Shape-controlled CoFe2O4 nanoparticles as an excellent material for humidity sensing

Abstract

The humidity sensing performance of cobalt ferrite nanoparticles (CoFe₂O₄ NPs) with controlled morphology obtained via a solution route is reported in this work. The humidity sensing properties of the presented CoFe₂O₄ NPs ferrite sensor were investigated by exposing it to a broad humidity range of 8–97% at room temperature. CoFe₂O₄ NPs with spherical, cubic, and hexagonal shapes have been successfully achieved by tuning the growth conditions like reaction time and amount of solvent. These CoFe₂O₄ NPs exhibit morphology-dependent chemi-resistive humidity sensing behaviors. The highest humidity sensitivity value of ∼590 along with response/recovery value of 25/2.6 s at room temperature was obtained for CoFe₂O₄ hexagonal (CF-H) shape as compared to CoFe₂O₄ spherical (CF-S) and CoFe₂O₄ cubic (CF-C) shapes. Freundlich adsorption isotherm model was well fitted with the experimental results which turned up in support of a plausible humidity sensing mechanism. The morphology-dependent CoFe₂O₄ nanostructures exhibit promising sensing capabilities which ensure them as a potential candidate for magnetic recording media and next-generation humidity sensors.