Fabrication of photocatalytic coatings by sol thermal spray

摘要

Photocatalytic TiO_2 coatings were deposited by a conventional flame spray technique. Two kinds of sol were prepared by hydrolysis of titanium alkoxide in ethanol or 1,3-butanediol as solvents. The prepared sols were injected in propane-air flame from above. The observation of coatings' microstructure, identification of crystalline phases, and evaluation of photocatalytic activities by decomposition of acetaldehyde gas were carried out. In this study, the effects of sol preparing and thermal spraying conditions on photocatalytic activities were investigated. In case of ethanol solvent, less cracks were observed on the surface of coatings than that of 1,3-butanediol solvent and anatase phase detected in the coatings deposited with high sol supply rate. Moreover, the coatings deposited by using sol in ethanol solvent exhibit much higher photocatalytic activities than that in 1,3-butanediol solvent, because the evaporation enthalpy of ethanol is lower than that of 1,3-butanediol. And photocatalytic activities of coatings increased with increasing supply rate of sol in ethanol solvent.