Bimetallic metal-organic frameworks derived cobalt nanoparticles embedded in nitrogen-doped carbon nanotube nanopolyhedra as advanced electrocatalyst for high-performance of activated carbon air-cathode microbial fuel cell

Abstract

A new type of nitrogen-doped carbon nanotube embedded cobalt nanoparticles nanopolyhedra (Co-NCNTNP) electrocatalyst synthesized via pyrolysis bimetallic metal-organic frameworks was investigated to modify the activated carbon air-cathode microbial fuel cell (MFC). X-ray diffraction and transmission electron microscope characterization confirmed the combination of nitrogen-doped carbon nanotube and transition metal element in Co-NCNTNP. Rotating disk electrode measurement revealed the oxygen reduction reaction (ORR) of as-prepared Co-NCNTNP was mainly proceeded via a four-electron pathway like Pt/C. When fabricated into activated carbon cathode, the optimized MFC reached the maximum power density of 2252 ± 46 mW m−2, which was 154% higher than that of control. Moreover, the resistance including total resistance and charge transfer resistance of modified cathode significantly decreased comparing to the control, which was beneficial to better MFC performance. Therefore, all attracting properties suggested that noble-metal-free and high-efficiency Co-NCNTNP could be considered as a Pt-alternative electrocatalyst for ORR in MFC.