Functional Ni/MnO2 heterostructure electrocatalysts based on self-sacrifice-induced LDHs anchored on nanofibers for microbial fuel cells

Abstract

Designing cost-effective, highly active oxygen reduction catalysts for high-power-density microbial fuel cells (MFCs) is a significant challenge. To address this, this study uniformly dispersed layered double hydroxides (LDHs) on nanofiber surfaces, and subsequently utilized the self-sacrifice method of zeolite imidazole frameworks (ZIFs) to synthesize LDH/ZIF@CNFs bimetallic heterostructure with precise lattice matching. Experimental results collectively verified that LDH/ZIF@CNFs-12 exhibits an onset potential of -0.087 V, surpassing Pt/C (-0.098 V). Impressively, MFC equipped with LDH/ZIF@CNFs-12 achieves a high power density of 939.05 mW/cm2, surpassing Pt/C (859.74 mW/cm2). The excellent electrocatalytic performance of this catalyst originates from the rich active sites exposed in the LDHs core during the MOFs-assisted synthesis process, and the synergistic catalysis achieved by the formation of heterojunctions. In addition, 3D nanofibers uniformly disperse active sites and reduce large band gaps. This work unveils a new perspective for cost-effective, eco-friendly, and sustainable catalysts suitable for MFCs.