Fabrication of Lettuce-Like ZnO Gas Sensor with Enhanced H2S Gas Sensitivity

In this work, a lettuce-like ZnO gas sensor with high sensitivity for H2S detection was successfully fabricated by a one-step hydrothermal method. Characterization analysis of the phases, crystallinities, morphology, and chemical compositions indicated that lettuce-like ZnO has a lettuce-like microsphere structure composed of wurtzite hexagonal ZnO sheets. A gas sensitivity test of the lettuce-like ZnO showed that the sensor had a high H2S response (113.04 for 100 ppm H2S) and H2S selectivity. The lettuce-like ZnO sensor has fast response characteristics while maintaining high sensitivity, and has a response time as low as 15 seconds and a recovery time of 90 seconds, and the detection limit reaches 1 ppm. The sensitive mechanism of lettuce-like ZnO sensor to H2S is also discussed.