CuCrO2/Cr2O3 heterojunction gas sensor for low-temperature and high response H2S detection and its application for meat freshness evaluation.

Hydrogen sulfide (H2S) is a highly toxic and flammable gas that is also an important indicator of meat spoilage. Therefore, real-time and accurate detection of H2S concentration is essential to ensure environmental safety and human health. Despite its significance, achieving highly sensitive detection of H2S gases at low temperatures remains a formidable challenge. In this study, we used the biomass template method to controllably prepare CuCrO2-doped Cr2O3 p-p heterojunction hollow tubes. Among them, the 10.93 wt% Cu-doped Cr2O3 sensing material (Cu-Cr2O3-3) obtained by calcination at 500 °C has a good overall gas-sensing performance to H2S gas. It has a response value of up to 441.2 for 100 ppm H2S gas at 92 °C, as well as good selectivity, low calculated detection limit of 11.15 ppb and humidity resistance. Meanwhile, the reasons for the performance differences between the 5 composites were explored in detail by using various characterisation methods. The gas sensing mechanism of the Cu-Cr2O3-3 sensor was also analysed by combining MS, XPS and 'quasi-in-situ' Raman spectrum. In addition, we carried out experiments on the freshness detection of pork and shrimp by the Cu-Cr2O3-3 sensor, confirming its potential application in meat freshness evaluation.