Selective oxidation of polyols to primary hydroxyl acids by plasmonic catalysis on an Au–Pt nanoalloy irradiated by visible light

Abstract

The integration of plasmonic metals with active transition metal-based catalysts has the potential to expand the range of chemical reactions feasible through plasmonic photocatalysis. This study reports a photocatalyst combining plasmonic Au and catalytically active Pt in the form of an Au–Pt nanoalloy supported on ZrO₂ nanopowder. This photocatalyst operates more effectively and selectively for the oxidation of polyols under visible light illumination than under conventional conditions, demonstrating a promising green process. By meticulously contrasting the photoelectronic properties, optical absorption, and in situ characterization of the catalyst, we have been able to substantiate the synergistic and plasmonic effect that enhances reaction efficiency. Light-excited hot electrons were observed to enhance the adsorption of oxygen by the photocatalyst, thereby accelerating the formation of ˙O₂⁻. Intense electromagnetic near fields generated at the illuminated plasmonic photocatalyst were observed to significantly enhance the chemisorption of the reactant onto the catalyst surface and the desorption of products. This green photocatalytic procedure is effective in a continuous-flow reactor under ambient temperature, ambient pressure, and simulated sunlight irradiation, allowing for the gram-scale production of 0.58 g of glycolate from 0.62 g of ethylene glycol.