Abundant active sites triggered by Co-doped SnS2 for ppb-level NO2 detection

Nitrogen dioxide (NO2) has serious negative effects on human health and atmospheric environment, thus necessitating the development of NO2 sensor for trace NO2 detection. The performance of gas sensor is closely related to active sites of sensing materials. Doping is an available strategy to modulate the number of active sites. Herein, Co-doped SnS2 nanomaterials were prepared by a facile one-step solvothermal method for NO2 sensing. The introduction of Co2+ inhibits the growth of SnS2 grain size and introduces S vacancy, which provides more active sites for NO2 adsorption. As a result, the sensor based on 10 wt% Co-doped SnS2 exhibits a response value of 169 % (S=(Rg-Ra)/Ra× 100 %) for 1 ppm NO2, high selectivity against other gases, appreciable moisture resistance, and low actual limit of detection (the response of 89.7 % to 1 ppb NO2) at 190 ℃. The remarkable sensing properties are mainly attributed to the abundant active sites and strong adsorption ability.