Interfacial synergism of Pd-decorated BiOCl ultrathin nanosheets for the selective oxidation of aromatic alcohols

Inspired by the distinct advantages of BiOCl(001) ultrathin nanosheets being rich in oxygen vacancies (V-O) and metal nanoparticles (NPs) with unique surface activity for the adsorption-activation of alcohols, metaldecorated BiOCl(001) ultrathin nanosheets were expected to exhibit enhanced photocatalysis for the selective oxidation of aromatic alcohols. Herein, a small quantity (1.5 wt%) of Au and Pd NPs were loaded on ultrathin BiOCl(001) nanosheets by photodeposition to obtain Au-BiOCl and Pd-BiOCl photocatalysts, respectively. Among the various photocatalysts including BiOCl ultrathin nanosheets, light-irradiated BiOCl ultrathin nanosheets, and metal-decorated BiOCl ultrathin nanosheets, the PdBiOCl sample displayed the highest photocatalytic activity for the oxidation of aromatic alcohols to the corresponding aldehydes under ambient conditions. According to a series of experimental analyses as well as the insights from the calculations, the enhanced photocatalysis of Pd-BiOCl was attributed to the remarkable interface cooperation by the electronic coupling between Pd and the BiOCl(001) surface, where the abundant VO sites of BiOCl(001) ultrathin nanosheets and the surface activity of Pd NPs synergistically promote the adsorption-activation of O-2 and alcohol molecules as well as facilitating the separation and transfer of photogenerated carriers. These findings highlight the synergistic effect of the metal-semiconductor interface on the photocatalytic oxidation of organic compounds and shed some light on the rational design of highly efficient photocatalysts for selective conversion processes with environmentally benign oxidants like O-2.