Photocatalytic selective oxidation of benzyl alcohol over ZnTi-LDH: The effect of surface OH groups

Abstract

ZnTi-LDH nanosheets have been synthesized as photocatalysts for selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) under visible light irradiation. Based on UV–vis DRS, in-situ FTIR and XPS results, it was revealed that BA would be efficiently chemisorbed and activated on ZnTi-LDH forming the surface coordination species, which contributed to harvesting visible light and induced the photocatalytic reaction. The ESR spectra suggested that oxygen vacancies would be produced in ZnTi-LDHs after the adsorption of BA molecules. More exposed surface OH groups would induce more oxygen vacancies, which would serve as the centers for capturing photoelectrons from the photoexcited surface coordination species and act as active sites for enhanced O2 adsorption and activation, resulting outstanding photocatalytic activity. Finally, a possible mechanism was proposed to illustrate the photocatalytic process which mediated by surface coordination species formed by the interaction between ZnTi-LDH and BA.