[基础科学]简单的方法研究电子转移过程.pdf

9850 J. Phys. Chem. B 1998, 102, Simple Electrochemical Procedure for Measuring the Rates of Electron Transfer across Liquid/Liquid Interfaces Formed by Coating Graphite Electrodes with Thin Layers of Nitrobenzene Chunnian Shi and Fred C. Anson* Arthur Amos Noyes Laboratories, Di ision of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 Recei ed: June 12, 1998; In Final Form: September 28, 1998 A simple, new method is described that allows the rates of electron transfer across liquid/liquid interfaces to be measured with unprecedented ease. The method takes advantage of thin layers of organic liquids that adhere to the surface of pyrolytic graphite electrodes. The method was applied to the nitrobenzene/water interface. Redox reactants dissolved in the nitrobenzene included decamethylferrocene and zinc tetraphenyl- porphyrin. Reactants in the adjoining aqueous phase were multiply charged anions, including Fe(CN)63/4, Ru(CN)64, Mo(CN)84, and IrCl62. Rate constants for cross-phase electron transfer were evaluated and compared with those obtained in recent studies that employed the scanning electrochemical microscope that was invented and developed by A. J. Bard and co-workers. The examination of electron transfer across interfaces separat- ing two immiscible liquids has received increasing attention in the past decade.1 One of the newest experimental methods that has been used to measure the rates of such electron-transfer processes is scanning electrochemical microscopy (SECM), a technique invented and extensively applied by Bard