Realizing Synergy between In2O3 Nanocubes and Nitrogen-Doped Reduced Graphene Oxide: An Excellent Nanocomposite for the Selective and Sensitive Detection of CO at Ambient Temperatures

Hierarchical mesoporous In2O3 nanocubes and nitrogen-doped reduced graphene oxide indium oxide nano cube (In-NrGO)composites were prepared for carbon monoxide (CO) sensing. The as-synthesized materials were systematically investigated by different characterization techniques such as field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetic analysis, X-ray photoelectron spectroscopy, micro-Raman, Fourier transform infrared spectroscopy, and photoluminesce analysis. The obtained results are consistent with each other. The CO-sensing characteristics of the In2O3 nanocubes and in(NrGo) composites were examined at different operating temperatures (35 degrees C < T-s, < 300 degrees C) and CO concentrations (1-1000 ppm). Owing to their large surface-to-volume ratio and porosity, the In2O3 nanocubes exhibited a superior sensitivity with a detection limit of 1 ppm at 250 degrees C. Furthermore, to enhance the sensing characteristics and reduce the operating temperature, a composite of NrGO and In2O3 nanocubes was fabricated. The incorporation of NrGO drastically improved the sensing performance of the In2O3 nano cubes, showing an excellent sensitivity (S-R similar to 3.6-5 ppm of CO at similar to 35 degrees C) with appreciably fast response (Gamma(REs) similar to 22 s) and recovery(Gamma(REC) similar to 32 s) times. The sensing studies supported by the structural and morphological material characteristics lead to the plausible sensing mechanism proposed.