Developing non-expensive, highly active and highly stable electrocatalysts for hydrogen evolution has aroused extensive attention, owing to the necessity of novel clean and sustainable energy carriers. In this paper, ...Developing non-expensive, highly active and highly stable electrocatalysts for hydrogen evolution has aroused extensive attention, owing to the necessity of novel clean and sustainable energy carriers. In this paper, we report a synthesis of free-standing three-dimensional hierarchical MoS_2/CoS_2 heterostructure arrays through a convenient process. The investigation of electrocatalytic HER performance suggests that the MoS_2/CoS_2 hybrid catalyst exhibits significant enhancement in HER(onsetpotential and potential at a current density of 100 mA cm^(-2) are 20 mV and125 mV, respectively) and superior durability(no shift of current density is observed after a continuous scanning of 3000 times) compared with individual CoS_2 and MoS_2. The superior HER performance was attributed to the formation of the interface between CoS_2 and MoS_2 through the electrochemical characterization, Raman, XPS analysis, and the control experiment. The lower onsetpotential, higher current density, excellent durability, and the free-standing structure of the three-dimensional hierarchical MoS_2/CoS_2 heterostructure array make it a promising cathode catalyst suitable for widespread application.展开更多
Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as se...Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as self-sacrificial templates to synthesize yolk-shell structured CoNi-G SSs@ZIF-67 nanospheres.The derived NiCo2S4@CoS2/MoS2 double-shelled hollow nanospheres integrate the adsorbate evolution mechanism(AEM)and lattice oxygen mechanism(LOM),enabling synergistic dual catalytic pathways.Nickel modulation facilitates active species reconstruction in NiCo_(2)S_(4),enhancing lattice oxygen activity and optimizing the LOM pathway.Characterization results indicate that anode activation triggered the redox processes of metal and lattice oxygen sites,involving the formation and re-filling of oxygen vacancies.Additionally,the CoS_(2)/MoS_(2) heterostructure enhances the AEM pathway,as supported by density functional theory calculations,which demonstrate optimized adsorption of intermediates for both hydrogen evolution reaction and OER.The assembled anion exchange membrane water splitting device can deliver a catalytic current of 500 mA cm^(-2) at 1.74 V under commercial catalytic operating conditions(1 mol L^(-1) KOH)for 150 h,with negligible degradation.This work provides important insights into the understanding of OER mechanisms and the design of high-performance water-splitting electrocatalysts,while also opening new avenues for developing multifunctional materials with multi-shell structures.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.:51503062, 51402100, 21573063 and 21573066)the Youth 1000 Talent Program of China+1 种基金the Fundamental Research Funds for the Central UniversitiesInter-discipline Research Program of Hunan University
文摘Developing non-expensive, highly active and highly stable electrocatalysts for hydrogen evolution has aroused extensive attention, owing to the necessity of novel clean and sustainable energy carriers. In this paper, we report a synthesis of free-standing three-dimensional hierarchical MoS_2/CoS_2 heterostructure arrays through a convenient process. The investigation of electrocatalytic HER performance suggests that the MoS_2/CoS_2 hybrid catalyst exhibits significant enhancement in HER(onsetpotential and potential at a current density of 100 mA cm^(-2) are 20 mV and125 mV, respectively) and superior durability(no shift of current density is observed after a continuous scanning of 3000 times) compared with individual CoS_2 and MoS_2. The superior HER performance was attributed to the formation of the interface between CoS_2 and MoS_2 through the electrochemical characterization, Raman, XPS analysis, and the control experiment. The lower onsetpotential, higher current density, excellent durability, and the free-standing structure of the three-dimensional hierarchical MoS_2/CoS_2 heterostructure array make it a promising cathode catalyst suitable for widespread application.
文摘Activating both metal and lattice oxygen sites for efficient oxygen evolution reactions(OER)is a critical challenge.This study pioneers a novel approach,employing cobalt-nickel glycerate solid spheres(CoNi-G SSs)as self-sacrificial templates to synthesize yolk-shell structured CoNi-G SSs@ZIF-67 nanospheres.The derived NiCo2S4@CoS2/MoS2 double-shelled hollow nanospheres integrate the adsorbate evolution mechanism(AEM)and lattice oxygen mechanism(LOM),enabling synergistic dual catalytic pathways.Nickel modulation facilitates active species reconstruction in NiCo_(2)S_(4),enhancing lattice oxygen activity and optimizing the LOM pathway.Characterization results indicate that anode activation triggered the redox processes of metal and lattice oxygen sites,involving the formation and re-filling of oxygen vacancies.Additionally,the CoS_(2)/MoS_(2) heterostructure enhances the AEM pathway,as supported by density functional theory calculations,which demonstrate optimized adsorption of intermediates for both hydrogen evolution reaction and OER.The assembled anion exchange membrane water splitting device can deliver a catalytic current of 500 mA cm^(-2) at 1.74 V under commercial catalytic operating conditions(1 mol L^(-1) KOH)for 150 h,with negligible degradation.This work provides important insights into the understanding of OER mechanisms and the design of high-performance water-splitting electrocatalysts,while also opening new avenues for developing multifunctional materials with multi-shell structures.
