A one-step hydrothermal method for novel Cu–Co bimetallic sulfides to improve the power performance of microbial fuel cells

Abstract

The energy conversion efficiency of air-cathode microbial fuel cells (MFCs) is limited by the cathode redox reaction (ORR). Consequently, the development of efficient catalysts is essential to enhance their catalytic activity in the oxygen reduction reaction, thereby improving the power output of MFCs. In the present analysis, a single-step hydrothermal method was used to synthesize a CCS-M catalyst with excellent catalytic performance (M is the ratio of copper source to cobalt source, M = 0.5, 1, 2). Through systematic optimization of the component ratio, the best performance was achieved when the molar ratio of the elements was set to 0.5. The enhanced catalytic performance of the CCS-0.5 catalyst can be largely ascribed to the cooperative effect between Cu and Co ions in the synthesized material. The incorporation of Co not only ensures a high density of active sites, but also reinforces the structural integrity of the nanomaterial, resulting in a flower-like architecture composed of stacked nanosheets. This multilayered sheet structure facilitates the comprehensive exposure of the active sites and accelerates the transport of electrons and oxygen, thus enhancing the ORR performance. In practical application tests, the CCS-0.5 catalyst demonstrated optimal output performance in MFCs, achieving a maximum power density of 200.08 mW m⁻² and a maximum output voltage of 354 mV, with stable performance over prolonged operation. This study provides new opportunities for designing metal sulfides as ORR catalysts and exploring their potential as cathode materials in MFCs.