MOFs-derived NiFe2O4 fusiformis with highly selective response to xylene

NiFe₂O₄ fusiformis was derived from Ni/Fe bimetal metal-organic frameworks (MOFs) precursors prepared using a facile hydrothermal method, and the corresponding morphology, microstructure, and gas sensing properties were investigated. After thermal treatment at 350 °C in air, the Ni/Fe MOFs ellipsoid were completely converted into NiFe₂O₄ fusiformis, leading to a big volume shrink because of the removing of organic ligands. The NiFe₂O₄ fusiformis was used to fabricate gas sensor to detect xylene operating at 300 °C. The sensor exhibited a good response sensitivity of 31.52 with response/recovery time of 50.10 s/40.30 s, respectively, toward 500 ppm xylene. It also showed a remarkably high selectivity to xylene against other gases such as toluene, ethanol, methanol, acetone, isopropanol, ammonia, formaldehyde, and benzene. The excellent performance could be ascribed to the nature and the unique morphology of as-prepared NiFe₂O₄ with high specific surface area (60.50 m²/g) and porous microstructure. These findings may render a new opportunity to fabricate gas sensor for xylene detection based on p-type NiFe₂O₄.