Stable Ti3+ Self-Doped Anatase-Rutile Mixed TiO2 with Enhanced Visible Light Utilization and Durability

Blue Ti3+ self-doped TiO2 nanoparticles with mixed phases of anatase and rutile have been synthesized via a facile solvothermal method. The phase evolution of the blue TiO2 varying from anatase to rutile has been studied by simply controlling the initial volume ratios of TiCl3 to titanium isopropoxide in the reaction solutions. The blue TiO2 has a distinct improvement of visible light harvesting and remarkable enhancement in photocatalytic activity, which could be ascribed to the presence of Ti3+ centers and the synergetic effect between the two phases. In addition, the as-prepared blue TiO2 shows an excellent stability during the photocatalytic reactions. A photocatalytic mechanism of the self-doped blue TiO2 was proposed at last.