N-Doped Carbon-Supported CoCu-Layered Double Hydroxide Nanosheets as Antibacterial Oxygen Reduction Catalysts for Microbial Fuel Cells
Liang Li, Demin Jiang, Sainan Cai, Shikuo Li, Yuqiao Wang
Abstract
The sluggish reaction kinetics of the oxygen reduction reaction (ORR) and the formation of a biofilm on the cathode prevent efficient and stable operation of microbial fuel cells (MFCs). In this work, zeolitic imidazolate framework-derived N-doped carbon-supported CoCu-layered double hydroxide nanosheets (CoCu-LDH@NC) were synthesized as a bifunctional cathode catalyst for MFCs. CoCu-LDH supported on CoO@NC induced the production of carbon nanotubes (CNTs) from the NC matrix. CNTs and CoCu-LDH nanosheets improved the atomic reaction efficiency and active area for the ORR. The high-speed electron-transfer channel was attributed to two-dimensional CoCu-LDH nanosheets and one-dimensional CNTs. The catalytic activity and stability of CoO@NC were sustained through the incorporation of CoCu-LDH nanosheets. The electronic interaction of CoCu-LDH and CoO@NC enhanced the ORR catalytic activities. CoCu-LDH nanosheets generated reactive oxygen species (ROS) and Cu +, improving the antibacterial activity to prevent the growth of biofilm for MFCs. CoCu-LDH@NC demonstrated superior oxygen reduction activity with a half-wave potential of 0.84 V and an onset potential of 0.89 V. The maximum power density and operating cycle of the MFCs assembled with CoCu-LDH@NC reached 1012 mW m –2 and 170 h, respectively. This work offers guidance to enhancing the ORR catalytic activity and stability by designing antibacterial ORR catalysts.