Promoting Catalytic Oxygen Activation by Localized Surface Plasmon Resonance: Effect of Visible Light Pre-treatment and Bimetallic Interactions

Visible light pre-treatment has been found to be capable of enhancing the catalytic oxygen activation on AuPt/TiO2 by up to seven times. Visible light pre-treatment exploits the localized surface plasmon resonance effect of Au to generate free electrons, which are transferred to the Pt active sites. The electron transfer was evident from a change in Pt speciation observed from X-ray photoelectron spectroscopy, showing the presence of PtO after visible light pre-treatment. Photoluminescence spectroscopy was used to reveal the bimetallic synergistic enhancement, as indicated by an overall decrease in the charge recombination rate. Further examination revealed that a good bimetallic interaction is necessary to achieve the enhancement by visible light pre-treatment. Weak bimetallic interaction, such as the occurrence of element segregation in the bimetallic alloy, inhibits electron transfer from the Au to the Pt and increases electron recombination rates, diminishing the degree to which visible light pre-treatment improves catalytic performance.