Transition metals (Co, Mn, Cu) based composites as catalyst in microbial fuel cells application: The effect of catalyst composition

Microbial fuel cell (MFC) is a novel electrochemical technique that can produce bioelectricity by electro-active bacteria, while the bioelectricity depends greatly on electrochemical activity of cathode catalyst. Here, some effective transition metal composites are synthesized by a facile hydrothermal method, and these composites are used as oxygen reduction electrocatalyst for enhancing power output in air cathode MFC. A series of structural characterizations suggest that CoN@C possesses abundant oxygen vacancies and pyridinic-N. Linear sweep voltammetry (LSV) analysis demonstrates CoN@C can take part in oxygen reduction reaction (ORR) through a 4e- transfer pathway. At a loading amounts of 5 mg cm(-2), CoN@C cathode can achieve the maximum power density (1202.3 +/- 18.6 mW m(-2)), which is 1.09 times higher than that of commercial Pt/C (1104.1 +/- 24.7 mW m(-2)). High power output of CoN@C-5 is ascribed to the introduction of pyridinic-N, abundant oxygen vacancies, and large electrochemical active area. Consequently, CoN@C composite is an effective cathode electrocatalyst to replace precious Pt/C for MFC application.