V, which was the co-action of ionization of oxygen and calciothermic reduction. The oxygen content decreased rapidly with voltage increasing from 2.1 to 2.6 V, while it changed little from 2.6 to 3.1 V. The optimized cell voltage was 2.6-3.1 V.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
Carbon materials have taken an important role in supercapacitor applications due to their outstanding features of large surface area,low price,and stable physicochemical properties.Considerable research efforts have b...Carbon materials have taken an important role in supercapacitor applications due to their outstanding features of large surface area,low price,and stable physicochemical properties.Considerable research efforts have been devoted to the development of novel synthesis strategy for the preparation of porous carbon materials in recent years.In particular,molten salt strategy represents an emerging and promising method,whereby it has shown great potential in achieving tailored production of porous carbon.It has been proved that the molten salt-assisted production of carbon via the direct carbonization of carbonaceous precursors is an effective approach.Furthermore,with the incorporation of electrochemical technology,molten salt synthesis of porous carbon has become flexible and diversiform.Here,this review focuses on the mainstream molten salt synthesis strategies for the production of porous carbon materials,which includes direct molten salt carbonization process,capture and electrochemical conversion of CO_(2)to value-added carbon,electrochemical exfoliation of graphite to graphene-based materials,and electrochemical etching of carbides to new-type carbide-derived carbon materials.The reaction mechanisms and recent advances for these strategies are reviewed and discussed systematically.The morphological and structural properties and capacitive performances of the obtained carbon materials are summarized to reveal their appealing points for supercapacitor applications.Moreover,the opportunities and challenges of the molten salt synthesis strategy for the preparation of carbon materials are also discussed in this review to provide inspiration to the future researches.展开更多
基金Project (2007CB210305) supported by the National Basic Research Program of ChinaProject (51074045) supported by the National Natural Science Foundation of China
文摘The electrical conductivity of NaF-AlF3-CaF2-Al2O3-ZrO2 system was studied by a tube-type cell with fixed cell constant. The results show that the electrical conductivity of NaF-AlF3-3%Al2O3-3%CaF2-ZrO2 molten salt system decreases with increase of ZrO2 content in an interval of 0-5%. The increase of 1%ZrO2 results in a corresponding electrical conductivity decrease of 0.02 S/cm, and the equivalent conductivity increases with the increase of molar ratio of NaF to AlF3. When the temperature increases by 1 °C, the electrical conductivity increases by 0.004 S/cm. At last, the regression equations of electrical conductivity relative to temperature and ZrO2 are obtained by quadratic regression analysis.
文摘The NaF-CaF_2 system has been studied by molecular dynamics simulation.The pair correlation functions between cations and anions and the bond angle distributions of cation and anion triplets have been obtained.The bridging and complexing in the system are discussed based on the pair correlation functions and bond angle distributions.The results simulated show that the F^- ions around a Ca^(2+)ion do not form tetrahedron coordination,so some of small complexing clusters such as CaF_4^(2-)are hardly found.A possible structure of F^- ions around Ca^(2+)ions is that three Ca^(2+)ions constitute an equilateral triangle through three Ca-F-Ca bridges and two F^- ions are located over and under the center of the right triangle,respectively.Meanwhile,on the outside of the triangle,every Ca^(2+)ion has other two F^- ions as its neighbors.
基金supported by the National Natural Science Foundation of China(Nos.52200143,51979011 and 52276208)the Natural Science Foundation of Hubei Province(No.2024AFB546)the Fundamental Research Funds for Central Public Welfare Research Institutes(Nos.CKSF2023302/CL and CKSF2023314/CL).
文摘Carbon-based materials have been widely applied for pollutant removal relying on their rich pore structure,functional groups,chemical stability,and expandability.However,the traditional manufacturing process of carbon materials based on organic compounds pyrolysis is high energy-consuming and high-emission,which is not conducive to addressing the climate crisis and achieving the goal of carbon neutrality.Molten salt electrolysis technology enables the direct capture and reduction of CO_(2)to produce solid carbon,resulting in significant environmental benefits while achieving carbon emissions reduction.The molten salt also has a purification function,enabling the production of high-purity carbon materials.The kinetics of the electrochemical reduction process can be easily controlled,and the co-reduction of multiple elements provides convenience for the in-situ optimization of carbon material structure and the expansion of its applications.Therefore,this review focuses on the thermodynamics&kinetics processes of molten salt capture and electrochemical reduction of CO_(2)to prepare carbon materials.It further reviews the recent research progress on the preparation of carbon materials for pollutant removal based on molten salt electrochemical processes for the first time.Finally,we analyze the advantages and challenges of the current molten salt electrochemical processes and offers prospects for future research directions.
