Intrinsic peroxidase-like activity and the catalytic mechanism of gold@carbon dots nanocomposites

Well-dispersed AuNPs@CDs nanocomposites were successfully synthesized from the reduction of chloroauric acid by carbon dots (CDs) at room temperature. The as-prepared AuNPs@CDs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), and the results indicate AuNPs@CDs nanocomposites with a core–shell structure. The AuNPs@CDs are found to possess intrinsic peroxidase-like activity, and the catalytic activity is higher than that of AuNPs. The mechanism of peroxidase-like activity of AuNPs@CDs was investigated by fluorescence spectroscopy, electron spin resonance and cyclic voltammetry, and it is found that the mechanism could be ascribed to facilitating the electron transfer between TMB and H2O2.