Phase role of white TiO2 precursor in its reduction to black TiO2

Black TiO2, which is a promising photocatalyst with enhanced visible light absorption, is a new semiconductor with a smaller band gap than white TiO2. The synthesis of black TiO2 has been focused on optimizing hydrogen treatment and exploring different reductants. However, in this work, it was experimentally demonstrated that the phase structure of white TiO2 precursor plays an important role in its reduction to black TiO2 by hydrogen treatment, namely, compared with anatase TiO2, rutile TiO2 is much easier to be reduced to black TiO2. This provides a new direction for synthesis approach of black TiO2. (C) 2019 Elsevier B.V. All rights reserved.