Increasing oxygen vacancies at room temperature in SnO2 for enhancing ethanol gas sensing

Partially reduced SnO 2 was prepared by using NaBH 4 as reducer under room temperature. After NaBH 4 treatment, the oxygen vacancy density of SnO 2 was increased greatly. X-ray photoelectron spectroscopy, photoluminescence and electron paramagnetic resonance indicates that the obtained materials are characteristic of a high concentration of oxygen vacancies. Owing to increased oxygen vacancy concentration, these materials showed significantly high gas-sensing response to ethanol. Compared with the ethanol-sensing response value of 36.9 for pristine SnO 2 towards 300 ppm ethanol, the response value for the partially reduced SnO 2 is 120.3. This ethanol-sensing response enhancement may be attributed to the fact that the increased surface oxygen vacancy facilitates oxygen adsorption, and promotes chemical reaction on the surface.