Photothermal synergistic engineering of CeO2 and Au co-modified VO2 for efficient and selective oxidation of aromatic alcohols

Abstract

The reactions of selective aromatic alcohol oxidation are of great significance to basic research and industrial production, yet still facing some challenges, such as harsh reaction conditions, complex reaction systems and environmental pollution. Herein, Au/VO2/CeO2 (AVO/CeO2), a novel photothermal catalyst was designed for the selective oxidation of aromatic alcohols to aromatic aldehydes. Under atmospheric pressure, the optimized 10% A(0.1%)VO/CeO2 (0.1% Au/VO2 denoted as A(0.1%)VO) displays a yield up to 2726.92 μmol/g/h and a selectivity over 99%. A possible photothermal synergistic catalysis mechanism was also proposed on the base of the physical and chemical characterizations and theoretical calculation results. In the thermal cycle process following Mars-vanKrevelen mechanism, the V5+ and Ce4+ oxidized aromatic alcohols into aromatic aldehydes, and the generated V4+ and Ce3+ were oxidized back to V5+ and Ce4+ by the adsorbed oxygen. In the photocatalytic process, the adsorbed oxygen combined with the photogenerated e– derived from CeO2 to generate •O2– and separated the photogenerated charge effectively. Together with the adsorbed oxygen, •O2– and h+ participated in oxidizing V4+, which further enhanced the aromatic alcohols oxidation. Moreover, the introduced Au nanoparticles further accelerated the separation and transport of photogenerated charge, thus improving the photooxidation performance.