“…Since the discovery of its photoactivity by Fujishima and Honda [1], and owing to its exceptional properties, such as low cost, high stability, high chemical inertness, bio-compatibility, and non-toxicity, TiO 2 has been examined widely as an efficient photocatalyst material for purification of water, degradation of dyes and pesticides, etc [2][3][4]. However, the photocatalytic efficiency of TiO 2 is hampered by several obstacles such as wide band gap and easy recombination of photogenerated electron/hole pairs [5][6][7]. Numerous attempts have been made to overcome these problems including doping by metals or nonmetals [8][9][10][11][12], cocatalyst immobilization [13], and controlled faceting [14].…”