Unveiling the Role of Oxidation Debris on the Surface Chemistry of Graphene through the Anchoring of Ag Nanoparticles
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- 作者：Andr茅ia F. Faria ; Diego St茅fani T. Martinez ; Ana C. M. Moraes ; Marcelo E. H. Maia da Costa ; Eduardo B. Barros ; Antonio G. Souza Filho ; Amauri J. Paula ; Oswaldo L. Alves
- 刊名：Chemistry of Materials
- 出版年：2012
- 出版时间：November 13, 2012
- 年：2012
- 卷：24
- 期：21
- 页码：4080-4087
- 全文大小：580K
- 年卷期：v.24,no.21(November 13, 2012)
- ISSN：1520-5002
文摘
The surface microchemical environment of graphene oxide (GO) has so far been oversimplified for understanding practical purposes. The amount as well as the accurate identification of each possible oxygenated group on the GO surface are difficult to describe not only due to the complex chemical nature of the oxidation reactions but also due to several intrinsic variables related to the production and chemical processing of GO-based materials. However, to advance toward a more realistic description of the GO chemical environment, it is necessary to distinguish the oxygenated fragments with very peculiar characteristics that have so far been treated as simply graphene oxide. In this way, small oxidized graphitic fragments adsorbed on the GO surface, named oxidation debris or carboxylated carbonaceous fragments (CCFs), have been here separated from commercially available GO. Spectroscopy and microscopy results indicated that the chemical nature of these fragments is different from that of GO. By using the decoration of GO with silver nanoparticles as a conceptual model, it was seen that the presence of oxidation debris on the GO surface greatly influences the associated kinetic processes, mainly due to the nucleation and stabilization capacity for silver nanoparticles provided by the oxidation debris fragments. Consequently, when CCFs are present, Ag nanoparticles are significantly smaller and less crystalline. Considering the GO microchemical environment pointed out here, these findings can be qualitatively extrapolated to all other covalent and noncovalent functionalizations of GO.