Effect of ethylene glycol chelated on ultrathin TiO2(B) nanosheets on the photocatalytic selective benzyl alcohol oxidation

The two-dimensional (2D) photocatalysts have been paid intensive attention in catalysis due to their excellent activity, which was greatly improved by the higher exposure of active sites and a facile reaction platform, and the separation efficiency of charge carriers. Herein, TiO2(B) nanosheets, which were synthesized via solvothermal method in ethylene glycol, could photocatalytically oxidize benzyl alcohol to benzaldehyde with high selectivity. The study revealed that the material's photocatalytic performance is highly influenced by the surface-chelated ethylene glycol. The pristine TiO2(B) was effective in selectively photocatalytic oxidizing benzyl alcohol, achieving a 94.5 % conversion, while the conversion decreased to 55 % after the elimination of the surface ethylene glycol. The presence of ethylene glycol on the surface of TiO2(B) nanosheets benefits the transfer of photogenerated charge carriers and improves charge separation efficiency. It is favorable for the selective formation of singlet oxygen (1O2) species, which results in enhanced photocatalytic activity and selectivity. We believe that our findings can shed light on the importance of the surface species and properties of photocatalysts in photocatalysis, and pave an avenue for the design and preparation of high-efficiency photocatalysts with unique surface properties.