Synthesis of α-Fe2O3/SiO2 nanocomposites for the enhancement of acetone sensing performance

Herein, a novel gas-sensing nanocomposite of α-Fe₂O₃/x%SiO₂ (x = 0, 10, 15, 20, 30) was synthesized for the first time by sol-gel. With an increase in SiO₂ concentration to 30 %, the average crystallite size and pore-size distribution of samples exhibited a decreasing trend. The surface area also showed an increasing trend with the introduction of SiO₂. Gas-sensing measurement results revealed that the α-Fe₂O₃/20 %SiO₂ nanocomposite showed the highest response (R_a/R_g = 50.20) to 500 ppm acetone at its optimal operating temperature of 290 °C, which was about 34 times higher than that of the pure α-Fe₂O₃ gas sensor. The response/recovery time of the α-Fe₂O₃/20 %SiO₂-based sensor to 500 ppm acetone was 14 s/7 s. The response/recovery time of α-Fe₂O₃ was 25 s/21 s. After SiO₂ was modified, the response/recovery speed increased. The results demonstrated the potential of α-Fe₂O₃/20 %SiO₂-based gas sensors for sensitive and selective detection of acetone.