基金supported by the National Key R&D Program of China(2023YFA1508001)the National Natural Science Foundation of China(22272120 and U2202251)+2 种基金the Fundamental Research Funds for the Central Universities(2042022kf1174)the Hainan Province Science and Technology Special Fund(ZDYF2023SHFZ120 and ZDYF2021SHFZ058)the Research Foundation of Marine Science and Technology Collaborative Innovation Center of Hainan University(XTCX2022HYB01)。
文摘Direct utilization of co-existed ferrous oxide(FeO)dust in CO_(2)flue gas from the steel industry to product value-added materials is yet to be established.Inspired by the form of CaO-CaCO_(3)as natural carbon cycle and the high oxide dissolution capacity of molten salts,CaO is herein introduced into the affordable molten NaCl-CaCl_(2)-FeO salt to generate CO_(3)^(2-)through an efficient capture of CO_(2).The subsequent coelectrolysis of FeO and CO_(3)^(2-)successfully produces cathodic Fe-encapsulated carbon nanotubes(Fe@CNT)with enhanced energy efficiency(current efficiency of 83.1%for CO_(2)reduction and energy consumption of 22.49 kWh kg^(1)for Fe@CNT generation).The in-situ capture of CO_(2)by O^(2)generated from the electro-deoxidation of FeO bridges the electrolysis of CO_(2)and FeO,rendering the enhanced current efficiency of the co-electrolysis and template-free generation of Fe@CNT.When evaluated as functional materials for electromagnetic wave absorption,the Fe@CNT integrates dielectric loss of CNT and electromagnetic loss from Fe.The Fe well-defined in CNT induces the synergistic loss and further improves the impedance matching,resulting in excellent electromagnetic wave absorption performance.The coelectrolysis establishes a promising strategy for converting CO_(2)into highly functional materials directly from CO_(2)-containing flue gas from steel industrial without dust removal.
基金Funded by the National Natural Science Foundation of China(No.51803076)the Natural Science Foundation of Jiangsu Province of China(No.BK20180629)+1 种基金the China Postdoctoral Science Foundation(No.2018M632231)the Key Laboratory of Special Protective Textiles of Ministry of Education(Jiangnan University)(No.TZFH-24-006)。
文摘One-dimensional titanium dioxide(TiO_(2))whiskers with controllable aspect ratios were synthesized by molten salt method adopting anatase TiO_(2)nanoparticles as precursor,sodium chloride(NaCl)and dibasic sodium phosphate(Na_(2)HPO_(4))as medium.The particle size of TiO_(2)nanoparticles and ratio of precursor and medium that can help to generate high aspect ratio TiO_(2)whiskers were studied and selected.Light-colored antimony-doped tin oxide@titanium dioxide(ATO@TiO_(2))conductive whiskers were prepared by coating ATO on TiO_(2)whiskers through coprecipitation then.Finally,the ATO@TiO_(2)light-colored conductive whiskers were dispersed in polyacrylonitrile(PAN)to fabricate light-colored conductive fibers.The experimental results show that the ATO@TiO_(2)whiskers exhibits ideal whiteness and conductivity with 65.5 Wb and 106Ω·cm,respectively,and the resistivity of conductive fibers was 6.07×10^(6)Ω·cm with 15wt%whisker content.
基金supported by the National Natural Science Foundation of China(NSFC,62104099,61921005,62105048,62204117 and 62073299)the Science and Technology Research Program of Chongqing Education Commission(KJQN202100633)+5 种基金the Postdoctoral Science Foundation of China(2021M693768 and 2021M701057)the Key Scientific Research Project in Colleges and Universities of Henan Province,China(21A416001)the Key Laboratory for Special Functional Materials(KEKT2022-06)the Natural Science Foundation of Jiangsu Province(BK20210275 and BK20230498)the support from Jiangsu Province Science Foundation for Youths(BK20210275)National Natural Science Foundation of China(NSFC,62204117)。
文摘Lithium-carbon dioxide(Li-CO_(2))batteries using high ion-conductive inorganic molten salt electrolytes have recently attracted much attention due to the high energy density and potential application of carbon neutrality.However,the poor Li-ion conductivity of the molten-salt electrolytes at room temperature(RT)makes these batteries lose most of their capacity and power as the temperature falls below 80℃.Here,inspired by the greenhouse effect,we report an RT molten salt Li-CO_(2)battery where solar energy can be efficiently harvested and converted into heat that is further localized on the cathode consisting of plasmonic ruthenium(Ru)catalysts and Li_(2)CO_(3)-based products via a greenhouse-like phenomenon.As a result,the solar-driven molten salt Li-CO_(2)battery demonstrates a larger full discharge/charge capacity of 9.5 mA h/8.1 mA h,and a longer cycle lifespan of 250 cycles at 500 mA/g with a limited capacity of 500 mA h/g at RT than the molten salt Li-CO_(2)battery at 130℃.Notably,the average temperature of the cathode increases by 8℃ after discharge to 0.75 mA h,which indicates the infrared radiation from Ru catalysts can be effectively suppressed by discharged Li_(2)CO_(3)-based products.This battery technology paves the way for developing low-temperature molten salt energy storage devices.
