Sensing of acetone by Al-doped ZnO

The development of chemoresistive gas sensors for environmental and industrial air monitoring as well as medical breath analysis is investigated. Flame-made ZnO nanoparticles (NPs) doped with 1 at% Aluminum exhibited higher sensing performance (response 245, response time ∼ 3 s, and sensitivity 23 ppm−1) than pure ZnO and those made by a hydrothermal method (HT) (56, ∼ 12 s, and 4 ppm−1) for detection of 10 ppm acetone. Furthermore, their sensing response of ∼10 to 0.1 ppm of acetone at 90% RH is superior to other metal oxide sensors and they feature good acetone selectivity to other compounds (including NH3, isoprene and CO). Characterization by N2 adsorption, X-ray photoelectron and UV–vis spectroscopies reveals that the improved sensing performance of flame-made Al-doped ZnO NPs is associated primarily to a higher density of oxygen vacancies than pure ZnO and all HT-made NPs. This leads to a greater number of adsorbed oxygen ions on the surfaces of Al-doped ZnO NPs, which can react with acetone molecules.