The detection of 4-methyl-1-hexene vapour at room temperature using a nickel oxide nanostructured based solid-state sensor

Semiconductor metal oxides such as nickel oxide (NiO), zinc oxide (ZnO), and tin dioxide (SnO₂) are the commonly used sensing materials in the fabrication of solid-state gas sensors, which are promising devices to detect volatile organic compounds. However, the growth of the real-life application of these sensors is poor because their high operational temperature, and poor selectivity towards the gas of interest. In this work, NiO nanoparticles, carbon nanoparticles (soot), and cellulose acetate are the sensing materials used to fabricate six sensors that were operated at room temperature for the detection of 4-methyl-1-hexene, 3-pentanone, octanol, tridecane, 2-decanone, and chloroform vapours. The prepared sensing materials were characterised using transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis. The introduction of cellulose acetate into NiO nanoparticles-carbon soot composite improved the sensitivity to the detection of volatile organic compounds. The mass amounts of NiO nanoparticles in (1:3 mass ratio) carbon soot-cellulose acetate composite were varied to study the sensitivity and selectivity of the volatile organic compounds. NiO nanoparticles-carbon soot-cellulose acetate composite with a mass ratio 1:1:3, was found to be more sensitive to 4-methyl-1-hexene vapour than 3-pentanone, octanal, 2-decanone, chloroform, and tridecane vapours. And the (1:1:3 mass ratio) ternary composite sensor was found to have a response time of 152 s, a recovery time of 95 s, and a limit of detection of 82 ppb. The sensor showed good reproducibility in detecting 26.6 ppm of 4-methyl-1-hexene vapour. The effect of humidity on the detection of 4-methyl-1-hexene vapour at room temperature was studied.