Self-assembled monolayer-immobilized gold nanoparticles for WO3/TiO2 nanocomposite films to yield remarkably enhanced ultraviolet and visible-light photocatalytic activity

This study proposes a self-assembled monolayer nickel-seeding process to immobilize Au nanoparticles (NPs) onto WO3-containing mesoporous TiO2 films as superhydrophilic coatings for self-cleaning applications. Through the redox reactions between nickel seeds and HAuCl4, the loading of Au NPs is confirmed by X-ray photoelectron spectroscopy and transmission electron microscopy. The WO3/TiO2 film is visible-light inactive and displays sound superhydrophilic surface only under ultraviolet light irradiation. By contrast, the Au loaded WO3/TiO2 film under ultraviolet light irradiation has a much longer lifetime of superhydrophilic surface than the WO3/TiO2 film (>300 vs. 90 days); it also responds sharply to visible light, yielding a long, lasting superhydrophilic surface of up to 180 days. Surface plasmon resonance created by the loaded Au NPs is confirmed by light absorbance and Raman measurements, which allows for the proposal of a mechanism for the remarkable enhancement of ultraviolet and visible-light photocatalytic activity.

Automated summary

This study proposes a self-assembled monolayer nickel-seeding process to immobilize Au nanoparticles onto WO3-containing mesoporous TiO2 films as superhydrophilic coatings for self-cleaning applications. The loaded Au NPs on the film significantly enhance the superhydrophilicity and photocatalytic activity, and the mechanism is attributed to the surface plasmon resonance effect.