Cathode catalyst selection for enhancing oxygen reduction reactions of microbial fuel cells: COF-300@NiAl-LDH/GO and Ti3AlC2/NiCoAl-LDH

In this study, a cathode catalyst for microbial fuel cells (MFCs) was successfully prepared by a simple step-by-step hydrothermal method. Graphene oxide (GO) and layered double hydroxide (LDH) composite substrate and three-dimensional covalent organic framework materials (COF-300) grown vertically on the surface were observed. (003), (006), (012), (018), (110) were the obvious crystal plane of the composite [email protected]/GO. C, O, N, Ni, Na, Al and other elements existed on the surface of the composite. The maximum power density produced by [email protected]/GO-MFC was 481.69 mW/m2, which was 1.22 times of Ti3AlC2/NiCoAl-LDH-MFC (393.82 mW/m2) and 2.21 times of Ti3AlC2-MFC (217.73 mW/m2). The maximum voltage of [email protected]/GO-MFC was 518 mV and it could remain stable within 8 days. GO was used as the substrate to improve the conductivity; LDH was used to enhance the catalytic activity and electron transfer rate; The three-dimensional bulk COF-300 attached to the surface enhanced the surface area and catalytic properties; The above jointly promoted oxygen reduction reaction of cathode, so as to improve MFC performances.