Enhanced performance of γ-Fe2O3:WO3 nanocomposite towards selective acetone vapor detection

Metal oxide nanocomposite sensors based on γ-Fe2O3 and WO3 were investigated in acetone vapor of various concentrations (1-100 ppm) at operating temperatures between 250 and 350 °C. The composites were prepared by simple solid state mixing and porous thick-film gas sensors were fabricated on alumina substrates. The γ-Fe2O3:WO3 (50:50) nanocomposite showed a marked enhancement in sensing response down to 1 ppm acetone vapor detection at 300 °C. The response was ~2-fold better compared to pure WO3 or pure γ-Fe2O3 with a very fast response (1 s) and very short recovery time (3 s). No appreciable sensitivity was observed towards alcohol vapor (an interfacing agent for diabetics) and in moisture (present in breath). The enhanced performance was due to n-n heterojunction effect.