Activating Pd Nanoparticles on Oxygen-Doped g‑C3N4 for Visible Light-Driven Thermocatalytic Oxidation of Benzyl Alcohol

Direct oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) using O2 as the oxidant has crucial significance under mild conditions in industrial manufacturing. Herein, an efficient and ecofriendly Pd/O-g-C3N4 heterojunction catalyst using oxygen-doped g-C3N4 (O-g-C3N4) with a porous surface as the support is developed for visible light-driven thermocatalytic oxidation of BzOH to BzH by using O2 as the sole oxidant. The obtained Pd/O-g-C3N4 exhibits visible light-enhanced catalytic performance under visible light irradiation with BzOH conversion and BzH yield of 89.4 and 76.6%, respectively, which are 1.96 and 1.83 times higher than those for the catalyst in the dark. Oxygen doping, as well as Pd deposition, can significantly narrow the band gap of g-C3N4, thereby enhancing its visible light harvesting ability. The resulting heterojunction interface between Pd nanoparticles and O-g-C3N4 might promote separation of the photogenerated e––h+ pairs. In addition to achieving considerable BzOH conversion and BzH yield, Pd/O-g-C3N4 also exhibits impressive stability. The current study provides potential applications for the green and efficient catalytic oxidation of other alcohols to corresponding aldehydes using O2 as the oxidant.