Ammonia Sensing Properties of SnS₂/SnO₂ Nanocomposite-Based Gas Sensor by SnS₂ Annealing

Tin disulfide has been demonstrated effective for ammonia detection, while its potential application has been seriously limited by high working temperature and low sensitivity. In this article, SnS2/SnO2 nanocomposites are prepared through a two-step method. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis show that the material would be transformed from SnS2 to SnS2/SnO2 composites by increasing annealing temperature. Gas testing results have shown that SnS2/SnO2 nanocomposites exhibit high sensitivity and good stability to ammonia, and the response to 100-ppm ammonia at 80 °C can reach 5.91. The sensor response was relatively stable at the target gas concentration. The high response of SnS2/SnO2 composites to ammonia at low temperatures might be due to SnS2 surface defects and heterostructure. From the perspective of atom and energy, adsorption energy has been simulated and calculated by the first principle analysis, to some extent, which proved that SnS2/SnO2 nanocomposite can improve the response to ammonia gas.