“…After some 30 years of extensive research, many oxide compounds of semiconductor photocatalysts include TiO 2 , ZnO, WO 3 , SnO 2 , and ZrO 2 , and some of the sulfide compounds like CdS, ZnS are among those most interesting materials in this respect [5]. Within these compounds, titanium oxide has also been investigated for its photocatalytic activities [6,7] and for use in photoelectrochemical cells as well [8]. It has drawn great attention in research and industrial fields in recent years because of its characteristics of powerful oxidation capability, non-toxicity, chemical stability, and cost-effectiveness.…”