Elementary reactions in surface photocatalysis

Photocatalytic hydrogen evolution and organic degradation on oxide materials have been extensively investigated in the last two decades. Great efforts have been dedicated to the study of photocatalytic reaction mechanisms of a variety of molecules on TiO2 surfaces by using surface science methods under UHV conditions, providing fundamental understanding of surface chemical reactions in photocatalysis. In this review, we have summarized the recent progress in the studies of photocatalysis of several important species (water, methanol and aldehydes) on different TiO2 surfaces. The results of these studies have provided us deep insights into the elementary processes of surface photocatalysis and stimulated a new frontier of research in this area. Based on the results of these studies, a new dynamics based photocatalysis model is also discussed.