▎ 摘　　要

A green chemical approach to control the dimensions of Ag nanoparticle-decorated graphene oxide (AgNP-GO) composites was proposed by in situ ultrasonication of a mixture of AgNO3 and GO solution with the assistance of vitamin C acting as an environmentally friendly reducing agent at room temperature. The AgNP-GO composites were characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, Raman spectra and ultraviolet visible absorption spectra. The results demonstrated that Ag nanoparticles with an average diameter of similar to 15 nm were uniformly dispersed on the surface of GO nanosheets by in situ ultrasonication of 1 min with vitamin C. Increasing the ultrasonication times resulted in Ag nanoparticles with tunable dimensions ranging from 15 to 55 nm being formed on the surface of GO nanosheets. The amount of silver nitrate and the ultrasonication time play a key role in the control of the dimension of Ag nanoparticles on GO, and a formation mechanism of the asprepared AgNP-GO composites is proposed. This study provides a guide to controlling the dimensions of AgNP-GO composites, which may hold promise as advanced materials for various analytical applications such as catalysis, sensors and microchips. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.