Controllable Al2O3 coating makes TiO2 photocatalysts active under visible light by pulsed chemical vapor deposition

Abstract

TiO2 catalysts, modified by coating Al2O3, presented high visible-light photocatalytic activity. Al2O3 nano-films were successfully deposited onto TiO2 particles using AlCl3 as a precursor via the pulsed chemical vapor deposition process. And, the alumina was anchored onto TiO2 surface via Ti–O–Al bonds. The morphology, constitution, photocatalytic activity and photoelectrochemical performance of the Al2O3-coated TiO2 were characterized. Controllable Al2O3 coating increased the oxygen vacancies and hydroxyl groups, and induced the formation of surface disordered TiO2 layer, which enhanced light absorption, increased charge carrier separation and transfer efficiency, and surface redox efficiency. Therefore, the TiO2/Al2O3 catalyst obtained via the pulsed chemical vapor deposition technique may break through the limitation of the band gap, and the pulsed chemical vapor deposition provided an effective strategy for the TiO2 production with active defective sites.