Room-Temperature acetone gas sensing properties of graphene oxide/zinc oxide nanocomposites synthesized by sol-gel method

The pristine zinc oxide (ZnO) and graphene oxide (GO)-based GO/ZnO nanocomposites were chemically prepared by low-cost and facile sol-gel route for room-temperature acetone gas sensors. Nanocomposites were synthesized according to different weight percentages (2, 4, 6 wt%) of GO. Structural analysis revealed that increasing wt% of GO does not affect the crystal structure of ZnO as the wurtzite phase was maintained in all the GO/ZnO nanocomposites. Field emission scanning electron microscope (FESEM) study shows the formation of hexagonal plate-like structure with an average thickness of 29.5 and 18.83 nm for pristine ZnO and GO/ZnO nanocomposite with 2 wt%, respectively. Raman spectroscopy confirmed all the fundamental bands of ZnO with D, G and 2D bands of GO in the GO/ZnO nanocomposites. Fourier transform infrared spectroscopy (FTIR) confirmed that C=O, Zn-O, and C-O chemical bonds were present in the samples. The photoluminescence measurements show a decrease in intensity with an increase in wt% of GO. Brunauer-Emmett-Teller (BET) measurements indicate an increase in surface area with an increase in wt% of GO. The pristine ZnO shows a maximum sensing response of 15.28% and the lowest response time of 180 s at 200 ppm of acetone. At 200 ppm concentration of acetone, the nanocomposite having 6 wt% of GO showed a maximum sensing response of 41.02% with a response time as low as 70 s. Thus, the synergistic effects of ZnO nanoparticles and GO lead to excellent sensing response of the nanocomposites.