An n-n type Y₂O₃-In₂O₃ interfacial structure for highly selective cataluminescence sensing of hydrogen sulfide

Hydrogen sulfide (H₂S) is a highly toxic gas that requires rapid and selective monitoring in chemically complex workplace atmospheres. In this work, Y₂O₃, In₂O₃, and Y₂O₃-In₂O₃ nanomaterials were synthesized by a solvothermal method followed by calcination, and their cataluminescence (CTL) sensing behaviors toward H₂S were systematically investigated. Structural characterization by XRD, XPS, TEM, HRTEM, and elemental mapping confirmed the successful formation of the Y₂O₃-In₂O₃ composite with intimate interfacial contact between the two oxide phases. Compared with the two single oxides, the Y₂O₃-In₂O₃ composite exhibited a markedly enhanced CTL response toward H₂S while maintaining excellent selectivity against other interfering gases. Under the optimized conditions, the sensor showed a linear response to H₂S in the range of 10-400 ppm, and the limit of detection was estimated to be 6 ppm at a signal-to-noise ratio of 3. The sensor also displayed a response time of 3 s, a recovery time of about 10 s, good repeatability with an RSD of 3.6%, and satisfactory stability over 30 days with an RSD of 5.8%. Recovery experiments in simulated and real-world air samples gave values of 93.8%-101.5%, indicating strong anti-interference capability. GC-MS identified SO₂ as the oxidation product, and density functional theory calculations revealed that the Y₂O₃-In₂O₃ interfacial structure provided the strongest H₂S adsorption and activation among the three models. These results demonstrate that Y₂O₃-In₂O₃ is a promising CTL sensing material for selective H₂S detection.