Green Sonochemical Synthesis of rGO Nanosheets‐Decorated by SnO2 Nanoparticles for Nitrogen Gas‐Sensing Applications

In recent years, the development of efficient and environmentally friendly synthesis methods for nanomaterials has gained significant attention in various research fields, particularly in gas‐sensing applications. Among these methods, ultrasonic synthesis stands out for its simplicity, cost‐effectiveness, and ecofriendly nature. Herein, a simple and green ultrasonic synthesis process is used to synthesize the SnO2 nanoparticles‐decorated rGO nanosheets. The obtained X‐ray diffraction reveals the tetragonal rutile‐type crystal structure. The transmission electron microscopy images reveal the decoration of SnO2 nanoparticles on the surfaces of the rGO sheets. SnO2 nanoparticles of size 4–8 nm are identified on the surfaces of the rGO sheets. Furthermore, the optical absorbance and photoluminescence spectra of the nanocomposites validate charge migrations occurring at the interface of SnO2 and the rGO sheets. Compared to the pristine SnO2 nanoparticles, the green ultrasonically synthesized SnO2 nanoparticles‐decorated SnO2/rGO nanocomposite exhibits better sensing performance against NO2 gas and shows selectivity for NO2 gas at 200 °C. The SnO2/rGO nanocomposite demonstrates high NO2 sensing with appealing sensing properties such as excellent responsiveness (67% at 400 °C), rapid reaction time (18 s), and short recovery time (25 s).