Cu, N-codoped carbon rod as an efficient electrocatalyst used in air-cathode for high performance of microbial fuel cells

Abstract In this work, a new type of rod-like copper and nitrogen co-doped carbon (Cu@N-C), using nitric acid treated Cu-MOF as a precursor, was served as a highly efficient oxygen reduction reaction electrocatalyst in microbial fuel cells with air cathodes. The maximum power density of Cu@N-C modified air cathode MFC was 1760 mW·m−2, almost 2 times higher than the control (Activated Carbon, AC). The electrochemical research showed that Cu@N-C doped AC cathodes exhibited higher kinetic activity of electron transfer and lower resistance via a 4-electrons transfer pathway like Pt/C. Cylindrical rod structure with homogeneous distribution of Cu, N and C was observed in Cu@N-C, which provided abundant active sites for electrocatalytic reaction. XPS and FTIR further testified the existence of redox electron pair (Cu2+/Cu+) and N element in the extended 3D rod-like frameworks, which was beneficial to MFC performance. The nitrogen adsorption-desorption characterization proved that the catalyst was a microporous material and the specific surface area of the catalyst was as high as 1397.75 m2 g−1, which provided efficient access and adsorption active sites for oxygen in ORR. Therefore, the synergistic effects between structural and electrochemical advantages of as-prepared Cu@N-C made it a promising catalyst for ORR in MFCs.