Tin dioxide nanoparticles with high sensitivity and selectivity for gas sensors at sub-ppm level of hydrogen gas detection

A wet chemical method was employed to prepare Au-loaded sensor using tin dioxide (SnO2) nanoparticles (NPs) which has excellent hydrogen (H-2) gas sensing properties. The structural, compositional, morphological, and electrochemical properties of these materials are characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy and electrochemical workstation, respectively. The results show that the response time of Au-loaded sensor based on SnO2 NPs to 100 ppm H-2 is 26 s at 350 degrees C, which is much shorter than that of the pristine SnO2 sensor. Meanwhile, the effect of operating temperature and Au loading on 'n' value (factor for evaluating sensitivity response) is studied and the results demonstrated that the Au-loaded sensor based on SnO2 NPs can detect H-2 gas down to 0.4 ppm. Moreover, the Au-loaded sensor based on SnO2 NPs with an excellent selectivity to H-2 gas against carbon monoxide, methane, and sulfur dioxide is illustrated in this paper, which indicates that the Au-loaded sensor using SnO2 NPs is a good candidate for practical H-2 sensors and other industrial applications. Statistical analysis was performed on the FESEM images of sensors based on SnO2 NPs and 0.5 atomic (at)% Au-loaded SnO2 NPs. Roughness parameters were evaluated and a correlation was established between the morphology, topography and chemical composition of the samples.