In this study, we demonstrate the multifunctional property of a nanocomposite (NC) synthesized by combining Ag-doped ZnO with graphene oxide (GO) nanosheets. The Ag-ZnO/GO NC works as an efficient photocatalyst to remove methylene blue (MB) dye (a common water pollutant) from water, and functions also as a good sensing material to detect relative humidity (RH) of air. X-ray diffraction confirmed hexagonal wurtzite crystal structure of ZnO whereas scanning and transmission electron microscopies revealed the successful integration of Ag-ZnO nanoparticles (NPs) onto GO sheets forming well-defined NC. The optimized Ag-ZnO/10%GO NC (AZO-10%GO NC) exhibited 98.95% degradation efficiency for MB dye under sunlight within just 40 min, a remarkably improved performance compared to only 82.99% degradation by pure ZnO NPs. Interestingly, the same Ag-ZnO/10%GO NC also exhibits a high sensing response of ~ 406 at 74% RH along with fast response and recovery times of 7 s and 21 s, respectively when tested as a chemi-resistive film to sense RH of air. Thus, this work demonstrates the utility of the Ag-ZnO/10%GO NC for both water and air quality monitoring as it can not only remove organic pollutants from water bodies but also can monitor RH of air.
Amrute et al. (Tue,) studied this question.