Constructing Co3ZnC/Co Mott-Schottky heterojunction to enhance dual active sites of catalyst as an ORR catalyst for Microbial fuel cells

In the field of oxygen electrocatalysis, interface engineering was regarded as a pivotal technique for developing cost-effective catalysts with well-defined structures and enhanced stability. Here, varying ratios of ZIF-8/67 were employed to synthesize an N-doped C-coated Co3ZnC/Co heterojunction structure (Co3ZnC/Co@NC). The formation of heterojunctions facilitated the transfer of charge from Co nanoparticles to Co3ZnC, altering the surface structure to accelerate the cleavage of the O-O bond in the *OOH intermediate. The optimized Co3ZnC/Co@NC catalyst exhibited a half-wave potential (E1/2) of 0.763 V in PBS electrolyte, which was 77 mV more positive than that of commercial Pt/C (0.686 V). Meanwhile, Co3ZnC/Co@NC displayed excellent methanol tolerance (86.27%) and operational stability, with a mere 3 mV reduction after 5000 cyclic voltammetry (CV) cycles. It was noteworthy that the material exhibits high performance as an air cathode in microbial fuel cells (MFCs), displaying high power density (1.28 W m-2) and outstanding stability (60 days). This work presented novel insights into the preparation of durable ORR catalysts for AC-MFC applications.