MULTIMETHOD ANALYSIS OF THE METAL ELECTROLYTE INTERFACE - SCANNING FORCE MICROSCOPY (SFM), QUARTZ MICROBALANCE MEASUREMENTS (QMB), FOURIER-TRANSFORM INFRARED-SPECTROSCOPY (FTIR) AND GRAZING-INCIDENCE X-RAY-DIFFRACTOMETRY (GIXD) AT A POLYCRYSTALLINE COPPER ELECTRODE/

The successful application of various in situ and ex situ analytical t echniques has been demonstrated at the buried interface between a meta l and an electrolyte. Scanning force microscopy (SFM), electrochemical quartz microbalance measurements (EQMB), grazing incidence x-ray diff ractometry (GIXD), Fourier transform infrared spectroscopy (FTIR) in t he specular reflection absorption mode and electrochemical charge meas urements proved complementary in the characterization of a polycrystal line copper electrode in alkaline 0.1 M sulphate, perchlorate, fluorid e and chloride electrolyte contact at pH 12. The surface exhibited a m ixture of Cu(lll) and Cu(200) grains of the order of 100 nm. Repeated potential scanning in the double layer and passive oxide region, betwe en -1.4 and +0.1 V-MSE, resulted in a complete reorganization of the s urface morphology but no detectable corrosion. The electrochemical exc hange of H2O and OH- between the electrolyte and the oxide film took p lace reversibly in accordance with a solid-state growth mechanism. The copper atoms were redeposited at crystallographically preferred sites , generating comparatively homogeneously oriented, narrow Cu(lll)-edge d grain ridges of length similar to 200 nm. In the Cu(I) potential ran ge, the formation of several monolayers of amorphous Cu2O could be con firmed. Only after extended time periods in the Cu(II) oxide potential region, Cu2O recrystallized to a (111) phase accompanied by Cu2O(200) and Cu2O(110). In this region, one observed the formation of amorphou s Cu(OH), concurrent with further growth of Cu2O. Strong CuO-H IR stre tching bands excluded the existence of CuO. At corrosive potentials of +0.25 V-MSE, high anodic currents and substantial mass losses led to an electropolished surface with isolated features of <300 nm width and <70 nm height. (C) 1997 by John Wiley & Sons, Ltd.