FePt-Au ternary metallic nanoparticles with the enhanced peroxidase-like activity for ultrafast colorimetric detection of H2O2

Abstract In this paper, FePt-Au ternary metallic hybrid nanaoparticles (FePt-Au HNPs) were prepared with FePt nanocubes as seeds and then the seeds were combined with Au(I) precursor through a facile hydrothermal approach. And the FePt-Au HNPs were characterized by a series of technical methods such as transmission electron microscopy (TEM), X-ray diffraction pattern (XRD) and UV–vis absorption spectra. Moreover, the as-prepared FePt-Au HNPs possessed the excellent peroxidase-like activity which could rapidly catalyze the oxidation reaction of substrate 3,3′,5,5′ −tetramethylbenzidine (TMB) to obtain a typical blue product which could be observed apparently by the naked eye only within 30 s. Notably, the color response is instant, due to the fast electron transfer between the substrate and H 2 O 2 with the aid of FePt-Au HNPs. Based on the catalytic mechanism of fast electron transfer and the intrinsic peroxidase-like activity of FePt-Au HNPs, a visual colorimetric sensor for ultrafast detecting H 2 O 2 was constructed with a wide linear range of 20–700 μM as well as a relative lower limit of detection (LOD) of 12.33 μM. Furthermore, the ultrafast sensor based on FePt-Au HNPs as peroxidase mimics was also successfully applied to detect H 2 O 2 in milk samples.