Preparation of nano-crystalline tungsten carbide thin film electrode and its electrocatalytic activity for hydrogen evolution

Nano-crystalline tungsten carbide thin films were fabricated on pure flake Ni and foam Ni substrates by plasma enhanced chemical vapor deposition. SEM results showed that the films were composed of uniform grains with a diameter of around 10 nm. The electrocatalytic properties of the film for hydrogen evolution reaction in alkaline solutions were investigated. The film showed an attractive catalytic activity in hydrogen evolution. The exchange current density of hydrogen evolution reaction was 4.02-4.22 x 10(-4) A cm(-2). When the over-potential was 263 mV, the activation energy of hydrogen evolution was 45.62-45.77 kJ mol(-1). Nano-crystalline WC thin film electrode had a high catalytic stability according to the result of cyclic voltammetry. (c) 2005 Elsevier B.V. All rights reserved.