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

摘要

Composite powder in sub-micrometer size was prepared usinga primary nano-TiO2 powder and polyethylene glycol (PEG).The nano-TiO2 coating was deposited through vacuum coldspray using both the composite powder and primary nano-TiO2 powder. The influence of annealing treatment on coatingadhesion and photocatalytic activity was investigated. Thecoating adhesion was estimated through erosion test by waterjet. The photocatalytic performance of the TiO2 coatings wasevaluated through photodegradation of phenol in water. Theresults showed that annealing of the coating at a temperaturefrom 450 to 500 °C yielded both higher activity and betteradhesion. The adhesion of the coating deposited using thecomposite powder was better than that using primary nano-TiO2 powder. It was found that TiO2 coating resulting fromthe composite powder presented much higher activity than thatdeposited with primary nano-particles. The better activity isattributed to the existence of large pores resulting from thestacking of composite powder, which benefits the reactantstransportation through the porous coating.