In situ synthesis of dual-functional photocatalyst xBi0/BiVO4 for the selective oxidation of cinnamaldehyde to benzaldehyde under visible light using oxygen

Abstract

The demand for natural benzaldehyde in fragrances and pharmaceuticals exceeds its supply because of consumer habits and stringent regulations. Sustainable development necessitates using eco-friendly methods for synthesizing organic compounds. This study investigates the selective photocatalytic oxidation of cinnamaldehyde to benzaldehyde using oxygen. Dual-functional xBi⁰/BiVO₄ photocatalysts were prepared in situ by tuning the Bi/V molar ratio. xBi⁰/BiVO₄ retained the photosensitizer properties of BiVO₄, while Bi deposition on BiVO₄ enhanced the generation of photogenerated electrons and the adsorption capacity for oxygen and cinnamaldehyde. The catalysts rapidly converted adsorbed oxygen into singlet oxygen, which contributed to the selective oxidation of cinnamaldehyde, achieving a benzaldehyde selectivity of 47–59%. Photogenerated electrons facilitated the formation of superoxide radicals, improving benzaldehyde selectivity and counteracting deactivation for sustained xBi⁰/BiVO₄ activity. In this study, we synthesized an efficient and durable photocatalyst for oxidizing CC bonds in α,β-unsaturated aldehydes, addressing limitations of existing photocatalytic processes.