In situ controllable growth of CoFe2O4 ferrite nanocubes on graphene for colorimetric detection of hydrogen peroxide

Abstract

A facile method is proposed for the synthesis of cubic CoFe₂O₄ ferrite–reduced graphene oxide nanocomposite sheets (rGO–CFs), using poly(N-vinyl-2-pyrrolidone) as the reductant and stabilizer. The rGO–CFs functioned as efficient peroxidase mimetics and were successfully applied for colorimetric assay. The morphology and composition of the rGO–CFs were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Significantly, the peroxidase-like activity of the rGO–CFs followed typical Michaelis–Menten kinetics and showed a good affinity to 3,3,5,5-tetramethyl benzidine. Under optimum conditions, the colorimetric assay showed a lower detection limit (S/N = 3) of 0.3 μM when compared with that of other nanoparticle based colorimetric assays. Furthermore, the cubic nanostructured rGO–CFs exhibited better stability than horseradish peroxidase when they were exposed to solutions with different solvents and temperatures. These excellent properties made the cubic nanostructured rGO–CFs an ideal candidate for a wide range of potential applications as peroxidase mimetics.