The heat treatment in carbon powder is a safe and effective strategy to enhance the photocatalytic activity of titanium dioxide (TiO2) coatings. Firstly, Ti coatings were prepared by mechanical coating operation with Ti powder on alumina balls. Secondly, the target TiO2 coatings were prepared using the prepared Ti coatings by the multi-heat treatment (pretreatment in carbon powder, oxidation in air and reduction in carbon powder). During the pretreatment, thin films of Ti2CO and micro-cracks form in the surface of the Ti coatings. The formed thin films and micro-cracks are helpful for forming a nano-fiber morphology of rutile TiO2, during the subsequent oxidation. During the reduction, oxygen vacancies generated in the lattice of rutile TiO2 are in favor of narrowing the band gap. The target TiO2 coatings with a nano-fiber morphology and the narrowed band gap, effectively enhances the photocatalytic activity by more than 3 times, compared with the pristine TiO2 coatings.
Heat treatment effect of a hybrid consisting of SnO2 nanorod and rutile TiO2 with heteroepitaxial junction on the photocatalytic activity
