Abstract
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The potential for applying UV light pre-treatment to enhance the oxygen activation capacity of Au/TiO2
under ambient conditions was examined. Catalytic formic acid oxidation in an aqueous environment was
employed as the test reaction. Pre-illuminating Au/TiO2 with UV light can amplify the catalytic formic acid
oxidation rate by up to four times with the degree of enhancement governed by system parameters such
as Au loading, pre-illumination time, and initial formic acid loading. X-ray photoelectron spectroscopy,
photoluminescence spectroscopy and electrochemical assessment of the Au/TiO2 indicated light preillumination
invokes photoexcited electron transfer from the TiO2 support to the Au deposits. The Au deposits
then utilise the additional electrons to catalyse molecular oxygen activation and promote the oxidation
reaction. Scanning tunneling spectroscopy analysis and first principle calculations indicated the Au deposits
introduced new electronic states above the TiO2 valence band. The new electronic states were most
intense at the Au–TiO2 interface suggesting the Au deposit:TiO2 perimeter may be the key region for oxygen
activation. The current study has demonstrated that pre-illuminating Au/TiO2 with light can be used to
augment reactions where oxygen activation is a critical component, such as for the oxidation of organic
pollutants and for the oxygen reduction reaction in fuel cells or energy storage systems.