Enhancing bimetallic synergy with light: the effect of UV light pre-treatment on catalytic oxygen activation by bimetallic Au–Pt nanoparticles on a TiO2 support

Abstract

UV light pre-treatment was examined as a means of enriching the catalytic activation of oxygen by bimetallic AuPt deposits loaded on TiO₂. The rate of catalytic oxygen activation was assessed by monitoring the rate of formic acid oxidation in an aqueous system. A catalytic synergy was observed to exist for the bimetallic AuPt on TiO₂ and was governed by the Au–Pt structure and ratio. The extent of the synergy was further enhanced upon UV light pre-treatment. Exceptional improvements in bimetallic catalysts are often simply attributed to a synergy effect, which is not necessarily well-understood. The Au–Pt bimetallic synergy and UV light pre-illumination phenomena were probed using high-end characterisation tools in conjunction with first principle calculations with the effects attributed to a combined influence of work-function difference and lattice mismatch between Au and Pt. Understanding the origin of bimetallic synergism is a critical step toward developing advanced catalysts.