Influence of Annealing Treatment on the Photocatalytic Performance of the Nanostructured TiO2 Coating Deposited by Vacuum Cold Spray

摘要

Composite powder in sub-micrometer size was prepared using a primary nano-TiO2 powder and polyethylene glycol (PEG). The nano-TiO2 coating was deposited through vacuum cold spray using both the composite powder and primary nano- TiO2 powder. The influence of annealing treatment on coating adhesion and photocatalytic activity was investigated. The coating adhesion was estimated through erosion test by water jet. The photocatalytic performance of the TiO2 coatings was evaluated through photodegradation of phenol in water. The results showed that annealing of the coating at a temperature from 450 to 500 oC yielded both higher activity and better adhesion. The adhesion of the coating deposited using the composite powder was better than that using primary nano- TiO2 powder. It was found that TiO2 coating resulting from the composite powder presented much higher activity than that deposited with primary nano-particles. The better activity is attributed to the existence of large pores resulting from the stacking of composite powder, which benefits the reactants transportation through the porous coating.