Leaf-like carbon frameworks dotted with carbon nanotubes and cobalt nanoparticles as robust catalyst for oxygen reduction in microbial fuel cell

In this investigation, a double Zeolitic Imidazolate Frameworks (ZIF) precursor is used to synthesize a leaf-like cobalt/nitrogen co-doped porous carbon embedded with carbon nanotubes (Co-N-PC@CNTs), as a catalyst to modify an activated carbon air cathode microbial fuel cell (MFC). The unique leaf structure of carbon frameworks, which is rich in carbon nanotubes and cobalt nanoparticles on the surface, is confirmed to accelerate the oxygen reduction reaction (ORR) through a four-electron pathway similar to Pt/C. The time-current test reveals the remarkable stability of indicated by the retain of around 92% current after 12 h. The electrochemical reactions with Co-N-PC@CNTs are far superior to the control group. What's more, the best improved MFC exhibits outstanding exchange current density (27.83 x 10(-4) A cm(-2)), and the optimized power density of MFC reaches 2479 +/- 70 mW m(-2), which is 247.2% higher than that of the control group (714 +/- 59 mW m(-2)). In addition, Co-N-PC@CNTs modified activated carbon cathode MFC has an excellent chemical oxygen demand (COD) removal rate of 86.52%, which is significantly better than the control group (50.51%). Therefore, Co-N-PC@CNTs is considered to be a promising MFC cathode catalyst.