Preparation and Gas Sensing Properties of rGO/CuO Nanocomposites

Gas sensors are instrumental in the control and monitoring of air pollution. A facile fabrication method for low-cost gas sensors with high sensitivity and a fast response time is crucial in practical applications. Here, reduced graphene oxide (rGO)–CuO nanocomposites were synthesized for gas-sensing applications using a facile hydrothermal method. The crystal structure, surface morphology, and electrical properties of the nanocomposites were inferred from X-ray powder diffraction patterns, scanning electron microscopic images, and current–voltage ( I – V ) measurements, respectively. The results confirmed a high-quality rGO–CuO material with a spherical flower-like morphology. The CuO material showed a single-phase monoclinic crystal structure with an average crystal size of ∼21 nm. Within the composite, high-quality rGO was incorporated into the porous spherical flower-like CuO material. In gas-sensing measurements, the rGO–CuO nanocomposite detected NO 2 gas at low concentrations (1–5 ppm) with reasonably high response values and a fast response time (<1 min). An rGO–CuO nanocomposite-based sensor was fabricated, showing good repeatability for practical applications.