Optimization and gas sensing properties of Au nanoparticle modified α-Fe 2 O 3 nanodisk structures for highly sensitive acetone detection

Au nanoparticle (Au NP) modified α-Fe 2 O 3 nanodisk structures are obtained using a facile hydrothermal method and annealing based surface treatment. XRD, EDS, SEM, TEM and XPS are used to characterize the as-prepared samples, showing crystalline structured Au NPs of about 6–16 nm in diameter on the surface of α-Fe 2 O 3 nanodisk structures of about 145 ± 15 nm in diameter. The Au NP modified α-Fe 2 O 3 nanodisk structures are then investigated for acetone detection under different operating temperatures, showing improved gas sensing performance compared to the pure α-Fe 2 O 3 nanomaterial. In particular, under the optimum working temperature (275 °C), the sensor response of Au 0.5 Fe can reach a sensibility of 19.5 toward 100 ppm acetone, which is about two times higher than that of the pure one. Meanwhile, the Au 0.5 Fe acetone sensor also exhibits fast response and recovery time (4 s/7 s), good linear relationship (50–5000 ppb), low detection limit (50 ppb), excellent long-term stability and superior selectivity. Finally, the enhanced gas sensing mechanism of Au NP modified α-Fe 2 O 3 nanomaterials can be attributed to the combined action of chemical and electronic sensitization of Au NPs, which are promising as highly sensing materials toward acetone detection.