Yolk–shell urchin-like porous Co_(3)O_(4)/NiO@C microspheres were successfully synthesized via a facile solvothermal method and annealing treatment under an argon atmosphere.High reversible specific capacity,long cyc...Yolk–shell urchin-like porous Co_(3)O_(4)/NiO@C microspheres were successfully synthesized via a facile solvothermal method and annealing treatment under an argon atmosphere.High reversible specific capacity,long cycling stability,and excellent rate capability were achieved for the material due to its specific yolk–shell urchin-like porous structure and coated carbon layers.The pores distributed on the yolk and shell,as well as the gap between the yolk and shell,provide numerous pathways for the penetration of electrolyte,and enhance the reversible specific capacity(the initial discharge specific capacity was as high as 1405.7 mA h g^(-1) at 0.1 C).Meanwhile,the stress and volume expansion could be greatly released and relieved through the pores,and long cycling stability was achieved(a high reversible specific capacity of 502.7 mA h g^(-1) was maintained after 1000 cycles at 5 C).The coated carbon layers greatly enhance the conductivity of the yolk–shell urchin-like porous Co_(3)O_(4)/NiO microspheres,accelerate the transmission of electrons,and improve their rate performance(a reversible specific capacity of 397.5 mA h g^(-1) was achieved when the current density was increased to 10 C).展开更多
Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic pr...Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic properties. In order to simultaneously solve these problems, Pd/Co_(3)O_(4)–N–C multidimensional materials with porous structures is designed as the ORR catalysts. In details, the ZIF-67 with polyhedral structure was firstly synthesized and then annealed at high-temperature to prepare the N-doped Co_(3)O_(4)carbon-based material, which was used to homogeneously confine Pd nanoparticles and obtained the Pd/Co_(3)O_(4)–N–C series catalysts. The formation of Co–N and C–N bond could provide efficient active sites for ORR. Simultaneously, the strong electronic interaction in the interface between the Pd and N-doped Co_(3)O_(4)could disperse and avoid the agglomeration of Pd nanoparticles and ensure the exposure of active sites, which is crucial to lower the energy barrier toward ORR and substantially enhance the ORR kinetics. Hence, the Pd/Co_(3)O_(4)–N–C nanocompounds exhibited excellent ORR catalytic performance, ideal Pd mass activity, and durability in 0.1 mol L-1KOH solution compared with Co_(3)O_(4)–N–C and Pd/C. The scalable synthesis method, relatively low cost, and excellent electrochemical ORR performance indicated that the obtained Pd/Co_(3)O_(4)–N–C electrocatalyst had the potential for application on fuel cells.展开更多
基金supported by the National Natural Science Foundation of China(51725101,11727807,51672050,61790581)the Ministry of Science and Technology of China(973 Project No.2018YFA0209102)the science and technology research project of Jiangxi Provincial Department of Education(GJJ200338).
文摘Yolk–shell urchin-like porous Co_(3)O_(4)/NiO@C microspheres were successfully synthesized via a facile solvothermal method and annealing treatment under an argon atmosphere.High reversible specific capacity,long cycling stability,and excellent rate capability were achieved for the material due to its specific yolk–shell urchin-like porous structure and coated carbon layers.The pores distributed on the yolk and shell,as well as the gap between the yolk and shell,provide numerous pathways for the penetration of electrolyte,and enhance the reversible specific capacity(the initial discharge specific capacity was as high as 1405.7 mA h g^(-1) at 0.1 C).Meanwhile,the stress and volume expansion could be greatly released and relieved through the pores,and long cycling stability was achieved(a high reversible specific capacity of 502.7 mA h g^(-1) was maintained after 1000 cycles at 5 C).The coated carbon layers greatly enhance the conductivity of the yolk–shell urchin-like porous Co_(3)O_(4)/NiO microspheres,accelerate the transmission of electrons,and improve their rate performance(a reversible specific capacity of 397.5 mA h g^(-1) was achieved when the current density was increased to 10 C).
基金funded by National Natural Science Foundation of China (21975129)Natural Science Foundation of Jiangsu Province (BK20190759)+1 种基金Nanjing Forestry UniversityPostgraduate Research & Practice Innovation Program of Jiangsu Province (SJCX21_0337)。
文摘Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic properties. In order to simultaneously solve these problems, Pd/Co_(3)O_(4)–N–C multidimensional materials with porous structures is designed as the ORR catalysts. In details, the ZIF-67 with polyhedral structure was firstly synthesized and then annealed at high-temperature to prepare the N-doped Co_(3)O_(4)carbon-based material, which was used to homogeneously confine Pd nanoparticles and obtained the Pd/Co_(3)O_(4)–N–C series catalysts. The formation of Co–N and C–N bond could provide efficient active sites for ORR. Simultaneously, the strong electronic interaction in the interface between the Pd and N-doped Co_(3)O_(4)could disperse and avoid the agglomeration of Pd nanoparticles and ensure the exposure of active sites, which is crucial to lower the energy barrier toward ORR and substantially enhance the ORR kinetics. Hence, the Pd/Co_(3)O_(4)–N–C nanocompounds exhibited excellent ORR catalytic performance, ideal Pd mass activity, and durability in 0.1 mol L-1KOH solution compared with Co_(3)O_(4)–N–C and Pd/C. The scalable synthesis method, relatively low cost, and excellent electrochemical ORR performance indicated that the obtained Pd/Co_(3)O_(4)–N–C electrocatalyst had the potential for application on fuel cells.
