Extremely sensitive and accurate HS sensor at room temperature fabricated with In-doped CoO porous nanosheets.

A facile hydrothermal method to prepare In-doped CoO porous nanosheets is reported in this paper for the first time. The prepared samples were made into gas sensors, and their sensing properties, such as response, response time, recovery time, selectivity and stability, have been researched systematically. These results indicate that the sensor fabricated with 1.0 at% In-doped CoO porous nanosheets shows a high response of 6.81 to 50 ppm and an obvious response of 1.4 to 1 ppm HS. What's more, this sensor exhibited a high selectivity and outstanding long-term stability toward HS. The excellent gas sensing performance was mainly ascribed to two reasons. (i) Doping with In increases the concentration of charge carriers, oxygen-deficient regions and the chemisorbed oxygen, which enhances the gas response. (ii) The rough porous structure is conducive to gas adsorption and capture, and provides many active sites for the sensing reaction. Therefore, 1.0 at% In-doped CoO porous nanosheets could be used as a sensing material in future applications.