Gentle way to build reduced titanium dioxide nanodots integrated with graphite-like carbon spheres: From DFT calculation to experimental measurement

Extending the ultraviolet response of anatase TiO2 into visible light range and effectively decreasing the recombination rate of photo-generated carriers are vital to promote the practical applications in the fields of hydrogen generation and water pollutant treatment of TiO2-based photocatalysts. Here we present a mild way to build composite of partial reduced TiO2 nanodots coated graphite-like carbon spheres (g-CS@TiO2-x) via a green solvothermal approach with relative low temperature. The chemical structure and electronic property of 3D g-CS@TiO2-x composites have been investigated by DFT. Our DFT calculation results indicates that some mid-levels are formed between the CB and VB of TiO2-x, which is beneficial to its visible absorption ability. The calculation results also show that bridge of Ti-O-C formed between g-CS and TiO2-x may let the composite possesses superior charge separation property. The experimental results demonstrate that the obtained 3D g-CS@TiO2-x can serve as an effective visible light-driven photocatalyst for hydrogen production and organic pollutants degradation. The good visible light absorption introduced by Ti3+ and 3D g-CS, the well-known electron transfer capability of g-CS, the matched electron structures of TiO2-x and g-CS, and perfect interface between TiO2-x and g-CS (Ti-O-C bridge), efficiently boost visible light photocatalytic performance via one-level electron transfer process. (C) 2016 Elsevier B.V. All rights reserved.