Enhanced acetone sensing performance of Ti3C2 MXene/α-Fe2O3 nanorod composite

An optimized acetone gas sensor based on Ti3C2/alpha-Fe2O3 (TF) composite materials was synthesized using microwave and etching methods. The structures, morphology and composition of the TF composites were characterized via XRD, XPS, SEM and TEM. The crystal of alpha-Fe2O3 porous nanorods is hexagonal, and the alpha-Fe2O3 nanoclusters formed from alpha-Fe2O3 nanorods were adhered adequately on the lamellar Ti3C2 MXene in the TF composite. The specific surface area and surface defects of the TF composites increased compared with pure alpha-Fe2O3 nanocluster material, thus exposing a large number of gas adsorption sites. Furthermore, the excellent electrical conductivity and high free charges transfer ability of Ti3C2 MXene provided more electrons for the gas-sensitive reaction and enhanced the transmission capacity of gas-sensitive reaction electrical signal, respectively. The Schottky barriers were formed at the interface of alpha-Fe2O3 and Ti3C2 MXene increasing the resistance of TF gas sensor in air, which is beneficial to the response of TF gas sensor. So, the gas-sensitive performance of TF gas sensor to acetone was greatly improved. The response of TF gas sensor to 100 ppm acetone was up to 23.38, which was nearly 2.3 times higher than pure alpha-Fe2O3 gas sensor. The lower detection limit of TF gas sensor could be as low as 1 ppm. In addition, the TF gas sensor had excellent selectivity, long-term repeatability and stability for acetone.