Role of platinum-like tungsten carbide as cocatalyst of CdS photocatalyst for hydrogen production under visible light irradiation

To investigate the role of platinum-like tungsten carbide as a cocatalyst for photocatalytic hydrogen production under visible light irradiation, we fabricated for the first time a composite material consisting of WC and CdS by a precipitation/hydrothermal method. The composite prepared by this procedure consisted of well-dispersed WC and CdS, as confirmed by TEM mapping analysis. The WC/CdS composite photocatalyst exhibited a high rate of hydrogen production, comparable to that of Pt/CdS, under visible light irradiation (lambda >= 420 nm) from water containing sulfide and sulfite ions as hole scavengers. Like Pt cocatalyst loaded on the surface of CdS, WC provides active sites for proton reduction and causes fast diffusion of photoelectrons generated from CdS toward WC, leading to high photocatalytic activity of hydrogen production. (C) 2008 Elsevier B.V. All rights reserved.