Fabrication of oxygen-deficient TiO2 coatings with nano-fiber morphology for visible-light photocatalysis

In this study, heat treatment in carbon powder is developed as a safe, simple, and effective strategy to fundamentally enhance the visible-light photocatalytic activity of titanium dioxide (TiO2) coatings. The target TiO2 coatings were fabricated using the prepared Ti coatings by a heat treatment process involving pretreatment in carbon powder, followed by oxidation in air, and reduction in carbon powder. The results show that Ti2CO coatings are formed and micro-cracks appear in the surface of the coatings during pretreatment. The Ti2CO coatings and micro-cracks are beneficial for forming rutile TiO2 coatings with nano-fiber morphology during subsequent oxidation. During reduction, oxygen vacancies, which promote the narrowing of band gap, are generated in the lattice of rutile TiO2. The visible-light photocatalytic activity of the target TiO2 coatings is effectively enhanced more than 8 times, compared with the TiO2 coatings prepared solely by oxidation of Ti coatings. The ability to fabricate highly visible-light photoactive TiO2 materials by simple and safe heat treatment in carbon powder opens up new opportunities in various areas, such as the preparation of powders, nanowires, films. (C) 2015 Elsevier Ltd. All rights reserved.