Silver nanoparticles selectively deposited on graphene-colloidal carbon sphere composites and their application for hydrogen peroxide sensing

In this study, we report the fabrication of a novel graphene-colloidal carbon sphere composite decorated with silver nanoparticles (Gr-CCS-AgNPs). Graphene-colloidal carbon sphere (Gr-CCS) and silver nanoparticles (AgNPs) were prepared under hydrothermal conditions step by step. The obtained Gr-CCS-AgNPs composite was characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffracmeter (XRD), X-ray photoelectron spectroscopy (XPS) and the energy dispersive X-ray spectroscopy (EDX), and a forming mechanism was suggested. A glassy carbon electrode was modified with the Gr-CCS-AgNPs to construct an electrochemical sensor, and our results demonstrated that the modified electrode had electrocatalytic activity for the reduction of hydrogen peroxide (H2O2) in 0.1 M phosphate buffer solution (PBS, pH = 7.0). The proposed H2O2 sensor displayed many good characteristics, such as a simple preparation procedure, fast amperometric response time (approximately 1 s), excellent selectivity and sensitivity. The first linear section was in the range of 2 x 10(-5) M to 5.02 x 10(-3) M with a correlation coefficient of 0.9998 and a limit of detection of 2.49 mu M (S/N ratio is 3). The second linear response occurred from 5.02 x 10(-3) M to 3.41 x 10(-2) M with a correlation coefficient of 0.9995 and a limit of detection of 9.51 mu M (S/N ratio is 3). (C) 2016 Elsevier B.V. All rights reserved.