Herein, Co_3O_4 nanoparticles/nitrogen-doped carbon(Co_3O_4/NPC) composites with different structures were prepared via a facile method. Structure control was achieved by the rational morphology design of ZIF-67 precu...Herein, Co_3O_4 nanoparticles/nitrogen-doped carbon(Co_3O_4/NPC) composites with different structures were prepared via a facile method. Structure control was achieved by the rational morphology design of ZIF-67 precursors, which were then pyrolyzed in air to obtain Co_3O_4/NPC composites. When applied as catalysts for the oxygen evolution reaction(OER), the M-Co_3O_4/NPC composites derived from the flower-like ZIF-67 showedsuperior catalytic activities than those derived from the rhombic dodecahedron and hollow spherical ZIF-67. The former M-Co_3O_4/NPC composite displayed a small overpotential of 0.3 V, low onset potential of 1.41 V, small Tafel slope of 83 m V dec^(-1), and a desirable stability.(94.7% OER activity was retained after 10 h.) The excellent performance of the flower-like M-Co_3O_4/NPC composite in the OER was attributed to its favorable structure.展开更多
Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the ...Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the most conventional and classical non-noble metal-based electrocatalysts for OER,while TM basic salts[M^(2+)(OH)_(2-x)(A_(m^(-))_(x/m),A=CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)]consisting of OH−and another anion have drawn extensive research interest due to its higher catalytic activity in the past decade.In this review,we summarize the recent advances of TM basic salts and their application in OER and further overall water splitting.We categorize TM basic salt-based OER pre-catalysts into four types(CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)according to the anion,which is a key factor for their outstanding performance towards OER.We highlight experimental and theoretical methods for understanding the structure evolution during OER and the effect of anion on catalytic performance.To develop bifunctional TM basic salts as catalyst for the practical electrolysis application,we also review the present strategies for enhancing its hydrogen evolution reaction activity and thereby improving its overall water splitting performance.Finally,we conclude this review with a summary and perspective about the remaining challenges and future opportunities of TM basic salts as catalysts for water electrolysis.展开更多
OER catalyst of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C(NiFeSC series)mixed crystal composite nanofibers was prepared by electrospinning and atmospheric heat treatment process.The testing results indicate that the diameters of Ni_(...OER catalyst of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C(NiFeSC series)mixed crystal composite nanofibers was prepared by electrospinning and atmospheric heat treatment process.The testing results indicate that the diameters of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C composite nanofibers is about 200 nm,the grains size is about 1-3 nm,and the fiber surface is rough.The electrochemical test results show that the heterojunction of the prepared Ni_(3)Fe/Ni_(4)S_(3)/Ni/C hybrid crystal composite nanofiber has synergistic effect with sulfide,and exhibits good electrocatalytic activity of water decomposition and OER in alkaline system.The OER electrocatalytic performance of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C composite electrode prepared via a heat treatment at 1000℃process was tested in 1 mol/L KOH electrolytes.The results show that the overpotential is about 298 mV,the Tafel slope is about 74 mV?dec-1,and the surface resistance is about 1.69Ω·cm^(2),at the current density of 10 mA·cm^(-2).展开更多
Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution...Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution reaction(OER)is a critical step in water electrolysis and is often limited by its slow kinetics.Two main mechanisms,namely the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM),are commonly considered in the context of OER.However,designing efficient catalysts based on either the AEM or the LOM remains a topic of debate,and there is no consensus on whether activity and stability are directly related to a certain mechanism.Considering the above,we discuss the characteristics,advantages,and disadvantages of AEM and LOM.Additionally,we provide insights on leveraging the LOM to develop highly active and stable OER catalysts in future.For instance,it is essential to accurately differentiate between reversible and irreversible lattice oxygen redox reactions to elucidate the LOM.Furthermore,we discuss strategies for effectively activating lattice oxygen to achieve controllable steady-state exchange between lattice oxygen and an electrolyte(OH^(-)or H_(2)O).Additionally,we discuss the use of in situ characterization techniques and theoretical calculations as promising avenues for further elucidating the LOM.展开更多
