Zn-doping mediated formation of oxygen vacancies in SnO2 with unique electronic structure for efficient and stable photocatalytic toluene degradation

Abstract

To optimize the electronic structure of photocatalyst, a facile one-step approach is developed for the simultaneous realization of Zn-doping and surface oxygen vacancies (SOVs) formation on SnO2. The Zn-doped SnO2 with abundant SOVs exhibits efficient and stable performance for photocatalytic degradation of toluene under both low and high relative humidity. Experimental and theoretical calculations results show that the synergistic effects of Zn-doping and SOVs on SnO2 can considerably boost the charge transfer and separation efficiency. Utilizing the in situ DRIFTS and theoretical calculations methods, it is revealed that the benzene ring of toluene is opened at benzoic acid on the SnO2 surface and selectively at benzaldehyde on the Zn-doped SnO2 surface. This implies that Zn-doped SnO2 photocatalysts shorten the pathway of toluene degradation, and toxic intermediates can be significantly inhibited. This work could provide a promising and sustainable route for safe and efficient removal of aromatic VOCs with photocatalytic technology.