Angle-dependent infrared absorption spectroscopy at electrode/electrolyte interf

2019-07-25 18:24:01

The film PT electrolyte dependent

责任者: Loster, M.;Friedrich, K.A. 单位: Physik-Department E19, Technische Universitat Munchen, 85748 Garching, Germany 来源出处: Surface Science,2003,523(3):287-297 摘要: Angle-dependent internal reflection spectroscopy is performed in the attenuated total reflection setup for an electrochemical cell with a Fourier transform infrared spectrometer. The working electrode is a thin Pt film evaporated onto a hemispherical Si prism. The refractive index of the Pt film obtained from the experiment is found to differ from the value for bulk material. The difference is ascribed to the surface corrugation of the Pt surface and the film thickness in the nanometer range. The function of reflection intensity versus angle of incidence changes significantly when a resonant absorption occurs in the electrolyte medium. The angle-dependent absorption band intensity of CO adsorbed on the Pt film under potential control reveals changes in magnitude and an inversion of the band for different angles of incidence. This behaviour is explained by the excitation of resonant surface plasmon waves at the Pt/electrolyte interface and by multiple reflections occurring at the interfaces. A simulation for the three-layer system Si/Pt/electrolyte agrees with the experimental results. © 2002 Elsevier Science B.V. All rights reserved. 关键词: Electrolytes;Electrodes;Interfaces (materials);Infrared radiation;Evaporation;Absorption spectroscopy;Metal-electrolyte interfaces