Nanoflower-branch LDHs and CoNi alloy derived from electrospun carbon nanofibers for efficient oxygen electrocatalysis in microbial fuel cells

Abstract

Designing rational nanostructure to promote the oxygen reduction reaction (ORR) catalytic activity of microbial fuel cells (MFCs) is desirable but still remains a huge challenge. In this work, an elaborately designed strategy is proposed to deposit layered double hydroxides (LDHs) on the surface of ZIF-67 grown along nanofibers, thereby obtaining nanoflower-branch composites (CoNi-LDH@CNFs) with a rich cavity structure supported by electrospinning nanofibers. During the pyrolysis process, the variable cobalt in ZIFs is captured by LDHs nanosheets to generate CoNi alloy. As expected, CoNi-LDH@CNFs exhibits brilliant ORR catalytic activity. The as-prepared catalyst is an outstanding cathode in MFC, with a maximum power density of 1390.37 mW/m2, superior to Pt/C corresponding MFC (843.67 mW/m2). Impressively, the nanofiber-derived catalyst exhibits long-term durability in single-chamber MFCs. This work provides a new perspective for the combination of LDHs and nanofiber-derived materials, and gives promising performance in realistic MFCs applications.