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

Partially reduced SnO2 was prepared by using NaBH4 as reducer under room temperature. After NaBH4 treatment, the oxygen vacancy density of SnO2 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 SnO2 towards 300 ppm ethanol, the response value for the partially reduced SnO2 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. •SnO2 samples with high oxygen vacancy concentration were prepared at room temperature by a simple method.•The obtained defective SnO2 showed much higher ethanol gas sensing.•The enhanced gas-sensing property was attributed to the oxygen vacancies.