CsPbBr₃/Polyoxometalate Composites for Selective Photocatalytic Oxidation of Benzyl Alcohol

Selective oxidation of benzyl alcohols to the corresponding carbonyl compounds is of great importance for providing versatile intermediates for the synthesis of pharmaceuticals and fine chemicals. In this work, we constructed a CsPbBr₃/[Ni₄(H₂O)₂(PW₉O₃₄)₂]^10- (CsPbBr₃/Ni₄P₂) composite by integrating the visible light-responsive ability of CsPbBr₃ and the multielectron-transfer ability of polyoxometalates. The resulting CsPbBr₃/Ni₄P₂ composite exhibited good photocatalytic activity toward the selective conversion of benzyl alcohol to benzaldehyde with ∼100% selectivity. Mechanistic studies revealed that the tetra-nickel-substituted polyoxotungstate, Ni₄P₂, played crucial roles in the separation/migration and utilization of photogenerated charge carries due to its well-matched energy level with that of CsPbBr₃ and the distinctive electron/proton-transferring ability as a redox shuttle. Multiple scavenging experiments confirmed that the photogenerated electrons (e^-), holes (h⁺), ^•O₂^-, and ¹O₂ were key reactive species for efficient photocatalysis.