Carbon nanotubes as catalysts for direct carbohydrazide fuel cells

As an alternative to potentially carcinogenic hydrazine for fuel cell application, carbohydrazide, which contains lone electron pairs on nitrogen atoms and readily activated N–H bonds, can be catalytically oxidized over metal-free carbon catalysts due to the high equilibrium electromotive force (1.65 V) of its oxidation reaction. Carbon nanotubes are found to electrochemically catalyze the carbohydrazide oxidation reaction more efficiently than carbon black and multi-layer graphene in alkaline media. With carbon nanotubes as the anode catalyst, anode metal-catalyst-free and completely metal-catalyst-free direct carbohydrazide anion exchange membrane fuel cells are shown here to generate a peak power density of 77.5 mW cm−2 and 26.5 mW cm−2, respectively.