It is highly desirable to design efficient and stable hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)electrocatalysts for the development of renewable energy technologies.Herein,densit...It is highly desirable to design efficient and stable hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)electrocatalysts for the development of renewable energy technologies.Herein,density functional theory(DFT)calculations were conducted to systematically investigate a series of TMN_(x)O_(4-x)-HTT(TM=Fe,Co,Ni,Ru,Rh,Pd,Ir and Pt;HTT=hexahydroxy tetraazanaphthotetraphene)analogs of two-dimensional(2D)conductive metal-organic frameworks(MOFs)as potential electrocatalysts for the HER,OER and ORR.The thermodynamic and electrochemical stability simulations suggest that these designed catalysts are stable.Remarkably,CoO_(4)-HTT,RhN_(3)O_(1)-HTT and IrN3O1-HTT are predicted to be the most promising catalysts for the HER,OER and ORR,respectively,surpassing the catalytic activity of corresponding benchmark catalysts.The volcano plots were established based on the scaling relationship of adsorption Gibbs free energy of intermediates.The results reveal that regulating combinations of metal active centers and local coordination environments could effectively balance the interaction strength between intermediates and catalysts,thus achieving optimal catalytic activity.Our findings not only opt for the promising HER/OER/ORR electrocatalysts but also guide the design of efficient electrocatalysts based on 2D MOFs materials.展开更多
制备具有氧还原(ORR)与氧释放(OER)双功能催化活性的特殊孔道结构电催化剂是锂氧电池研究的挑战之一。本文以氧化石墨烯、硝酸铁、硝酸镧、柠檬酸为原料,结合溶胶凝胶和水热合成方法,制备出还原氧化石墨烯(RGO)与铁酸镧(LaFeO_3)复合的...制备具有氧还原(ORR)与氧释放(OER)双功能催化活性的特殊孔道结构电催化剂是锂氧电池研究的挑战之一。本文以氧化石墨烯、硝酸铁、硝酸镧、柠檬酸为原料,结合溶胶凝胶和水热合成方法,制备出还原氧化石墨烯(RGO)与铁酸镧(LaFeO_3)复合的双功能催化剂(RGO-LaFeO_3)。X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱和Raman光谱分析结果确认该复合催化剂由纯相钙钛矿结构LaFeO_3和还原氧化石墨烯组成,扫描电子显微镜(SEM)观察到LaFeO_3纳米颗粒均匀地负载在RGO片层表面。锂氧电池测试结果指出,相对于LaFeO_3纳米粒子(NP-LaFeO_3),RGO-LaFeO_3催化剂具有更好的ORR和OER催化活性,归因于RGO特殊的三维导电多孔结构与LaFeO_3纳米粒子的协同催化作用。以RGO-LaFeO_3作为阴极催化剂的锂氧电池在限1000 m Ah?g^(-1)比容量、100 m A?g^(-1)电流密度条件下,可实现36周稳定的充放电循环,展示出良好的应用前景。展开更多
The pyrolysis under inert atmosphere has been widely used for the synthesis of metal containing heteroatoms doped carbon materials, versatile catalysts for various reactions. However, it is difficult to prevent metal ...The pyrolysis under inert atmosphere has been widely used for the synthesis of metal containing heteroatoms doped carbon materials, versatile catalysts for various reactions. However, it is difficult to prevent metal nanoparticles aggregation during pyrolysis process. Herein, we reported the efficient synthesis of nitrogen doped carbon hollow nanospheres with cobalt nanoparticles （Co NP, ca. 10nm in size） distributed uniformly in the shell via pyrolysis of yolk-shell structured Zn-Co-ZIFs@polydopamine （PDA）. PDA acted as both protection layer and carbon source, which successfully prevented the aggregation of cobalt nanoparticles during high-temperature pyrolysis process. The Co NP and N containing carbon （Co NP/NC） hollow nanospheres were active for both oxygen evolution reaction （OER） and oxygen reduction reaction （ORR）, affording overpotential of 430 mV at 10 mA/cm2 for OER in 1 M KOH and comparable half-wave potential to that of Pt/C （0.80V vs RHE） for ORR in 0.1 M KOH. The superior performance of carbon hollow nanospheres for both OER and ORR was mainly attributed to its small metal nanoparticles, N-doping and hollow nanostructure. The protection and confinement effect that originated from PDA coating strategy could be extended to the synthesis of other hollow structured carbon materials, especially the ones with small metal nanoparticles.展开更多
Co-doped perovskite oxide La_(0.4)Sr_(0.6)Co_xMn_(1-x)O_3(x=0, 0.2, 0.4) composites are prepared by sol-gel method utilizing citric acid as chelating agent. These composites show good catalytic activities when tested ...Co-doped perovskite oxide La_(0.4)Sr_(0.6)Co_xMn_(1-x)O_3(x=0, 0.2, 0.4) composites are prepared by sol-gel method utilizing citric acid as chelating agent. These composites show good catalytic activities when tested as catalysts rechargeable lithium-air batteries. In particular, the La_(0.4)Sr_(0.6)Co_(0.4)Mn_(0.6)O_3 shows a lower potential gap. When these samples are tested as catalysts for Li-air batteries at a current density of100 mA g^(-1), the discharge capacities with different La_(0.4)Sr_(0.6)Co_xMn_(1-x)O_3(x=0,0.2, 0.4) catalysts are 5819, 6420, and 7227 mA h g^(-1),respectively. In addition, under a capacity limitation of 1000 mA h g^(-1), the cell using La_(0.4)Sr_(0.6)Co_(0.4)Mn_(0.6)O_3 as catalyst shows good cycling stability up to 46 cycles. The good electrochemical performance suggests that suitable doping of Co in Mn site of La_(0.4)Sr_(0.6)MnO_3 could be a promising route to improve the catalytic activity.展开更多
