CdS and Ti₃C₂ Quantum Dot-Modified TiO_2–x Nanotubes as Highly Efficient Photocatalysts for Selective Oxidation of Benzyl Alcohol to Benzaldehyde

At present, the photocatalytic selective oxidation of alcohols to corresponding aldehydes is still widely concerned. Therefore, it is a great challenge to explore photocatalysts with a high conversion rate and selectivity. Here, the composite photocatalyst CdS QDs/TiO 2– x /Ti 3 C 2 QDs was constructed by an electrostatic self-assembly method. TiO 2– x nanotubes (T x ) with oxygen vacancies were modified with CdS quantum dots (CS QDs) and Ti 3 C 2 quantum dots (TC QDs). The introduction of CS QDs can expand the range of light reception of the composite catalyst. TC QDs are a cheap material, and their existence can replace the cocatalytic effect of precious metal materials, as an electron collector can effectively transfer electrons to the surface of the composite catalyst and then accelerate the selective oxidation of benzyl alcohol (BA). As a result, the composite catalyst 7.5% CS QDs/T x /TC QDs can promote the conversion of BA to 98% and the formation selectivity of benzaldehyde (BAD) to 99% in the photocatalytic selective oxygen reaction of BA. Moreover, the composite catalyst has good cycle stability. Our work provides an idea for the further industrialization of BA oxidation.