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 SnO 2 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 SnO 2 nanoparticles on the surfaces of the rGO sheets. SnO 2 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 SnO 2 and the rGO sheets. Compared to the pristine SnO 2 nanoparticles, the green ultrasonically synthesized SnO 2 nanoparticles‐decorated SnO 2 /rGO nanocomposite exhibits better sensing performance against NO 2 gas and shows selectivity for NO 2 gas at 200 °C. The SnO 2 /rGO nanocomposite demonstrates high NO 2 sensing with appealing sensing properties such as excellent responsiveness (67% at 400 °C), rapid reaction time (18 s), and short recovery time (25 s).