A facile microwave synthesis of rGO, ZrO₂ and rGO–ZrO₂ nanocomposite and their room temperature gas sensing properties

Microwave irradiation technique provides a simple and quick synthesis route for nanomaterials at controlled experimental conditions. In this view, nanostructures of rGO, ZrO₂, and rGO–ZrO₂ composite were synthesized using microwave synthesis technique. Herein, we experimented the preparation of rGO using optimized conditions using convection mode at 373 K in a commercial microwave oven. Structural properties revealed the formation of mixed phases of the orthorhombic and rhombohedral crystal structure of ZrO₂. The preferential plane orientation was found to be in c-axis (002) for rGO–ZrO₂ nanocomposite, which revealed the predominance of rGO in the nanocomposite. Morphology of the prepared nanostructures exhibited agglomerated sheets, denser nanograins and randomly aggregated nanosheets for rGO, ZrO₂, and mixed nanocomposite respectively. Room temperature gas sensing properties of the prepared nanostructures were investigated and reported. rGO showed responses of 5.3 and 5.2 towards 200 ppm of trimethylamine (TMA) and methanol. ZrO₂ nanostructure showed a response of 35 towards 200 ppm of ammonia with response–recovery times of 91 and 6 s.