Facile Synthesis of Template-Free SnS2 with Different Morphologies and Excellent Gas-Sensing Performance for NO2 Gas-Sensor Applications

Abstract

© 2022 Wiley-VCH GmbH. Herein, SnS2 particles with two different morphologies are synthesized using a template-free one-step hydrothermal method. Flower- and plate-like SnS2 are obtained using different solvents, ethyl alcohol, and deionized water, respectively, under the same synthesis conditions. The flower-like SnS2 had a larger surface area and higher concentration of sulfur vacancies than plate-like SnS2. The effects of the specific surface area and the number of sulfur vacancies in the gas-sensing materials are studied using the gas-sensing characteristics of SnS2 in the two morphologies. The gas sensitivities at 25 °C under 1 ppm NO2 are 73.5 and 129.5 for flower- and plate-like SnS2, respectively. Both the flower- and plate-like SnS2 gas sensors exhibited good gas selectivity for NO2 against SO2, CO, and NH3 at 25 °C. The response and recovery times are 540 and 1407 s for the flower-like SnS2 and 214 and 18 s for the plate-like SnS2, respectively. It is confirmed that a large specific surface area and the number of sulfur vacancies adversely affected the response and recovery times. Therefore, the plate-like gas sensor is expected to be a good candidate for NO2 gas-sensing applications at 27 °C.