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

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.