Surface modification of TiO2 for visible light photocatalysis: Experimental and theoretical calculations of its electronic and optical properties

Abstract

Surface modification has been used as a method to create defects on [Formula: see text] materials, which can improve their desirable properties. In this paper, defected [Formula: see text] nano-powder was successfully synthesized by chemical reduction using [Formula: see text] as the reducing agent at 300–400[Formula: see text] under argon atmosphere. High defect concentration can be produced by increasing process temperature. The modified [Formula: see text] shows good visible light absorption and photocatalytic activity on degradation of Rhodamine B (4–9 times higher than the pristine [Formula: see text]) with the visible light irradiation. Further XPS analysis and theoretical studies using full potential linearized augmented plane wave (FP-LAPW) method as implemented in wien2k code revealed the existence of oxygen vacancy and [Formula: see text] in the modified samples. These types of defects were responsible for the modifications of the electronic and optical properties of [Formula: see text], resulting in the improved photocatalytic activity in visible light irradiation.