Abstract
Photocatalytic production of H_2 from aqueous solution of ethanol was studied using Pt/TiO_2 photocatalysts prepared by sonochemical reduction method. Aqueous solutions of chloroplatinic acid and polyethylenglycol monostearate were sonicated under argon atmosphere (200 kHz, 6 W/cm2) for 30min to form Pt colloidal dispersion. This dispersion was mixed with TiO_2 (better than 99.5%, P-25, Japan Aerosil Co. ) and followed by extended sonication. After filtration and drying(50℃, 12h), Pt nanoparticle supported TiO_2 was obtained. Beside sonochemical method, conventional impregnation method was also employed to prepare samples. Obtained samples were dispersed in an aqueous solution containing ethanol. The suspension was purged of air with argon flow and illuminated by amercury xenon lamp and generated H_2 was monitored. In the case of TiO_2 only, the generation of H_2 was hardly detected. When Pt nanoparticles were supported on the surface of TiO_2, the activities were enhanced probably due to the restrain effect of Pt for the recombination of holes and electrons. It was clear that the sonochemical catalysts showed higher activities than the conventional ones.
