Photocatalytic oxidation of acetaldehyde by hybrid Pt/WO3-MOR photocatalysts under visible or sunlight irradiation

A hybrid photocatalyst was prepared from visible light-responsive Pt/WO3 and siliceous mordenite (MOR) zeolite by simple impregnation with an aqueous solution of (NH4)(10)W12O41 center dot 5H(2)O. Unmodified Pt/WO3 had low photocatalytic activity in gas phase oxidation of acetaldehyde because of its low surface area (3-5 m(2)/g). In contrast, the Pt/WO3-MOR had higher photocatalytic activity under focused sunlight and Xe lamp irradiation. Pt/WO3-MOR with low WO3 content (< 20 wt%) adsorbed sufficient acetaldehyde, but absorption of light in the visible region was low. The optimum zeolite content enhancing the photocatalytic activity of Pt/WO3 was estimated to be 30-50 % (w/w). Adsorption of the gaseous reactants and the efficiency of absorption of incident light are both important aspects of high photocatalytic activity.