Noble metal-free and highly efficient electrocatalytic materials with hierarchically porous structures continue to be studied for the oxygen reduction reaction(ORR) in microbial fuel cells(MFCs). We report bimetal-org...Noble metal-free and highly efficient electrocatalytic materials with hierarchically porous structures continue to be studied for the oxygen reduction reaction(ORR) in microbial fuel cells(MFCs). We report bimetal-organic framework(bi-MOF)-derived nanocubic Swiss cheese-like carbons with a novel three-dimensional hierarchically porous structure(3D Co-N-C) prepared by utilizing cetyltrimethylammonium bromide(CTAB) as a structure-directing agent to control the formation of a nanocubic skeleton, and silica spheres as a template to form a mesoporous structure. The elemental composition and chemical morphology of this material can be tuned through the Zn/Co ratio to optimize its ORR catalytic activity. The optimized 3D Co-N-C displays excellent ORR catalytic performance(half-wave potential as high as 0.754 V vs. reversible hydrogen electrode and diffusion-limiting current density of 5.576 mA cm^(-2)) in 0.01 mol L^(-1) phosphate-buffered saline(PBS electrolyte),showing it can compete with the commercial 20 wt% Pt/C catalysts. The catalytic capability and long-term durability of 3D Co-N-C as an air-filled cathode electrocatalyst in an MFC device are tested, showing that the 3D CoNC-MFC can reach a high power density of 1257 mW m^(-2) and provide a competitive voltage during a periodic feeding operation for 192 h;these values are much higher than those of the Pt/C-MFC.展开更多
基金supported by the National Natural Science Foundation of China (51976143)the National Key Research and Development Program of China (2018YFA0702001)Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (XHD2020-002)。
文摘Noble metal-free and highly efficient electrocatalytic materials with hierarchically porous structures continue to be studied for the oxygen reduction reaction(ORR) in microbial fuel cells(MFCs). We report bimetal-organic framework(bi-MOF)-derived nanocubic Swiss cheese-like carbons with a novel three-dimensional hierarchically porous structure(3D Co-N-C) prepared by utilizing cetyltrimethylammonium bromide(CTAB) as a structure-directing agent to control the formation of a nanocubic skeleton, and silica spheres as a template to form a mesoporous structure. The elemental composition and chemical morphology of this material can be tuned through the Zn/Co ratio to optimize its ORR catalytic activity. The optimized 3D Co-N-C displays excellent ORR catalytic performance(half-wave potential as high as 0.754 V vs. reversible hydrogen electrode and diffusion-limiting current density of 5.576 mA cm^(-2)) in 0.01 mol L^(-1) phosphate-buffered saline(PBS electrolyte),showing it can compete with the commercial 20 wt% Pt/C catalysts. The catalytic capability and long-term durability of 3D Co-N-C as an air-filled cathode electrocatalyst in an MFC device are tested, showing that the 3D CoNC-MFC can reach a high power density of 1257 mW m^(-2) and provide a competitive voltage during a periodic feeding operation for 192 h;these values are much higher than those of the Pt/C-MFC.
