Cobalt oxides nanoparticles supported on nitrogen-doped carbon nanotubes as high-efficiency cathode catalysts for microbial fuel cells

By Yang, Wei; Lu, Jia En; Zhang, Yudong; Peng, Yi; Mercado, Rene; Li, Jun; Zhu, Xun; Chen, Shaowei
Published in Inorganic Chemistry Communications 2019

Abstract

Microbial fuel cell is a unique energy technology where both wastewater treatment and electricity generation take place concurrently. However, the performance is typically rather limited due to the sluggish electron-transfer kinetics of oxygen reduction reaction at the cathode. Thus, development of high-performance cathode catalysts is of fundamental significance for the wide-spread application of microbial fuel cell. In this study, nanocomposites based on cobalt oxide nanoparticles supported on nitrogen-doped carbon nanotubes (Co/N-CNT) were synthesized by controlled pyrolysis of graphitic carbon nitride and cobalt acetate. Electrochemical tests indicated that the Co/N-CNT nanocomposites exhibited a high ORR electrocatalytic activity with a half-wave potential of +0.82 V and onset potential of +0.91 V vs. RHE, mostly via a four-electron reduction pathway. This was ascribed to the formation of high-efficiency CoN active sites that facilitated the ORR kinetics. A microbial fuel cell using the as-prepared Co/N-CNT as the cathode catalyst achieved a maximum power density of 1260 mW m?2, which was 16.6% higher than that based on state-of-art Pt/C catalyst (1080 mW m?2). The results suggest that Co/N-CNT nanocomposites may serve as viable cathode catalysts in microbial fuel cell application.

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