Mof-Derived Porous In2o3 Nanospheres Sensitized by CDS Quantum Dots: A Ppb-Level No2 Sensor with Ultra-High Response at Room-Temperature

With the growing focus on health concerns, there is an urgent need to develop gas sensors capable of detecting extremely low concentrations of NO2 at room temperature (RT) (25 ºC). Herein, MOF-derived porous In2O3 nanospheres (NSs) sensitized by CdS quantum dots (QDs) were fabricated using a simple solvothermal and drop coating method. The good distribution of CdS QDs (2.5–4.0 nm) on porous In2O3 NSs was verified by the transmission electron microscopy and element mapping analyses. In comparison to In2O3 NSs, the CdS@In2O3composite nanospheres (CNSs) exhibited exceptional responses to ppb-level concentrations of NO2 (S=425.1–100 ppb) at RT, while also demonstrating good selectivity and response reproducibility. These improvements in sensing performance were attributed to the synergies of the electronic effects of CdS QDs, MOF-derived porous nanostructures, and enhanced adsorption of NO2 and active O2- by well-dispersed CdS QDs. This work emphasizes that the MOF-derived In2O3 porous NSs sensitized by CdS QDs can accurately detect ppb-level concentrations of NO2 at RT.