Development of magnesium-doped zinc oxide nanopowders for conductometric acetone gas sensors

Abstract

This research investigates magnesium-doped zinc oxide nanoparticles (NPs) synthesised by a modified sol–gel technique to create a high-performance gas sensing device with an enhanced sensing layer. The synthesised nanoparticles' structural, morphological characteristics, composition, and optical properties were analysed using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDX), UV-Vis absorption, and photoluminescence spectroscopy (PL). XRD analysis depicts that the samples possessed a hexagonal crystal structure with high crystallinity. TEM and SEM analyses indicated that the nanoparticle size was approximately 45 nm, and this size increased with the increasing magnesium content. The gas sensor evaluations were performed in the temperature range from 200 to 400 °C. The ZnO sample that was doped with 1% Mg (M1ZO) demonstrated the greatest response (∼19.9) to 40 ppm acetone (C₃H₆O) at 300 °C. This sensor exhibited quicker response and recovery times, ranging from 2 to 332 s, respectively, alongside enhanced selectivity for C₃H₆O when compared to ammonia (NH₃), carbon dioxide (CO₂), hydrogen sulphide (H₂S), and sulphur dioxide (SO₂). These findings suggest that Mg-doped ZnO holds promise as a material for controlling pollution and for applications in environmental gas sensing.