Indium Oxide Decorated WS2 Microflakes for Selective Ammonia Sensors at Room Temperature

Tungsten sulfide decorated with indium oxide nanoparticles (In2O3/WS2) was studied for a chemiresistive-type NH3 sensor at room temperature. It was found that the responses of the developed In2O3/WS2 heterostructure nanocomposite-based sensors are significantly improved to 3.81 from 1.45 for WS2. The response and recovery time of the heterostructure-based sensor was found to significantly decrease to 88 s/116 s (10 ppm) from 112 s/192 s for the WS2-based one. The sensor also exhibits excellent selectivity and signal reproducibility. In comparison to WS2 decorated with both ZnO and SnO2 in similar ways, the In2O3-decorated WS2 has overall better sensing performance in terms of sensitivity, selectivity and response/recovery speeds for NH3 from 1 ppm to 10 ppm at room temperature. The improved sensing properties of WS2 incorporating In2O3 could be attributed to the joint enhancement mechanisms of the “electronic and catalytic” sensitizations.