Nanorod tungsten carbide thin film and its electrocatalytic activity for nitromethane electroreduction

Tungsten carbide has a unique advantage of resisting catalysts poisoning, such as carbon monoxide, hydrocarbons, and hydrogen sulfide, but its catalytic activity is much less than that of platinum. How to improve its catalytic activity is the key problem for realization in practical usage and replacement of platinum catalyst. The nanorod tungsten carbide (NR-WC) thin film was deposited on nickel substrate by magnetron sputtering. SEM results showed that these thin films were composed of uniform nanorods with a diameter of around 70 nm, a height of around 200 nm. The main components of the thin film are WC1−x. Electrocatalytic properties and reaction mechanism of nitromethane electroreduction on the NR-WC thin film electrode were investigated by electrochemical methods. Results indicated that the electrode showed a good electrocatalytic activity, current peak of 14.9 mA cm−2 of nitromethane electroreduction appeared at potential of −0.89 V (Vs. SCE) and the reaction activation energy was 12.3 KJ mol−1. Electrocatalytic activity of the NR-WC thin film electrode is approached to that of the Pt foil electrode. The electrocatalytic reduction of nitromethane on the NR-WC thin film electrode is an irreversible reaction, and the control step of electroreduction is mass transfer process.