Hierarchical flower‐like NiFe ₂ O ₄ with core–shell structure for excellent toluene detection

Abstract

Abstract The extensive use of toluene stimulates the effective detection by sensitive gas sensors based on unique materials. Here, hierarchical flower‐like NiFe 2 O 4 with core–shell architecture was synthesized by a facile hydrothermal method in the presence of urea and NH 4 F. The controllable experiments indicated that the burr spheres and football‐like samples were produced with individual urea or NH 4 F. The flower‐like NiFe 2 O 4 sensor exhibited outstanding sensitivity of 19.95 to 100 × 10 −6 toluene with low detection limit (1 × 10 −6 ). Furthermore, the sensor showed superior sensing selectivity and long‐term stability to toluene. The excellent sensing properties could largely arise from a combination of high surface area, numerous active sites, porous structures, and the native catalytic characteristics of NiFe 2 O 4 to facilitate toluene molecules adsorption, diffusion, and reaction.