New Reaction Pathway Induced by Plasmon for Selective Benzyl Alcohol Oxidation on BiOCl Possessing Oxygen Vacancies

Abstract

Selective organic transformation under mild conditions constitutes a challenge in green chemistry, especially for alcohol oxidation, which typically requires environmentally unfriendly oxidants. Here, we report a new plasmonic catalyst of Au supported on BiOCl containing oxygen vacancies. It photocatalyzes selective benzyl alcohol oxidation with O₂ under visible light through synergistic action of plasmonic hot electrons and holes. Oxygen vacancies on BiOCl facilitate the trapping and transfer of plasmonic hot electrons to adsorbed O₂, producing •O₂^- radicals, while plasmonic hot holes remaining on the Au surface mildly oxidize benzyl alcohol to corresponding carbon-centered radicals. The hypothesized concerted ring addition between these two radical species on the BiOCl surface highly favors the production of benzaldehyde along with an unexpected oxygen atom transfer from O₂ to the product. The results and understanding acquired in this study, based on the full utilization of hot charge carriers in a plasmonic metal deposited on a rationally designed support, will contribute to the development of more active and/or selective plasmonic catalysts for a wide variety of organic transformations.