Fe2O3/Ti3C2Tx derived TiO2 hierarchical heterostructure for the detection of low-concentration H2S at room temperature

The development of high-performance room temperature gas sensors remains a great challenge. Herein, a novel three-dimensional (3D) Fe2O3 nanoflowers (NFs)/Ti3C2Tx derived TiO2 nanosheets (NSs) hierarchical heterostructure was prepared by hydrothermal treatment and chemical bath deposition (CBD) method. With the unique structure, two-dimensional (2D) Ti3C2Tx derived TiO2 NSs provide an ideal platform for the nucleation and growth of the Fe2O3 NFs. By controlling the CBD time, the growth evolution of Fe2O3 NFs onto Ti3C2Tx derived TiO2 NSs can be effectively regulated. At room temperature, the Fe2O3/Ti3C2Tx derived TiO2 sensor with optimal CBD time (45 min) exhibits the highest sensitivity of 48.6% for 10 ppm H2S, while both the Fe2O3 and Ti3C2Tx derived TiO2 sensors have nearly no response to 50 ppm H2S. Additionally, the Fe2O3/Ti3C2Tx derived TiO2 sensor displays the high selectivity to H2S, low limit of detection (200 ppb) and good repeatability. The constructing of 3D Fe2O3/Ti3C2Tx derived TiO2 hierarchical heterostructure opens a new route to develop other high-performance room temperature gas-sensing materials.