Enhanced Interfacial Charge Transfer and Activation for Selective Oxidation of Benzyl Alcohol over Boron-doped Defect-Rich Fe3O4@B-CeO2/Au Photocatalyst.

Abstract

Selective oxidation of aromatic alcohols to their corresponding carbonyl compounds under mild conditions holds significant promise for industrial applications. However, the performance of photocatalysts is notably hindered by limited visible-light absorption, low charge separation and transfer efficiency, as well as weak adsorption and activation of aromatic alcohols and O2. In this study, we successfully synthesized a Boron-doped defect-rich Fe3O4@B-CeO2/Au photocatalyst for the selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) under visible light. Experimental results and density functional theory (DFT) calculations demonstrate that boron doping not only introduces a heteroatomic energy level that acts as 'intermediate springboards', significantly broadening the absorption range of visible light, but also creates abundant oxygen vacancies and acidic sites, benefiting the adsorption and activation of O2 and BA. Furthermore, the localized surface plasmon resonance (LSPR) effect of Au further improves the transport of interfacial photogenerated electrons. Due to these combined advantages, the selectivity of the Fe3O4@B-CeO2/Au photocatalyst for BAD reached 100%, and the conversion rate of BA was as high as 98.96% after 8 hours of reaction under visible light. Moreover, owing to the magnetic properties of the Fe3O4 core, the photocatalyst exhibits excellent operational and cyclic stability.