High efficiency toluene sensor based on iron-doped nickel oxide triple-shell microspheres with high moisture resistance

This paper provides a simple one-step synthesis of Fe-doped NiO triple-shell layer microsphere structures for toluene gas detection. The 2 at% Fe-doped NiO sensor has excellent sensing ability for toluene gas, with high response (36–100 ppm), low detection limits (100 ppb), fast response and recovery time (2/20 s). Moreover, the sensor demonstrates excellent moisture resistance, with satisfactory response to toluene even in conditions of 99 % relative humidity (34.1–100 ppm). To further investigate the adsorption properties of the sensor, a density functional theory (DFT) approach was employed, and the sensing mechanism of the NiO sensor was discussed detailly. Analysis of the results suggests that Fe-doped NiO triple-shell layer microspheres represent a promising approach for the design of high-performance toluene gas sensors.