Cr-doped NiO nanoparticles as selective and stable gas sensor for ppb-level detection of benzyl mercaptan

Abstract

Abstract High-performance, reproducible and stable gas sensors for aromatic compounds detection is important for the environmental monitoring and public health. In this work, we report a promising metal oxides semiconductor (MOS) gas sensor based on Cr-doped NiO nanoparticles (NPs) as the sensing materials for ppb-level detection of benzyl mercaptan. The prepared sensor with 25 at% Cr-doped NiO NPs showed the best performance with the gas response Rg/Ra value of 10.6 towards 100 ppb benzyl mercaptan. In addition, the sensor exhibited significantly high selectivity to benzyl mercaptan against typical interfering VOCs gases including aniline, benzene, trimethylbenzene, xylene, toluene, ethanol, acetone, carbon monoxide, ammonia and nitrogen dioxide. Moreover, the sensor showed remarkable stability after repetitive measurements for ten months. The superior performance of Cr-doped NiO NPs can be ascribed to the electron transfer among Ni-O-Cr bond, defective oxygen and chemical adsorption oxygen after Cr doping, which are beneficial for the gas adsorption and reaction on the surface of the sensing materials.