Synthesis of SnS2/SnO2 nano-heterojunctions with increased reactive sites and charge transfer for ultrasensitive NH3 detection

In this work, the hydrothermally synthesized SnS2 nanosheets were calcined to form SnO2 nanoparticle decorated SnS2 nanosheets. The formed "raisin cake" SnS2/SnO2 complex increases the specific surface area and provides more contact area for gas molecule adsorption. The SnS2/SnO2 nanocomposite has a high sensing response to 50 ppm NH3 (392) and an excellent response/recovery time (6/8 s) to 50 ppm at room temperature. Therefore, SnS2/SnO2 nanocomposite has excellent repeatability, excellent NH3 gas selectivity, and humidity stability. And it is discussed that the reason for the enhanced NH3 sensing mechanism is the synergistic effect of SnS2/SnO2 structures. The existence of heterojunction was proved by XPS. These results demonstrate that the sensing material can effectively detect NH3 gas.