Ultrathin HNb3O8 nanosheets with oxygen vacancies for enhanced photocatalytic oxidation ofamines under visible light irradiation

摘要

Ultrathin HNb3O8 nanosheets (HNb3O8 NSs) with oxygen vacancies were successfully synthesized by a simple bottom-up hydrothermal process. The obtained nanosheets were uniform with a thickness of about 3.02 nm and the surface oxygen vacancies on the HNb3O8 nanosheets were confirmed by electron spin resonance spectroscopy (ESR) and X-ray photoelectron spectroscopy (XPS). As compared to urchin-like Nb2O5 nanospheres and Nb2O5 nanorods, ultrathin HNb3O8 nanosheets with oxygen vacancies showed higher activities in the photocatalytic oxidative coupling reaction of benzylamine under visible light irradiation. The improved photocatalytic activity of HNb3O8 NSs was attributed to the following: (1) unique nanosheet structure with different molecular thicknesses that led to the effective separation of the photogenerated carriers; (2) a benzylamine-HNb3O8 surface complex formed on the oxygen vacancies, which reduced the bandgap of HNb3O8 NSs and was beneficial to harvest visible light; (3) HNb3O8 NS-V could efficiently chemisorb O-2 molecules and promote the activation of O-2 to reactive oxygen species.