• 文献标题:   Stabilization of Phenolic Radicals on Graphene Oxide: An XPS and EPR Study
  • 文献类型:   Article
  • 作  者:   STATHI P, GOURNIS D, DELIGIANNAKIS Y, RUDOLF P
  • 作者关键词:  
  • 出版物名称:   LANGMUIR
  • ISSN:   0743-7463
  • 通讯作者地址:   Univ Groningen
  • 被引频次:   27
  • DOI:   10.1021/acs.langmuir.5b01248
  • 出版年:   2015

▎ 摘  要

A graphene oxide-gallic acid hybrid material was synthesized by the immobilization of gallic acid (3,4,5-trihydroxobenzoic acid) on graphene oxide. The grafting was achieved via the formation of amide bonds between the amine groups on the organofunctionalized graphite oxide surface and the carboxyl groups of the gallic acid molecules. The EPR signal of the gallic acid radicals in this hybrid material remained almost unaltered over at least 500 days, with less than 3% signal decay over that period, pointing to the truly remarkable stability of these radicals. The produced material was characterized by Fourier transform infrared, X-ray photoelectron, and electron paramagnetic resonance spectroscopies as well as by thermogravimetric analysis and the Kaiser test. The stability of the radicals in the material was studied in powder form and in aqueous solution vs pH. We demonstrate that in the graphene oxide-gallic acid hybrid material a radical is favorably stabilized on the ring-O while the oxidation of the second OH is precluded, and this results in long-term stabilization of the gallic acid radicals in solid hybrid material. Thus, in applications where it will be used under O-2-free and humidity-free conditions, the graphene oxide-gallic acid hybrid material is a reliable spintronics scaffold.