Interfacial interactions of polyoxometalate and Au0Pdδ+ alloy boosting aerobic oxidation of alcohols

It is significant to gain insights into the electronic interfacial interactions on non-reducible oxides as they can effectively improve the catalytic performance. Herein, we reported the fabrication of Au⁰Pd^δ+ alloy (average size: 1.9 nm) co-modified with Na₁₂[α-P₂W₁₅O₅₆] (P₂W₁₅) nanoclusters on aluminum oxide (denoted as AuPd/P₂W₁₅-Al₂O₃) by deposition–precipitation and covalent immobilization strategy. The as-prepared AuPd/P₂W₁₅-Al₂O₃ exhibited 92 % conversion, 96 % selectivity of benzaldehyde with the reaction rate of 4.9 × 10⁴h⁻¹ when applied for the selective oxidation of benzyl alcohol, which was superior to AuPd/Al₂O₃, Au/P₂W₁₅-Al₂O₃ and Pd/P₂W₁₅-Al₂O₃ catalysts. Such excellent catalytic performance can be ascribed to the fact that: the electrons transfer from P₂W₁₅ to Au⁰Pd^δ+ alloy resulted in the electron-rich Au⁰Pd^δ+ alloy species, and the enhanced interfacial interactions between Au⁰Pd^δ+ alloy and P₂W₁₅ nanoclusters facilitated activation of O₂ to generate superoxide radicals •O₂^–. Moreover, density-functional theory (DFT) calculation confirmed that the P₂W₁₅ clusters modulated the d-band center of Au⁰Pd^δ+ alloy and accelerated the adsorption of benzyl alcohol, O₂ activation and desorption of benzaldehyde.