Electron Transfer Kinetics on Mono- and Multilayer Graphene

详细信息    查看全文

• 作者：Mat臎j Velick媒 ; Dan F. Bradley ; Adam J. Cooper ; Ernie W. Hill ; Ian A. Kinloch ; Artem Mishchenko ; Konstantin S. Novoselov ; Hollie V. Patten ; Peter S. Toth ; Anna T. Valota ; Stephen D. Worrall ; Robert A. W. Dryfe
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：8
• 期：10
• 页码：10089-10100
• 全文大小：722K
• ISSN：1936-086X

文摘

Understanding of the electrochemical properties of graphene, especially the electron transfer kinetics of a redox reaction between the graphene surface and a molecule, in comparison to graphite or other carbon-based materials, is essential for its potential in energy conversion and storage to be realized. Here we use voltammetric determination of the electron transfer rate for three redox mediators, ferricyanide, hexaammineruthenium, and hexachloroiridate (Fe(CN)₆3鈥?/sup>, Ru(NH₃)₆³⁺, and IrCl₆2鈥?/sup>, respectively), to measure the reactivity of graphene samples prepared by mechanical exfoliation of natural graphite. Electron transfer rates are measured for varied number of graphene layers (1 to ca. 1000 layers) using microscopic droplets. The basal planes of mono- and multilayer graphene, supported on an insulating Si/SiO₂ substrate, exhibit significant electron transfer activity and changes in kinetics are observed for all three mediators. No significant trend in kinetics with flake thickness is discernible for each mediator; however, a large variation in kinetics is observed across the basal plane of the same flakes, indicating that local surface conditions affect the electrochemical performance. This is confirmed by in situ graphite exfoliation, which reveals significant deterioration of initially, near-reversible kinetics for Ru(NH₃)₆³⁺ when comparing the atmosphere-aged and freshly exfoliated graphite surfaces.

Keywords:

graphene; graphite; basal plane; electron transfer; kinetics; electrochemistry; voltammetry