Pd, Ni, Cu and Ag modified SnS: A potential candidate for NH3 and NO2 detection and scavenging

NO2 and NH3 chronically pose serious concerns to the security of industrial production and human health, thus it is essential to accomplish real-time monitoring of harmful gases. In this work, employing density functional theory, four transition metal nano particles, Pd, Ni, Cu, and Ag are adopted to modify the surface of the SnS monolayer further exploring the adsorption mechanism and electrical properties of X-SnS (X = Pd, Ni, Cu, and Ag) for NO2 and NH3 gas molecules. Due to its highest binding energy (−3.793 eV), the results demonstrate that Ni-SnS has the most stable decorated structure. Depending on the degree of orbital hybridization, Pd, Ni, Cu, and Ag modified SnS monolayers have enhanced adsorption energy and electron transfer to varying degrees. Moreover, among four modified structures Ag-SnS exhibits the best adsorption performance. X-SnS (X = Pd, Ni, Cu and Ag) can be applied as a good NO2 adsorbent under both ambient and high temperature. In addition, Ni-SnS, Ag-SnS and Cu-SnS sensing systems have different desorption capacities at different operating temperatures, which will help to achieve differentiated gas sensing and gas selective sensing.