MOF-derived porous In2O3 nanospheres sensitized by CdS quantum dots: A ppb-level NO2 sensor with ultra-high response at room-temperature

NO 2 is one of the most important atmosphere pollutants, causing great harm to the human body at very low concentrations (ppb levels). Herein, a novel fabrication idea for gas sensing materials was reported to detect ppb-level NO 2 via MOF-derived porous In 2 O 3 nanospheres (NSs) sensitized by CdS quantum dots (QDs). The good distribution of CdS QDs (2.5–4.0 nm) on porous In 2 O 3 NSs was verified by the transmission electron microscopy and element mapping analyses. In comparison to In 2 O 3 NSs, the CdS@In 2 O 3 composite nanospheres (CNSs) exhibited exceptional responses to ppb-level concentrations of NO 2 ( S =425.1@100 ppb) at room temperature (RT, 25 °C), 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 NO 2 and active O 2 – by well-dispersed CdS QDs. This work emphasizes that the MOF-derived In 2 O 3 porous NSs sensitized by CdS QDs can accurately detect ppb-level concentrations of the NO 2 at RT.