High-performance reduced graphene oxide-based room-temperature NO2 sensors: A combined surface modification of SnO2 nanoparticles and nitrogen doping approach

Reduced graphene oxide (RGO)-based NO 2 sensors have attracted considerable attention due to their excellent advantages of low power consumption and manufacturability to facilitate massive deployment. However, it is still a great challenge to fabricate RGO-based room-temperatureNO 2 sensors with excellent sensing performances. Herein, we have demonstrated a combined surface modification and heteroatom doping approach to enhance the sensing performances of RGO-based room-temperature NO 2 sensors, where SnO 2 nanoparticles modified nitrogen-doped RGO (SnO 2 /N-RGO) hybrids had been used as sensing materials. The SnO 2 /N-RGO hybrids were prepared by hydrothermal synthesis method using SnCl 4 , GO and urea as precursors. The combined characterizations of X-ray diffraction (XRD), energy-dispersive X-ray spectrometer (EDS), elemental mapping, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), Raman spectra as well as N 2 sorption isotherm were used to characterize the materials thus obtained, indicating the successful preparation of SnO 2 /N-RGO hybrids. During the hydrothermal progress, SnCl 4 conversed into SnO 2 nanoparticles (NPs), and GO was reduced into RGO, while urea was decomposed into nitrogen-containing molecule and doped into RGO. It is found that SnO 2 NPs with the size of 3–5   nm are uniformly dispersed on N-RGO nanosheets. Most importantly, SnO 2 /N-RGO hybrids-based sensor exhibits superior sensing performances toward NO 2 operated at room temperature, which are better than those of pure RGO and SnO 2 /RGO hybrids. For example, SnO 2 /N-RGO hybrids show response of 1.38 to 5   ppm NO 2 with the response time and recovery time of 45   s and 168   s. The excellent sensing performances are attributed to incorporation of N atoms into RGO and the modification of RGO with SnO 2 NPs. This novel sensor based on SnO 2 /N-RGO hybrids promises to provide an essential sensing platform for the detection of NO 2 with excellent sensing performances at room temperature.