Ultrasensitive H2S Gas Sensor Based on SnO2 Nanoparticles Modified WO3 Nanocubes Heterojunction

This work presents an excellent H2S gas sensor based on tungsten oxide and tin dioxide (WO3/SnO2) nanocomposites. WO3 nanocubes and SnO2 nanoparticle materials were synthesized by hydrothermal method, and composite and single material sensors were prepared based on these two materials. The sensing performance of WO3/SnO2 composite nanomaterials to H2S gas was studied systematically. First, it is determined that the optimum working temperature of the composite material sensor is 200 °C, and the optimum mass ratio of WO3 and SnO2 is 1:1. The response and recovery time of the composite sensor to 2-ppm H2S gas are 25 and 41 s, respectively, and the response value is as high as 55.24%. The sensor has excellent repeatability and long-term stability. The sensor has specific selectivity for H2S gas. In addition, a H2S gas detection circuit is constructed to realize the real-time display of gas concentration and the alarm of exceeding the limit.