Structural, Optical, and Photocatalytic Properties of Cr:TiO2 Nanorod Array Fabricated by Oblique Angle Codeposition

A unique fabrication method, oblique angle codeposition (OACD), is used to deposit well-aligned arrays of Cr/TiO 2 composite nanorods (Cr:TiO 2 ) that exhibit optical absorption in the visible region. The effect of the Cr atoms on the structural, optical, and photocatalytic properties of TiO 2 has been investigated. The high Cr concentration (10 atom %) alters the TiO 2 lattice structure, with an increase in the crystallization temperature of the anatase phase and a decrease in the rutile crystallization temperature. Additionally, Cr is found to segregate out of the TiO 2 matrix and migrate to grain boundaries and the surface of the nanorods. The photocatalytic efficiency and photoelectrochemical performance for H 2 production of the Cr:TiO 2 films are reduced when compared to pristine TiO 2 due to the formation of surface and intergranular Cr(VI) oxide clusters, which act as recombination centers and cover catalytically active sites on the nanorod surface.