Oxygen vacancy-mediated metal-organic gel-derived α-Fe2O3 for anomalous acetone sensing behavior

Abstract

The development of acetone gas sensors with high sensitivity, low detection limits and scalability holds significant importance for industrial production safety and disease diagnosis. Herein, oxygen vacancies-enriched α-Fe2O3 nanoparticles (M-Fe2O3 NPs) were synthesized through a novel metal-organic gel template strategy. Gas sensing experiments revealed that the prepared M-Fe2O3 sensor displayed unique p-type semiconductor behavior, distinct from the n-type commercial α-Fe2O3 (C-Fe2O3) sensor. Moreover, the sensor demonstrated excellent acetone sensing performance, including high response (2.6 @ 20 ppm), low detection limit (0.5 ppm), remarkable repeatability and selectivity, even under 80% relative humidity (RH), displaying impressive response and recovery properties. The enhanced p-type sensing properties of the M-Fe2O3 sensor were attributed to oxygen vacancies facilitating inversion (hole) layer formation and accelerating chemical reactions on the sensing materials surface, as evidenced by gas sensing performance data and O2-TPD characterization. Finally, the feasibility of preliminary diabetes diagnosis was demonstrated by detecting acetone levels in human exhaled breath. This work not only presents a straightforward approach for designing oxygen vacancies-enriched metal oxides but also has potential applications in constructing high-performance acetone sensing systems for diabetes diagnosis.