Deposition of photocatalytic TiO 2 coating by modifying the solidification pathway in plasma spraying

Abstract

The deposition of photocatalytic TiO 2 coatings with plasma spraying is attractive for large-scale applications due to its low cost and simplicity, but it is still a challenge to obtain a TiO 2 coating with high anatase content. The solidification pathway of inflight melted particles was investigated in the present paper, and TiO 2 coatings with enhanced photocatalytic activity were obtained without a significant loss of the microhardness. The coating microstructure, phase composition, and crystallite size were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Photocatalytic performance was evaluated by decomposing an aqueous solution of methylene blue. Results showed that the anatase content in TiO 2 coating was augmented to 19.9% from 4%, and the time constant of the activity was increased to 0.0046 h -1 from 0.0017 h -1 .