The oxygen evolution reaction (OER) dominates the efficiency of electrocatalytic water splitting owing to its sluggish kinetics.Perovskite oxides (ABO_(3)) have emerged as promising candidates to accelerate the OER pr...The oxygen evolution reaction (OER) dominates the efficiency of electrocatalytic water splitting owing to its sluggish kinetics.Perovskite oxides (ABO_(3)) have emerged as promising candidates to accelerate the OER process owing to their high intrinsic activities and tailorable properties.Fe ions in perovskite oxides have been proved to be a highly catalytic element for OER,while some Fe-based perovskites such as SrTi_(0.8)Fe_(0.2)O_(3-δ)(STF) and La_(0.66)Ti_(0.8)Fe_(0.2)O_(3-δ)(LTF) exhibit inferior OER activity.Yet the essential reason is still unclear and the effective method to promote the activity of such perovskite is also lacking.Herein,an in-situ exsolution strategy was proposed to boost the OER by migrating Fe from the bulk to the surface.Significantly enhanced OER activity was achieved on STF and LTF perovskites with surfacedecorated oxygen vacancies and Fe nanoparticles.In addition,theoretical calculation confirmed that the oxygen vacancies and Fe nanoparticle on surface could lower the overpotential of OER by facilitating the adsorption of OH^(-).From this study,migration of the active elements in perovskite is found to be an effective strategy to increase the quantity and activity of active sites,providing new insights and understanding for designing efficient OER catalysts.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. 10 nm 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 m V at 10 m A/cm^2 for OER in 1 M KOH and comparable half-wave potential to that of Pt/C(0.80 V 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
基金supported by the Scientific and Technological Innovation Platform of Fujian Province(2006L2003)Scientific Research Project of Wuyi University(YJ201706)
文摘Herein, Co_3O_4 nanoparticles/nitrogen-doped carbon(Co_3O_4/NPC) composites with different structures were prepared via a facile method. Structure control was achieved by the rational morphology design of ZIF-67 precursors, which were then pyrolyzed in air to obtain Co_3O_4/NPC composites. When applied as catalysts for the oxygen evolution reaction(OER), the M-Co_3O_4/NPC composites derived from the flower-like ZIF-67 showedsuperior catalytic activities than those derived from the rhombic dodecahedron and hollow spherical ZIF-67. The former M-Co_3O_4/NPC composite displayed a small overpotential of 0.3 V, low onset potential of 1.41 V, small Tafel slope of 83 m V dec^(-1), and a desirable stability.(94.7% OER activity was retained after 10 h.) The excellent performance of the flower-like M-Co_3O_4/NPC composite in the OER was attributed to its favorable structure.
基金supported by the financial support from Natural Science Foundation of China(Nos.21871065,22209129 and 22071038)High-Level Innovation and Entrepreneurship(QCYRCXM-2022-123)+1 种基金support from the“Young Talent Support Plan”of Xi’an Jiaotong University(HG6J024)“Young Talent Lift Plan”of Xi’an city(095920221352).
文摘Electrocatalytic oxygen evolution reaction(OER)has been recognized as the bottleneck of overall water splitting,which is a promising approach for sustainable production of H_(2).Transition metal(TM)hydroxides are the most conventional and classical non-noble metal-based electrocatalysts for OER,while TM basic salts[M^(2+)(OH)_(2-x)(A_(m^(-))_(x/m),A=CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)]consisting of OH−and another anion have drawn extensive research interest due to its higher catalytic activity in the past decade.In this review,we summarize the recent advances of TM basic salts and their application in OER and further overall water splitting.We categorize TM basic salt-based OER pre-catalysts into four types(CO_(3)^(2−),NO_(3)^(−),F^(−),Cl^(−)according to the anion,which is a key factor for their outstanding performance towards OER.We highlight experimental and theoretical methods for understanding the structure evolution during OER and the effect of anion on catalytic performance.To develop bifunctional TM basic salts as catalyst for the practical electrolysis application,we also review the present strategies for enhancing its hydrogen evolution reaction activity and thereby improving its overall water splitting performance.Finally,we conclude this review with a summary and perspective about the remaining challenges and future opportunities of TM basic salts as catalysts for water electrolysis.
