Synthesis, surface chemistry and electrocatalytic properties of oxygen-modified tungsten carbide in relation to the electrochemical hydrogen oxidation

The surface chemistry of tungsten carbide was studied using an indicator spectrophotometric method and X-ray photoelectron emission spectroscopy. The presence of WO2, WO3 and adsorbed polytungstate ions was identified on the surface of WC specimens. The electrocatalytic activity of oxygen-modified tungsten carbide was attributed to the WO2 at their interface with WC. This conclusion is supported by the presence of some density of states of the 5d, 6s electrons at the Fermi level on the W4+ and by the relationship between exchange current density and concentration of the lattice O2−. Insertion of oxygen atoms in the WC crystal lattice leads to a widening of the anodic range of potentials in which the WC maintains its electrochemical activity in hydrogen oxidation reaction.