Three-dimensional ZIF-67 attached lamellar Ti3AlC2 combined with ZnAl-LDH as cathode catalyst for enhancing oxygen reduction reaction of microbial fuel cells

Abstract

In this study, a simple hydrothermal method was used to prepare the cathode catalyst of microbial fuel cells (MFCs). The three-dimensional structure of ZIF-67 attached to the lamellar Ti3AlC2/ZnAl-layered double hydroxide (LDH) was observed. (010), (012), (015) were the obvious peaks of the composite ZIF-67@Ti3AlC2/ZnAl-LDH. Ti, N, C, Al, O, F were relatively uniformly distributed on the surface of the composite material. The maximum voltage of ZIF-67@Ti3AlC2/ZnAl-LDH-MFC was 576 mV and the stabilization time was 8 d. The maximum power density of ZIF-67@Ti3AlC2/ZnAl-LDH-MFC was 587 mW/m2, which was 1.32 times of Ti3AlC2/ZnAl-LDH-MFC (446 mW/m2) and 2.69 times of Ti3AlC2-MFC (218 mW/m2). Ti3AlC2 with large interlayer spacing and high specific surface area were perfectly composited with multi-layer nanosheets of ZnAl-LDH, and ZIF-67 attached to the surface enhanced the reaction center and activity of the composite material, which promoted oxygen reduction reaction and improved MFC performances.