HYDROGEN EVOLUTION OVER A POWDERED SEMICONDUCTOR PHOTOCATALYST

Hydrogen evolution from a liquid water-methanol mixture that dispersed with semiconductor photocatalyst Pt/TiO2 (anatase) powders was studied experimentally. The hydrogen evolution rates under various conditions are compared, and the mechanism involved in the rapid degradation of the activity of the catalyst is suggested on the basis of some factors that affect the activity of the catalyst. The rates of hydrogen evolution over catalysts of various shapes, i.e., colloid, porous particle, and thin film, are compared with respect to the morphology of the catalysts. A recommendation is made about the use of the porous catalyst, which has a surface area larger than its light-absorbing area and maintains a high catalyst activity over a long period of time. Hydrogen evolved in the solar collector in response to solar power with about a 15-min time lag.