Electrocatalysis,which involves oxidation and reduction reactions with direct electron transfer,is essential for a variety of clean energy conversion devices.Currently,the vast majority of studies regarding electrocat...Electrocatalysis,which involves oxidation and reduction reactions with direct electron transfer,is essential for a variety of clean energy conversion devices.Currently,the vast majority of studies regarding electrocatalysis reactions focus on strong acidic or alkaline media because of the higher catalytic activity.Nevertheless,some inherent drawbacks,including the corrosive environment,expensive proton exchange membranes,and side effects,are still hard to break through.A sustainably promising way to overcome these shortcomings is to deploy neutral/near-neutral electrolytes for electrocatalysis reactions.Unfortunately,insufficient research in this area due to the lack of attention to related issues has slowed down the development process.In this review,we systematically review the catalytic reaction mechanisms,neutral electrolytes,electrocatalysts,and modification strategies carried out in neutral media on the three most common electrocatalytic reactions,that is,hydrogen evolution reaction,oxygen reduction reaction,and oxygen evolution reaction.Furthermore,the advanced characterization tools for guiding catalyst synthesis and mechanistic studies are also summarized.Eventually,we propose some challenges and perspectives on electrocatalysis reactions in neutral media and hope it will attract more research interest and provide guidance in neutral electrocatalysis.展开更多
Lithium oxygen battery has the highest theoretical capacity among the rechargeable batteries and it can reform energy storage technology if it comes to commercialization. However,many critical challenges,mainly embody...Lithium oxygen battery has the highest theoretical capacity among the rechargeable batteries and it can reform energy storage technology if it comes to commercialization. However,many critical challenges,mainly embody as low charge/discharge round-trip efficiency and poor cycling stability,impede the development of Li-O_2 batteries. The electrolyte decomposition,lithium metal anode corrosion and sluggish oxygen reaction kinetics at cathode are all responsible for poor electrochemical performances.Particularly,the catalytic cathode of Li-O_2 batteries,playing a crucial role to reduce the oxygen during discharging and to decompose discharge products during charging,is regarded as a breakthrough point that has been comprehensive investigated. In this review,the progress and issues of electrolyte,anode and cathode,especially the catalysts used at cathode,are systematically summarized and discussed.Then the perspectives toward the developments of a long life Li-O_2 battery are also presented at last.展开更多
Efficient oxygen electrocatalysts are the key elements of numerous energy storage and conversion devices, including fuel cells and metal-air batteries. In order to realize their practical applications, highly efficien...Efficient oxygen electrocatalysts are the key elements of numerous energy storage and conversion devices, including fuel cells and metal-air batteries. In order to realize their practical applications, highly efficient and inexpensive non-noble metal-based oxygen electrocatalysts are urgently required. Herein, we report a novel iron-chelated urea-formaldehyde resin hydrogel for the synthesis of Fe-N-C electrocatalysts. This novel hydrogel is prepared using a new instantaneous （20 s） one-step scalable strategy, which theoretically ensures the atomic-level dispersion of Fe ions in the urea-formaldehyde resin, guaranteeing the microstructural homogeneity of the electrocatalyst. Consequentl~ the prepared electrocatalyst exhibits higher catalytic activity and durability in the oxygen reduction （ORR） and evolution （OER） reactions than the commercial Pt/C catalyst. Furthermore, the above catalyst also shows a much better performance in rechargeable Zn-air batteries, including higher power density and better cycling stability. The developed synthetic approach opens up new avenues toward the development of sustainable active electrocatalysts for electrochemical energy devices.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22102167 and U21A20317).
