Ethanol-Quenching Introduced Oxygen Vacancies in Strontium Titanate Surface and the Enhanced Photocatalytic Activity

Modification of the surface properties of SrTiO 3 crystals by regulating the reaction environment in order to improve the photocatalytic activity has been widely studied. However, the development of a facile, effective, and universal method to improve the photocatalytic activity of these crystals remains an enormous challenge. We have developed a simple method to modify the surface environment of SrTiO 3 by ethanol quenching, which results in enhanced UV, visible and infrared light absorption and photocatalytic performance. The SrTiO 3 nanocrystals were preheated to 800 °C and immediately quenched by submersion in ethanol. X-ray diffraction patterns, electron paramagnetic resonance spectra, and X-ray photoelectron spectra indicated that upon rapid ethanol quenching, the interaction between hot SrTiO 3 and ethanol led to the introduction of a high concentration of oxygen vacancies on the surface of the SrTiO 3 lattice. Consequently, to maintain the regional charge balance of SrTiO 3, Sr 2+ could be substituted for Ti 4+. Moreover, oxygen vacancies induced localized states into the band gap of the modified SrTiO 3 and acted as photoinduced charge traps, thus promoting the photocatalytic activity. The improved photocatalytic performance of the modified SrTiO 3 was demonstrated by using it for the decomposition of rhodamine B and production of H 2 from water under visible or solar light. View Full-Tex