Perovskite hexagonal YMnO3 nanopowder as p-type semiconductor gas sensor for H2S detection

In this study, a H2S gas sensing element, hexagonal YMnO3 nanopowder, was prepared using a novel citrate method followed by calcination at different temperatures. Structural and microstructural characterizations were carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. XRD studies confirmed the formation of YMnO3 with a perovskite phase. The electrical properties were studied using impedance analysis; the results indicated that the conductivity depends on temperature. The presence of functional groups was determined using Fourier transform infrared spectroscopy (FT-IR). Thermal stability was determined by thermogravimetric analysis (TG/DTA). Moreover, the pore size distribution measurements and scanning electron microscopy (SEM) images of the perovskite YMnO3 reveal the mesoporous characteristics of the material. Hexagonal YMnO3 nanopowder annealed at 700 degrees C was used in a chemoresistive gas sensing device. The response, selectivity, and sensitivity of the sensing material were measured by changing the electrical resistance of the material. The results demonstrated that the hexagonal YMnO3 nanopowder exhibited good sensing performance for hydrogen sulfide gas (H2S) with a rapid response and high sensitivity at 100 degrees C for 20 ppm. The cross sensitivity was also checked for reducing gases such as CO, H-2, and LPG. The sensing mechanism of the YMnO3 sensor to H2S is also discussed. (C) 2015 Published by Elsevier B.V.