Nano-molybdenum carbide/carbon nanotubes composite as bifunctional anode catalyst for high-performance Escherichia coli-based microbial fuel cell

• Nano-Mo2C/CNTs composite was used as bifunctional anode electrocatalyst for microbial fuel cell.
• CNTs are biocompatible and facilitate electron transfer via c-type cytochrome and nanowires.
• Nano-Mo2C exhibits electrocatalytic activity towards the oxidation of metabolite hydrogen.
• Composite yields a comparable activity to platinum as anode catalyst of microbial fuel cell.

A novel electrode, carbon felt-supported nano-molybdenum carbide (Mo2C)/carbon nanotubes (CNTs) composite, was developed as platinum-free anode of high performance microbial fuel cell (MFC). The Mo2C/CNTs composite was synthesized by using the microwave-assisted method with Mo(CO)6 as a single source precursor and characterized by using X-ray diffraction and transmission electron microscopy. The activity of the composite as anode electrocatalyst of MFC based on Escherichia coli (E. coli) was investigated with cyclic voltammetry, chronoamperometry, and cell discharge test. It is found that the carbon felt electrode with 16.7 wt% Mo Mo2C/CNTs composite exhibits a comparable electrocatalytic activity to that with 20 wt% platinum as anode electrocatalyst. The superior performance of the developed platinum-free electrode can be ascribed to the bifunctional electrocatalysis of Mo2C/CNTs for the conversion of organic substrates into electricity through bacteria. The composite facilitates the formation of biofilm, which is necessary for the electron transfer via c-type cytochrome and nanowires. On the other hand, the composite exhibits the electrocatalytic activity towards the oxidation of hydrogen, which is the common metabolite of E. coli.