Preparation of Ag nanoparticles-SnO2 nanoparticles-reduced graphene oxide hybrids and their application for detection of NO2 at room temperature

Abstract

A novel NO2 gas sensor has been constructed using Ag nanoparticles-SnO2 nanoparticles-reduced graphene oxide (AgNPs-SnO2-rGO) hybrids as sensing materials. AgNPs-SnO2-rGO hybrids were prepared by a two-step wet-chemical method. Firstly, SnO2-rGO hybrids were synthesized by hydrothermal treatment of aqueous dispersion of GO in the presence of SnCl4. Then, AgNPs-SnO2-rGO hybrids were obtained by in situ reduction of AgNO3 on the surface of SnO2-rGO hybrids. The combined characterizations of UV–vis spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectrometer (EDX), elemental mapping, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and Raman spectra were used to investigate the structure of AgNPs-SnO2-rGO hybrids. Most importantly, the sensor based on AgNPs-SnO2-rGO hybrids exhibits good sensing performance for NO2 sensing operating at room temperature. For example, the response time and recovery time of the sensor based on AgNPs-SnO2-rGO hybrids for 5ppm NO2 are 49s and 339s, which are much shorter than that of SnO2-rGO hybrids (415s and 740s), indicating that the sensing performances for NO2 sensing at room temperature have been tremendously enhanced by introduction of AgNPs into SnO2-rGO hybrids.