ELLIPSOMETRIC, ELECTROCHEMICAL, AND ELEMENTAL CHARACTERIZATION OF THE SURFACE PHASE PRODUCED ON GLASSY-CARBON ELECTRODES BY ELECTROCHEMICAL ACTIVATION
ELLIPSOMETRIC, ELECTROCHEMICAL, AND ELEMENTAL CHARACTERIZATION OF THE SURFACE PHASE PRODUCED ON GLASSY-CARBON ELECTRODES BY ELECTROCHEMICAL ACTIVATION
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DOI：
10.1021/ac00165a022
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发表时间：
1988-07-15
影响因子：
7.4
通讯作者：
BARD, AJ
中科院分区：
文献类型：
--
作者：
KEPLEY, LJ;BARD, AJ
Ellipsometry was used to monitor the In situ growth of a film on a glassy carbon electrode, which was electrochemlcally anodized at 1.8 V In 0.1 M H2S04. The layer grew continu-ously In an uninhibited fashion with constant optical constants to a thickness of at least 925 nm. It was nearly transparent at wavelengths of 545 and 632.8 nm. X-ray and elemental analysis of bulk quantities of the phase Indicate that It Is an amorphous form of graphite oxide. Combined ellipsometric and electrochemical measurements show that the phase ac-tivates the surface and that deactivation occurs upon ex-tennslve reduction of the layer. The electrode activity, as monitored by the voltammetrlc response In dilute solutions of catechol, hydroqulnone, and 2, 3-dlcyanohydroqulnone, varied with the extent of reduction of the layer.Surface treatments have been used extensively to improve the electrochemical performance of several types of carbon electrodes: vitreous (glassy) carbon (1-7), pyrolytic graphite (8-10), carbon paste (11, 12), carbon fibers (13, 14). Surface activation has been accomplished by chemical oxidation with chromic acid (1, 9), exposure to an rf plasma in an oxygen atmosphere (10), heat treatment (15, 16), exposure to strong laser light pulses (17), and electrochemical anodization (1-8, 12-14). The studies described here were undertaken to obtain additional information about the nature of the surface changes that occur upon anodic activation of carbon. We describe in situ ellipsometricmeasurements, as well as ex situ charac-terization by X-ray powder diffraction and elemental analysis of the phase that forms during activation. To our knowledge no previous ellipsometric studies of carbon activation have appeared.
