Dual-Channel Charge Carrier Transfer in CsPbX₃ Perovskite/W₁₈O₄₉ Composites for Selective Photocatalytic Benzyl Alcohol Oxidation

The selective oxidation of benzyl alcohol to benzaldehyde using oxygen (O2) as the oxidant is a reaction of critical importance in the organic industry. In this study, CsPbX3/W18O49 composites with varying band gap energies were synthesized using an in situ solvothermal method. The abundant oxygen vacancies in W18O49 extend the light response of the composite materials to the yellow and red part of the visible light region and result in a localized surface plasmon resonance (LSPR) effect, boosting the charge transfer. The composites exhibit high selectivity (>99%) and a conversion up to 72%, which is 11, 10, and 2.5 times higher than that of pure CsPbCl3, CsPbBr3, and W18O49, respectively. The composites’ boosted photocatalytic activity is related to a highly efficient dual-channel charge carrier transfer, governed by both a type-II heterojunction mechanism as well as the LSPR effect.