文摘It is highly desirable to design efficient and stable hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)electrocatalysts for the development of renewable energy technologies.Herein,density functional theory(DFT)calculations were conducted to systematically investigate a series of TMN_(x)O_(4-x)-HTT(TM=Fe,Co,Ni,Ru,Rh,Pd,Ir and Pt;HTT=hexahydroxy tetraazanaphthotetraphene)analogs of two-dimensional(2D)conductive metal-organic frameworks(MOFs)as potential electrocatalysts for the HER,OER and ORR.The thermodynamic and electrochemical stability simulations suggest that these designed catalysts are stable.Remarkably,CoO_(4)-HTT,RhN_(3)O_(1)-HTT and IrN3O1-HTT are predicted to be the most promising catalysts for the HER,OER and ORR,respectively,surpassing the catalytic activity of corresponding benchmark catalysts.The volcano plots were established based on the scaling relationship of adsorption Gibbs free energy of intermediates.The results reveal that regulating combinations of metal active centers and local coordination environments could effectively balance the interaction strength between intermediates and catalysts,thus achieving optimal catalytic activity.Our findings not only opt for the promising HER/OER/ORR electrocatalysts but also guide the design of efficient electrocatalysts based on 2D MOFs materials.
文摘制备具有氧还原(ORR)与氧释放(OER)双功能催化活性的特殊孔道结构电催化剂是锂氧电池研究的挑战之一。本文以氧化石墨烯、硝酸铁、硝酸镧、柠檬酸为原料,结合溶胶凝胶和水热合成方法,制备出还原氧化石墨烯(RGO)与铁酸镧(LaFeO_3)复合的双功能催化剂(RGO-LaFeO_3)。X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱和Raman光谱分析结果确认该复合催化剂由纯相钙钛矿结构LaFeO_3和还原氧化石墨烯组成,扫描电子显微镜(SEM)观察到LaFeO_3纳米颗粒均匀地负载在RGO片层表面。锂氧电池测试结果指出,相对于LaFeO_3纳米粒子(NP-LaFeO_3),RGO-LaFeO_3催化剂具有更好的ORR和OER催化活性,归因于RGO特殊的三维导电多孔结构与LaFeO_3纳米粒子的协同催化作用。以RGO-LaFeO_3作为阴极催化剂的锂氧电池在限1000 m Ah?g^(-1)比容量、100 m A?g^(-1)电流密度条件下,可实现36周稳定的充放电循环,展示出良好的应用前景。
文摘The pyrolysis under inert atmosphere has been widely used for the synthesis of metal containing heteroatoms doped carbon materials, versatile catalysts for various reactions. However, it is difficult to prevent metal nanoparticles aggregation during pyrolysis process. Herein, we reported the efficient synthesis of nitrogen doped carbon hollow nanospheres with cobalt nanoparticles （Co NP, ca. 10nm in size） distributed uniformly in the shell via pyrolysis of yolk-shell structured Zn-Co-ZIFs@polydopamine （PDA）. PDA acted as both protection layer and carbon source, which successfully prevented the aggregation of cobalt nanoparticles during high-temperature pyrolysis process. The Co NP and N containing carbon （Co NP/NC） hollow nanospheres were active for both oxygen evolution reaction （OER） and oxygen reduction reaction （ORR）, affording overpotential of 430 mV at 10 mA/cm2 for OER in 1 M KOH and comparable half-wave potential to that of Pt/C （0.80V vs RHE） for ORR in 0.1 M KOH. The superior performance of carbon hollow nanospheres for both OER and ORR was mainly attributed to its small metal nanoparticles, N-doping and hollow nanostructure. The protection and confinement effect that originated from PDA coating strategy could be extended to the synthesis of other hollow structured carbon materials, especially the ones with small metal nanoparticles.
