High performance acetone sensor based on γ-Fe₂O₃/Al-ZnO nanocomposites

Ternary nanocomposites made of γ-iron oxide and aluminum-doped zinc oxide (γ-Fe₂O₃/Al-ZnO NCs), with different metal oxides ratio (0%-100%) were prepared through a solvothermal sol-gel process. The synthesized materials were characterized by x-ray diffraction, UV-vis spectroscopy, photoluminescence (PL), scanning electron microscope and BET analysis. Characterization results demonstrated that the ternary γ-Fe₂O₃/Al-ZnO NCs are mainly constituted by γ-Fe₂O₃ and Al-ZnO individual phases, while structural and physical properties like surface area, pore size, optical band gap, PL and electrical conductivity were deeply affected by the composition of nanocomposite. The synthesized γ-Fe₂O₃/Al-ZnO NCs were employed to prepare conductometric gas sensors, then their sensing performances toward acetone were also investigated. Results revealed enhanced sensing performance of nanocomposites than both pure γ-Fe₂O₃ and Al-ZnO phases. In particular, the γ-Fe₂O₃(33%)/Al-ZnO based gas sensor showed the best sensing properties, like a high response of R _air/R _gas = 29, a short response time of 3 s, in addition to an improved selectivity toward acetone versus ethanol at an operating temperature of 200 °C. Overall, ternary γ-Fe₂O₃/Al-ZnO NCs appear to be promising for the development of conductometric acetone sensors.