Mild Hydrodeoxygenation of Aromatic Ketones by Pd/H_<i>x</i>WO_3–<i>y</i> with Plasmonic Features Assisted by Visible-NIR Light Irradiation

Abstract

Hydrodeoxygenation (HDO) reactions are important processes in the fields of bioenergy and biorefining, as they enable the conversion of biomass into valuable products that can replace fossil fuels and reduce greenhouse gas emissions. The efficient utilization of solar energy for boosting HDO reactions is of great significance for achieving ecological chemistry in a sustainable manner. However, the application of photocatalysts is severely restricted by inadequate utilization of the solar spectrum, rapid recombination of photogenerated carriers, and slow catalytic kinetics. Here, we demonstrate that the Pd/HxWO3–y catalyst prepared by a facile H2 reduction process displays efficient catalytic activity in the HDO of benzophenone to diphenylmethane with the aid of light irradiation owing to its surface plasmon resonance (SPR) effect. The H2 reduction process forms a large number of hydroxyl groups and a trace of oxygen defects on the Pd/WO3 surface, and the intercalated H atoms enrich the Pd/HxWO3–y surface with a large number of free electrons, resulting in plasmonic absorption under visible-NIR irradiation. Photoelectrochemical characterization and in situ Fourier transform infrared (FT-IR) spectroscopy indicate the photogenerated hot electron generation and electric field enhancement effect on the catalyst surface during the photoassisted reaction, which promotes H2 activation and CO bond activation to enhance the HDO reaction’s efficiency. This experiment establishes a feasible approach to effectively utilize solar energy in the HDO reaction of ketones under mild conditions by creating an intriguing field of catalysis on Pd/HxWO3–y with plasmonic features