文摘Co-doped perovskite oxide La_(0.4)Sr_(0.6)Co_xMn_(1-x)O_3(x=0, 0.2, 0.4) composites are prepared by sol-gel method utilizing citric acid as chelating agent. These composites show good catalytic activities when tested as catalysts rechargeable lithium-air batteries. In particular, the La_(0.4)Sr_(0.6)Co_(0.4)Mn_(0.6)O_3 shows a lower potential gap. When these samples are tested as catalysts for Li-air batteries at a current density of100 mA g^(-1), the discharge capacities with different La_(0.4)Sr_(0.6)Co_xMn_(1-x)O_3(x=0,0.2, 0.4) catalysts are 5819, 6420, and 7227 mA h g^(-1),respectively. In addition, under a capacity limitation of 1000 mA h g^(-1), the cell using La_(0.4)Sr_(0.6)Co_(0.4)Mn_(0.6)O_3 as catalyst shows good cycling stability up to 46 cycles. The good electrochemical performance suggests that suitable doping of Co in Mn site of La_(0.4)Sr_(0.6)MnO_3 could be a promising route to improve the catalytic activity.
基金Fundamental Research Funds for the Central UniversitiesChinese Academy of SciencesNational Natural Science Foundation of China,Grant/Award Numbers:12375301,21503227。
文摘Electrocatalysis,which involves oxidation and reduction reactions with direct electron transfer,is essential for a variety of clean energy conversion devices.Currently,the vast majority of studies regarding electrocatalysis reactions focus on strong acidic or alkaline media because of the higher catalytic activity.Nevertheless,some inherent drawbacks,including the corrosive environment,expensive proton exchange membranes,and side effects,are still hard to break through.A sustainably promising way to overcome these shortcomings is to deploy neutral/near-neutral electrolytes for electrocatalysis reactions.Unfortunately,insufficient research in this area due to the lack of attention to related issues has slowed down the development process.In this review,we systematically review the catalytic reaction mechanisms,neutral electrolytes,electrocatalysts,and modification strategies carried out in neutral media on the three most common electrocatalytic reactions,that is,hydrogen evolution reaction,oxygen reduction reaction,and oxygen evolution reaction.Furthermore,the advanced characterization tools for guiding catalyst synthesis and mechanistic studies are also summarized.Eventually,we propose some challenges and perspectives on electrocatalysis reactions in neutral media and hope it will attract more research interest and provide guidance in neutral electrocatalysis.
基金supported by the Australian Research Council (ARC) through the ARC Future Fellow project (FT110100800)Discovery Project (DP160104340)+3 种基金DECRA project (DE140100619)the support from the University of Technology Sydney Chancellor’s Post Doctoral Fellowshipthe financial support from Shanghai Science & Technology Committee (15520720600)the support from Program for Professor of Special Appointment in Shanghai (Eastern Scholar)
文摘Lithium oxygen battery has the highest theoretical capacity among the rechargeable batteries and it can reform energy storage technology if it comes to commercialization. However,many critical challenges,mainly embody as low charge/discharge round-trip efficiency and poor cycling stability,impede the development of Li-O_2 batteries. The electrolyte decomposition,lithium metal anode corrosion and sluggish oxygen reaction kinetics at cathode are all responsible for poor electrochemical performances.Particularly,the catalytic cathode of Li-O_2 batteries,playing a crucial role to reduce the oxygen during discharging and to decompose discharge products during charging,is regarded as a breakthrough point that has been comprehensive investigated. In this review,the progress and issues of electrolyte,anode and cathode,especially the catalysts used at cathode,are systematically summarized and discussed.Then the perspectives toward the developments of a long life Li-O_2 battery are also presented at last.
文摘Efficient oxygen electrocatalysts are the key elements of numerous energy storage and conversion devices, including fuel cells and metal-air batteries. In order to realize their practical applications, highly efficient and inexpensive non-noble metal-based oxygen electrocatalysts are urgently required. Herein, we report a novel iron-chelated urea-formaldehyde resin hydrogel for the synthesis of Fe-N-C electrocatalysts. This novel hydrogel is prepared using a new instantaneous （20 s） one-step scalable strategy, which theoretically ensures the atomic-level dispersion of Fe ions in the urea-formaldehyde resin, guaranteeing the microstructural homogeneity of the electrocatalyst. Consequentl~ the prepared electrocatalyst exhibits higher catalytic activity and durability in the oxygen reduction （ORR） and evolution （OER） reactions than the commercial Pt/C catalyst. Furthermore, the above catalyst also shows a much better performance in rechargeable Zn-air batteries, including higher power density and better cycling stability. The developed synthetic approach opens up new avenues toward the development of sustainable active electrocatalysts for electrochemical energy devices.
