Construction of heterojunction based on Nd2S3 and tin dioxide for rapid detection of ethanol

The gas-sensing properties of Nd2S3 have not been previously explored. In this study, a novel composite material comprising rare-earth metal sulfide (Nd2S3) and metal oxide (SnO2) was successfully prepared using a two-step hydrothermal method for the rapid detection of ethanol. Characterization results revealed that the morphology and specific surface area of Nd2S3-SnO2 remained largely unchanged after composite formation. However, the built-in electric field established between Nd2S3 and SnO2 significantly enhanced carrier transport and separation. Additionally, the introduction of extra oxygen vacancies increased the content of chemisorbed oxygen, providing more active sites for ethanol molecules, thereby improving the gas-sensing performance. The Nd2S3-SnO2 sensor demonstrated extremely high detection accuracy (R2=0.9965) over the 20–300 ppm ethanol concentration range, with response/recovery time of 8/274 s at 100 ppm ethanol concentration and response value of 93. It also possesses excellent selectivity to ethanol, long-term stability and reversibility. This work represents a preliminary exploration of the gas-sensing properties of Nd2S3 and its underlying mechanisms through the construction of a heterojunction structure between metal sulfide and metal oxide. •The basic gas-sensitive properties and mechanism of Nd2S3 were investigated.•It has a fast response time of 8 s and a high response of 93–100 ppm ethanol.•The heterojunction of Nd2S3 and tin dioxide was constructed for the first time.