SnO₂ Nanosheets for NIR-Enhanced NO₂ Sensing and Adsorption/Desorption

Very recently, metal–organic framework (MOF)-based derived oxides demonstrated excellent sensing performance to NO 2 . However, the study on the enhancement of gas-sensing characteristics by near-infrared (NIR) light for MOF-based derived oxides is still limited. In this work, we introduced the synthesis of MOF-derived SnO 2 nanosheets by solvothermal and annealing processes. The structural composition and microstructure of SnO 2 nanosheets were studied by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller. The derived SnO 2 nanosheet-based gas sensor has an extremely low theoretical detection limit to NO 2 (45 ppb), ultrahigh response (1500 to 100 ppm), outstanding stability, and ideal selectivity. Furthermore, NIR illumination shortens the SnO 2 sensor’s NO 2 adsorption/desorption process. Moreover, we also proposed that NIR-excited photoelectrons were instrumental in optimizing the NO 2 gas-sensing performance of SnO 2 sensors. Therefore, MOF-based SnO 2 sensors are attractive for high response and rapid detection of NO 2 at low operating temperatures and are expected to be widely used in the preparation of NIR-enhanced NO 2 gas monitoring sensors.