Enhanced Sensing of Acetone by Al-ZnO Synthesized using Microwave-Assisted Combustion

Abstract

Detection of high-concentration acetone at low operating temperatures is crucial for the safety in industry. In this study, we have reported 242% acetone (500ppm) sensing by 5% Al-ZnO sample at 60oC and documented the synthesis of parent ZnO and its composites with ZnAl2O4 containing different Al content, namely 2%, 5%, and 10% Al-ZnO by microwave-assisted combustion method (fast exothermic redox reaction between Zinc nitrate and Aluminium Nitrates). XRD analysis with rietveld refinement confirmed the coexistence of ZnO and ZnAl2O4 phases, whereas UV-Vis and SEM analysis revealed optical and morphological changes. Gas sensing studies showed remarkable enhancement in acetone sensing by 5% Al-ZnO in compare to methanol, ethanol, isopropanol and benzene. The 5% Al-ZnO sample exhibited highest sensing of ~242% at 500 ppm with response and recovery time of ~272/~48s. The superior performance of 5% Al-ZnO can be attributed to the synergistic effect of the ZnAl2O4 phase which allows efficient charge transfer and enhances adsorption-desorption kinetics even at high concentrations. Overall, microwave-assisted combustion method appears to be an efficient and effective method for producing Al-ZnO with excellent acetone sensitivity and selectivity over a wide range of concentrations at low temperatures.