Low-temperature NO2 gas sensor fabricated with NiO and reduced graphene oxide hybrid structure

•Low temperature operable and highly sensitive gas sensors were fabricated.•The rGO plays important roles in effective charge transfer from NiO.•The well-developed NiO flower structures on the rGO surface enhanced the sensitity.

The fabrication of highly sensitive gas sensors that can monitor environmental toxic gases, such as nitrogen dioxide (NO2), which is one the most harmful gases to human health, attracts considerable attention. In this study, a hybrid structure composed of reduced graphene oxide (rGO) and a p-type NiO hierarchical structure (NiO-rGO) is fabricated using a facile solution process. The morphology and surface properties are analyzed by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The NO2 sensitivity is enhanced by the high surface to volume ratio of the NiO hierarchical structures as well as the enhanced charge transfer of NiO to rGO. The fabricated sensor with a hierarchical NiO and rGO hybrid structure exhibiting high sensitivity and selectivity at a low temperature (100 °C) with a rapid response time.

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