Superhydrophilic wollastonite-nanoTiO2 composite photocatalyst prepared by a wet grinding method: The effects of carriers and their application in the self-cleaning coatings

A wollastonite-nanoTiO(2) composite (WOT-PC) was prepared by a facile mechanochemistry method, which is expected to improve the photocatalytic performance and its recycling ability. According to the results of photocatalytic degradation, the degradation extent of the 10 ppm (10 mg/L) methyl orange solution was 99% after 20 min UV irradiation, indicating the good photocatalytic performance of WOT-PC. The XPS results suggests that stable Ca-O-Ti and Si-O-Ti bind wollastonite and nanoTiO(2) together chemically. Furthermore, Ca-O-Ti may promote the separation efficiency of photoinduced electrons and holes during irradiation. To study the bending of energy structures of nanoTiO(2), UPS was used. The results showed a negative shift of the energy structure bands and a positive shift of the Fermi level to TiO2, revealing that electrons more easily move to the surface of TiO2 after wollastonite supports nanoTiO(2). The WOT-PC coating exhibits great self-cleaning ability because of its superhydrophilicity and photocatalytic performance, reflecting the promise of WOT-PC as an outdoor wall coating in practical applications.

Automated summary

The wollastonite-nanoTiO(2) composite, WOT-PC, exhibits promising photocatalytic performance and recycling ability due to the stable chemical binding of Ca-O-Ti and Si-O-Ti, as well as the promotion of electron-hole separation efficiency by Ca-O-Ti. UPS analysis suggests that electron movement to the surface of TiO2 is facilitated after wollastonite supports nanoTiO(2), leading to enhanced photocatalytic performance. The superhydrophilicity and self-cleaning ability of WOT-PC make it a potential candidate for outdoor wall coatings.