Abstract:
Several binary sulfides are used for sensing of gases such as NH3, NO2, and H-2, but not for H2S, especially at room temperature, because of the relative inactivity of metal sulfide surface bonds for this gas. The situation can be entirely different in the ternary case, however, due to the possible synergy of interactions involving dual cation surface chemistry. This is borne out by the present work wherein the Cu3SnS4 material, the Cu-rich ternary sulfide used for the first time in the gas sensing context, not only senses H2S at room temperature but also remarkably does so with high selectivity and stability. Thus, a combined experimental and computer modeling study on the use of nanocrystalline orthorhombic Cu3SnS4 phase is reported for H2S sensing. The material shows sensitivity for a wide range of H2S concentrations (from 10 to 2000 ppm). The performance of the sensing device fabricated on Kapton substrate remains intact even after several days and multiple bending cycles. Importantly, these experimental findings are consistent with the results of density functional theory calculations for binding energies for different gases, namely, H2S, NO2, NH3, and CO, on Cu3SnS4 surface.