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 (alpha/gamma) gas sensor with rich phase boundaries, which exhibits an enhancement of the response up to 386 towards 50 ppm of acetone at 240 degrees C. This is attributed to the generation of the internal electric field (IEF) and defects originating from lattice mismatch at the N-Fe2O3 (alpha) - N-Fe2O3 (gamma) 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.