Effective hydrogen gas sensor based on NiO@rGO nanocomposite

A NiO@rGO nanocomposite is prepared by a freeze-drying method combined with heat treatment. The morphology and structure are analyzed through X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectra, and X-ray photoelectron spectroscopy. The results clearly show that NiO nanoparticles are uniformly anchored on the surface of the rGO nanosheet. The gas-sensing performance of the nanocomposite is also investigated to detect hydrogen. The NiO@rGO sensor exhibits good gas-sensing performance with high sensitivity, fast response, good reversibility, and selectivity toward hydrogen. The relative response of the sensor to 1% hydrogen is 0.64, the response time is 28 s, and the recovery time is 142 s. The improved sensing performance is due to the effective electron transfer between the NiO nanoparticles and rGO nanosheet.