Electrospun NiO nanofibers with Rh decoration for enhanced acetone sensing performances

Abstract

Construction of high-performance gas sensors based on p-type metal oxides is still a big challenge. In this work, with the objective of improving the sensing properties of p-type NiO, a series of porous Rh–NiO heterojunction nanofibers with various molar ratios (Rh/Ni\u2009=\u20093%, 5% and 7%) are fabricated by a facile electrospinning technique. The effects of Rh content on surface area, oxygen species absorbing capability, as well as acetone sensing properties of NiO nanofibers are systematically investigated. Sensing results demonstrate that the Rh–NiO sensor with an optimal Rh amount of 5 mol% exhibits the highest p-type response of 70.10 to 200 ppm acetone at 225 °C, which is 37.9 times higher than that of pure NiO nanofiber sensor. Moreover, the 5 mol% Rh–NiO nanofibers also possess excellent acetone selectivity. The improved sensing response of Rh–NiO nanofibers is mainly attributed to the formation of ohmic contacts between Rh nanoparticles and NiO nanoparticles, facilitating the reduction of sensor resistance in air and the increase of chemisorbed oxygen capability. Chemical sensitization effect of Rh nanoparticles and increased BET surface area also contribute to the improved acetone response of Rh–NiO nanofibers.