A new photocatalyst was prepared by loading 1 wt% of a platinum cobalt alloy on CdS via a simple polyol reduction method. XRD measurements confirmed the composition of the alloy as Pt3Co. Results from transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) measurements showed that Pt3Co nanoparticles with an average size of 4 nm were uniformly assembled on the surface of CdS. It was found that the activity of Pt3Co–CdS was approximately two times higher than that of Pt–CdS for photocatalytic H2 evolution. Photochemical measurements suggested that the high activity could be attributed to a better accumulation of photoexcited electrons and the higher conductivity of Pt3Co–CdS than that of Pt–CdS. The Pt3Co alloy cocatalyst was also loaded on TiO2, another widely used photocatalyst, and it also exhibited higher activity than pure Pt loaded on TiO2. This demonstrates the potential of Pt3Co as a universal cocatalyst.
