A seed-mediated method to design N-doped graphene supported gold-silver nanothorns sensor for rutin detection

In this paper, a novel Au-Ag nanothorns (NT) composite has been synthesized through a seed-mediated mild chemical route, and then assembled on N-doped graphene (NG). The composite (Au-Ag NTs/NG) was characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Furthermore, electrochemical activity of as-prepared Au-Ag NTs/NG was investigated by cyclic voltammetry (CV) and different pulse voltammetry (DPV). In CVs of Au-Ag NTs, NG, and Au-Ag NTs electrodes recorded in 0.1 M PBS (pH = 3.0) containing 0.1 mM rutin, a remarkably large peak current (55 μA) was obtained on Au-Ag NTs/NG compared to those for NG (25 μA) and Au-Ag NTs (6.2 μA) demonstraing the remarkably enhanced electrochemical activity of the Au-Ag NTs/NG as compared to Au-Ag NTs/NG and NG modified onto a glassy carbon electrode. Electrochemical measurements indicated that the sensors made by Au-Ag NTs/NG electrode are very sensitive and selective for rutin detection due to the NT structure and effects of NG and Au-Ag NTs. In the DPV, Au-Ag NTs/NG electrode was found to have a linear response in the range of 0.1-420 μM and a comparable low detection limit of 0.015 μM (S/N = 3). These results demonstrate that Au-Ag NTs/NG has great potential in extending application in sensor field as the efficient material.