A high-performance gas sensor for the detection of H2S based on Nd2O3-doped ZnO nanoparticles

Pure ZnO and Nd2O3-doped ZnO nanoparticles were synthesized by a hydrothermal method. The crystal microstructure morphology and the surface physico-chemical state were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), respec-tively. The results show that the doping of the trace element Nd promotes the growth of short columnar ZnO crystal and causes a variety of structural defects due to the large radius difference. In addition, the substitution of Nd3+ with Zn2+ results in a large amount of oxygen vacancies, which effectively promotes the adsorption process of oxygen molecule. The gas sensing performances have been tested and the results indicate that 0.5% Nd2O3- doped ZnO exhibits more excellent sensitivity to H2S than that of pure ZnO, with a response up to 242-10 ppm H2S at the optimum temperature of 150 degrees C and excellent selectivity and repeatability as well. Meanwhile, the lowest detection limit of the 0.5% Nd2O3-doped ZnO sensor is 50 ppb.