MOF-derived In2O3 nanotubes modified by Bi2Se3 for enhanced NOx detection at room temperature

The In2O3/Bi2Se3 composite was synthesized by loading Bi2Se3 flakes on MOF-derived In2O3 tubes through solvothermal method. The chemical composition, morphology and chemical state of elements for composite were examined through XRD, SEM, TEM and XPS. The In2O3/Bi2Se3 composite exhibited significantly enhanced sensing performance compared to pure In2O3 and Bi2Se3. The response value of In2O3/Bi2Se3 composite is 844 for 30 ppm NOx at 25 °C, which is 21 times that of pure In2O3, and it also displays shorter response /recovery time and lower detection limit. The remarkable gas-sensing properties of In2O3/Bi2Se3 composite are attributable to its large specific surface area, rapid electron mobility, abundant oxygen vacancies and the presence of n-n heterostructure. The adsorption behavior of NOx gas on the surface of In2O3/Bi2Se3 was explored using the in-situ diffuse reflectance infrared Fourier transform (DRIFT) spectrum. [Display omitted] •MOF-derived In2O3/Bi2Se3 composite was prepared by solvothermal method.•The response of In2O3/Bi2Se3 to 30 ppm NOx exhibits 21 times higher than pure In2O3.•The n-n heterojunction was formed between In2O3 nanobutes and Bi2Se3 flakes.•The mechanism of NOx adsorption was explored using in-situ DRIFT spectroscopy.