基金supported by the National Science Foundation for Young Scientists of China (51202171)~~
文摘A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patterns showed that single phase LaMn0.8Fe0.2O3 with good crystallinity was syn‐thesized at 450℃ after 4 h. Transmission electron microscope images exhibited that the LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h possessed a porous spherical morphology com‐posed of aggregated nanocrystallites. Field emission scanning electron microscope images indicated that the growth of the porous LaMn0.8Fe0.2O3 microspheres has two stages. SEM pictures showed that a higher calcination temperature than 450？？ had an adverse effect on the formation of a po‐rous spherical structure. The LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h displayed a high BET surface area of 55.73 m2/g with a pore size of 9.38 nm. Fourier transform infrared spectra suggested that Sr2＋ions entered the A sites and induced a decrease of the binding energy between Mn and O. The CO conversion with the La1‐xSrxMn0.8Fe0.2O3 （0≤x≤0.6） samples indicated that the La0.4Sr0.6Mn0.8Fe0.2O3 sample had the best catalytic activity and stability. Further analysis by X‐ray photoelectron spectroscopy demonstrated that Sr2＋doping altered the content of Mn4＋ions, oxygen vacancies and adsorbed oxygen species on the surface, which affected the catalytic performance for CO oxidation.
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 Fundamental Research Funds for the Central Universities (2016ZCQ03)Beijing Excellent Young Scholar (2015000026833ZK11)+1 种基金the National Natural Science Foundation of China (51622801, 51572029, and 51308045)the Xu Guangqi grant
文摘Carbon dioxide（CO2） capture using magnesium oxide（MgO）-based adsorbents at intermediate temperatures has been regarded as a very prospective technology for their relatively high adsorption capacity,low cost, and wide availability. During the past few years, great effort has been devoted to the fabrication of molten salts-modified MgO-based adsorbents. The extraordinary progress achieved by coating with molten salts greatly promotes the COcapture capacity of MgO-based adsorbents. Therefore, we feel it necessary to deliver a timely review on this type of COcapturing materials, which will benefit the researchers working in both academic and industrial areas. In this work, we classified the molten saltsmodified MgO adsorbents into four categories:（1） homogenous molten salt-modified MgO adsorbents,（2） molten salt-modified double salts-based MgO adsorbents,（3） mixed molten salts-modified MgO adsorbents, and（4） molten salts-modified MgO-based mixed oxides adsorbents. This contribution critically reviews the recent developments in the synthetic method, adsorption capacity, reaction kinetics, promotion mechanism, operational conditions and regenerability of the molten salts-modified MgO COadsorbents. The challenges and prospects in this promising field of molten salts-modified MgO COadsorbents in real applications are also briefly mentioned.
基金the Postdoctoral Science Foundation of China (No. 20060400409).
文摘The electrochemical reduction of solid TiO2 directly to solid metal is a promising alternative to the current Kroll process. The present work is aimed at studying the effect of electrolysis voltage on the rate of electrochemical reduction. The products of electrochemical reduction of TiO2 and Ti2O were examined using the scanning electron microscopy （SEM） and X-ray diffraction （XRD） techniques. The results show that Ti2O was reduced to low valent titanium oxide at 1.5 -1.7 V, which was the result of ionization of oxygen. TiO2 and Ti20 were reduced to titanium metal at 2.1-3.1 V, which was the co-action of ionization of oxygen and calciothermic reduction. The oxygen content decreased rapidly with voltage increasing from 2.1 to 2.6 V, while it changed little from 2.6 to 3.1 V. The optimized cell voltage was 2.6-3.1 V.
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financially supported by the National Natural Science Foundation of China(Nos.5202205451974181+4 种基金5200415)the Shanghai Rising-Star Program(19QA1403600)the Iron and Steel Joint Research Found of National Natural Science Foundation and China Baowu Steel Group Corporation Limited(U1860203)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(TP2019041)the CAS Interdisciplinary Innovation Team for financial support。
文摘Carbon materials have taken an important role in supercapacitor applications due to their outstanding features of large surface area,low price,and stable physicochemical properties.Considerable research efforts have been devoted to the development of novel synthesis strategy for the preparation of porous carbon materials in recent years.In particular,molten salt strategy represents an emerging and promising method,whereby it has shown great potential in achieving tailored production of porous carbon.It has been proved that the molten salt-assisted production of carbon via the direct carbonization of carbonaceous precursors is an effective approach.Furthermore,with the incorporation of electrochemical technology,molten salt synthesis of porous carbon has become flexible and diversiform.Here,this review focuses on the mainstream molten salt synthesis strategies for the production of porous carbon materials,which includes direct molten salt carbonization process,capture and electrochemical conversion of CO_(2)to value-added carbon,electrochemical exfoliation of graphite to graphene-based materials,and electrochemical etching of carbides to new-type carbide-derived carbon materials.The reaction mechanisms and recent advances for these strategies are reviewed and discussed systematically.The morphological and structural properties and capacitive performances of the obtained carbon materials are summarized to reveal their appealing points for supercapacitor applications.Moreover,the opportunities and challenges of the molten salt synthesis strategy for the preparation of carbon materials are also discussed in this review to provide inspiration to the future researches.
