Abstract

Reduced graphene oxide (RGO)-based NO₂ 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-temperatureNO₂ 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 NO₂ sensors, where SnO₂ nanoparticles modified nitrogen-doped RGO (SnO₂/N-RGO) hybrids had been used as sensing materials. The SnO₂/N-RGO hybrids were prepared by hydrothermal synthesis method using SnCl₄, 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 N₂ sorption isotherm were used to characterize the materials thus obtained, indicating the successful preparation of SnO₂/N-RGO hybrids. During the hydrothermal progress, SnCl₄ conversed into SnO₂ nanoparticles (NPs), and GO was reduced into RGO, while urea was decomposed into nitrogen-containing molecule and doped into RGO. It is found that SnO₂ NPs with the size of 3?C5 nm are uniformly dispersed on N-RGO nanosheets. Most importantly, SnO₂/N-RGO hybrids-based sensor exhibits superior sensing performances toward NO₂ operated at room temperature, which are better than those of pure RGO and SnO₂/RGO hybrids. For example, SnO₂/N-RGO hybrids show response of 1.38 to 5 ppm NO₂ 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 SnO₂ NPs. This novel sensor based on SnO₂/N-RGO hybrids promises to provide an essential sensing platform for the detection of NO₂ with excellent sensing performances at room temperature.