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.