Humidity-activated H2S sensor based on SnSe2/WO3 composite for evaluating the spoilage of eggs at room temperature

Hydrogen sulfide (H2S), as a representative food spoilage gas produced by the breakdown of sulfur-containing proteins, is highly irritant and toxic. Designing gas sensors sensitive to H2S for food spoilage evaluation is of great significance for automated quality control in the modern food industry. However, humidity in the environment can generally deteriorate the detection performance of conventional metal oxide semiconductor gas sensors. Therefore, it is critical to develop H2S sensors based on novel materials that can operate effectively in atmospheric humidity conditions. In this work, tin diselenide (SnSe2) nanosheets decorated with tungsten trioxide (WO3) nanoparticles are synthesized by a one-step ultrasound strategy, and used as sensing layers for H2S gas sensors. The water molecule activated charge-transfer of the SnSe2/WO3 composite boosts H2S sensing ability at high relative humidity (RH) levels. At room temperature (25 °C), the SnSe2/WO3 composite sensor with optimal mass ratio exhibits enhanced H2S response value (33.80%@10 ppm) compared with that of the pristine SnSe2 sensor (14.29%@10 ppm) at 82% RH. In addition, the fabricated sensor is proven to be practically effective for evaluating the spoilage of eggs by comparing the sensing response of a fresh egg with that of a spoiled egg. This study offers possibilities for evaluating the spoilage of foods in poultry, aquatic, and food processing industries using a rapid and sensitive humidity-activated H2S gas sensor.