Carboxyl Multi-Wall Carbon Nanotubes Supported Pt-Ni Alloy Nanoparticles as Cathode Catalyst for Microbial Fuel Cells

This work discusses a low-cost and high performance catalyst of the oxygen reduction reaction (ORR) in microbial fuel cells (MFCs). The catalyst was formed by Pt–Ni (15 wt% Pt) nanoparticles dispersed on carboxyl multi-wall carbon nanotubes (Pt-Ni/MWNT). The catalyst particle presents a nano- crystalline structure and has an average diameter of ca.7.1 nm based on the X-ray diffraction and transmission electron microscopy measurement. The electrocatalytic stability and activity of the catalyst was evaluated by cyclic voltammogram and chronopotentiometry. The MFC with a Pt-Ni/MWNT cathode produced a maximum power density of 1.22 W/m 2 , which was close to that with a Pt/C (20 wt% Pt) cathode (1.40 W/m 2 ); the Coulombic efficiency reaches 31.6%, which was better than that of the Pt/C (29.3%). The total cost of a Pt-Ni/MWNT catalyst was much lower than that of a Pt/C catalyst. Thus, the Pt-Ni/MWNT probably provides a new solution for finding effective cathode materials for MFC.