Highly sensitive Pt-functionalized In2O3/SnS2 nanoflowers to realize the rapid detection of H2S gas

Abstract

Recently, SnS2 sensing material has received lots of attention in the application of gas detection owing to its merits of high physical affinity and appropriate bandgap width. Nevertheless, the gas sensors based on SnS2 sensing materials are subjected to the shortcomings of poor selectivity and long response/recovery induced by the low conductivity of SnS2 material. This article employs a secondary solvothermal method to prepare flower-like In2O3/SnS2 heterostructures modified by noble metal Pt nanoparticles to realize the rapid detection of H2S for the first time. The gas-sensing tests indicate that this heterostructure greatly improves the pure SnS2 material’s conductivity and enhances the adsorption capacity for H2S gas molecules. Compared with pure SnS2 and In2O3/SnS2 sensors, the Pt-In2O3/SnS2 sensor presents superior repeatability during multiple measurement cycles and excellent selectivity towards H2S at the optimum operating temperature of 220 ℃. The sensor also exhibits a fast response/recovery of 10 s/506 s together with a large gas response of 11.98 toward 200 ppm H2S. The strengthened sensing characteristics are primarily attributed to the abundant active sites in the Pt-In2O3/SnS2 composites, the excellent carrier transfer ability caused by the In2O3/SnS2 heterojunction, the strong gas adsorption ability induced by noble metal platinum, and the modulated Schottky barrier. Our work provides an effective route for the improvement of the gas sensitivity of SnS2-based H2S gas sensors.