基金Funded by the Doctoral Fund of Chengdu University (2081919131)the Open Fund of Material Corrosion and Protection Key Laboratory of Sichuan Province (2021CL27)the Sichuan Science and Technology Program (2023YFG0229)。
文摘OER catalyst of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C(NiFeSC series)mixed crystal composite nanofibers was prepared by electrospinning and atmospheric heat treatment process.The testing results indicate that the diameters of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C composite nanofibers is about 200 nm,the grains size is about 1-3 nm,and the fiber surface is rough.The electrochemical test results show that the heterojunction of the prepared Ni_(3)Fe/Ni_(4)S_(3)/Ni/C hybrid crystal composite nanofiber has synergistic effect with sulfide,and exhibits good electrocatalytic activity of water decomposition and OER in alkaline system.The OER electrocatalytic performance of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C composite electrode prepared via a heat treatment at 1000℃process was tested in 1 mol/L KOH electrolytes.The results show that the overpotential is about 298 mV,the Tafel slope is about 74 mV?dec-1,and the surface resistance is about 1.69Ω·cm^(2),at the current density of 10 mA·cm^(-2).
基金the support from the National Key R&D Program of China(2020YFA0710000)the National Natural Science Foundation of China(Nos.22008170,22278307,22222808,21978200)+1 种基金the Haihe Laboratory of Sustainable Chemical Transformationsthe Tianjin Research Innovation Project for Postgraduate Students(2022B KYZ035)。
文摘Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution reaction(OER)is a critical step in water electrolysis and is often limited by its slow kinetics.Two main mechanisms,namely the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM),are commonly considered in the context of OER.However,designing efficient catalysts based on either the AEM or the LOM remains a topic of debate,and there is no consensus on whether activity and stability are directly related to a certain mechanism.Considering the above,we discuss the characteristics,advantages,and disadvantages of AEM and LOM.Additionally,we provide insights on leveraging the LOM to develop highly active and stable OER catalysts in future.For instance,it is essential to accurately differentiate between reversible and irreversible lattice oxygen redox reactions to elucidate the LOM.Furthermore,we discuss strategies for effectively activating lattice oxygen to achieve controllable steady-state exchange between lattice oxygen and an electrolyte(OH^(-)or H_(2)O).Additionally,we discuss the use of in situ characterization techniques and theoretical calculations as promising avenues for further elucidating the LOM.
基金financial supports from the Youth Innovation Fund of Dalian Institute of Chemical Physics (DICP I202126)the Strategic Priority Research Program of Chinese Academy of Sciences (XDB17020400)。
文摘The oxygen evolution reaction (OER) dominates the efficiency of electrocatalytic water splitting owing to its sluggish kinetics.Perovskite oxides (ABO_(3)) have emerged as promising candidates to accelerate the OER process owing to their high intrinsic activities and tailorable properties.Fe ions in perovskite oxides have been proved to be a highly catalytic element for OER,while some Fe-based perovskites such as SrTi_(0.8)Fe_(0.2)O_(3-δ)(STF) and La_(0.66)Ti_(0.8)Fe_(0.2)O_(3-δ)(LTF) exhibit inferior OER activity.Yet the essential reason is still unclear and the effective method to promote the activity of such perovskite is also lacking.Herein,an in-situ exsolution strategy was proposed to boost the OER by migrating Fe from the bulk to the surface.Significantly enhanced OER activity was achieved on STF and LTF perovskites with surfacedecorated oxygen vacancies and Fe nanoparticles.In addition,theoretical calculation confirmed that the oxygen vacancies and Fe nanoparticle on surface could lower the overpotential of OER by facilitating the adsorption of OH^(-).From this study,migration of the active elements in perovskite is found to be an effective strategy to increase the quantity and activity of active sites,providing new insights and understanding for designing efficient OER catalysts.
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. 10 nm 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 m V at 10 m A/cm^2 for OER in 1 M KOH and comparable half-wave potential to that of Pt/C(0.80 V 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.
