Phase boundary induced drastic sensing performance enhancement of mixed-phase N-Fe2O3 (α/γ) gas sensors for acetone

The development of high-performance, portable and miniaturized metal oxide semiconductor (MOS)-based chemiresistive materials is important for portable gas sensors. Phase boundaries provide lasting inspiration and a promising avenue for designing advanced functionalities using nanomaterials. However, the impact of different phase boundaries in a single MOS on the performance of MOS-based chemiresistive gas sensors has been rarely explored. Here, we report a mixed-phase N-Fe2O3 (α/γ) gas sensor with rich phase boundaries, which exhibits an enhancement of the response up to 386 towards 50 ppm of acetone at 240 °C. This is attributed to the generation of the internal electric field (IEF) and defects originating from lattice mismatch at the N-Fe2O3 (α) – N-Fe2O3 (γ) phase boundaries, which providing more active sites for adsorption of oxygen and acetone molecules. This work clearly shows that we can optimize the gas sensing catalyst of low-cost materials by regulating the phase boundaries of nanomaterials to develop high-precision portable gas sensors.