Infrared and
R
aman Spectroscopy in Analysis of Surfaces
Authors: Tian Zhong‐Qun , Ren Bin 
Published: September 2006

Infrared (IR) spectroscopy and Raman spectroscopy are important analytical instrumental techniques for surface science. An analytically useful fingerprint spectrum can be recorded from almost any surface. As a consequence, surface IR and Raman spectroscopies find extensive application in qualitative analysis, providing either functional group or structural information about a surface, and determining surface bonding, conformation and orientation. More importantly, these two vibrational spectroscopies can be applied under in situ conditions of solid–gas, solid–liquid and solid–solid interfaces of both fundamental and practical importance. They can also very successfully be used for studies of surface dynamics and ill‐defined high‐surface‐area porous materials, to which many surface techniques are not applicable. Therefore, IR and Raman spectroscopies are among the most promising and most widely used methods for surface science. However, there is great limitation when these two techniques are applied to the detection of surface species of ten times less than a monolayer. Their surface sensitivities, especially for Raman spectroscopy, are remarkably lower than that of ultra high vacuum (UHV)‐based electron energy loss spectroscopy (EELS) technique. Fortunately, surface‐enhanced Raman spectroscopy (or scattering) (SERS) and surface‐enhanced infrared absorption (SEIRA) can improve the sensitivity significantly by several orders of magnitude for roughened surfaces of noble and transition metals.

This article first concisely outlines the basic principles and opportunities of surface IR and Raman spectroscopy followed by a description of SERS and SEIRA phenomena as well as techniques in more detail. A brief survey of the histories of surface IR spectroscopy and surface Raman spectroscopy is then given. Comparisons are made between surface IR and surface Raman spectroscopies on the sensitivities, surface enhancement, instrumental methods and applications. Emphasis is placed on their ability to deliver specific chemical identifications, coupled with the wide range of instrumental and sampling methodologies available and related phenomena in terms of the fundamental and instrumental parameters which affect the surface signal intensity. Important factors are recognized and prioritized to extend the general utilities of surface IR and surface Raman spectroscopy to in situ studies on solid–gas, solid–liquid and solid–solid interfaces under various conditions with changing temperature, pressure, media and electrode potential. Some newly developing techniques for surface science, such as single molecule Raman spectroscopy, IR and Raman microscopies and imaging techniques, time‐resolved IR and Raman spectroscopies, and ultraviolet (UV) resonance Raman spectroscopy, are introduced with representative examples. Thetroubleshooting section deals with some problems commonly encountered in the study, e.g. low detection sensitivity, surface heating and damage by laser, fluorescence elimination, coupling with transient measurement, and spectral data analyzing. Applications are exemplified on extensively studied areas such as in advanced materials, catalysis, electrochemistry, corrosion, biology and sensor. Finally, prospects and further developments of this field are given with emphasis on the emerging as well as promising methodologies in view of surface preparation, instrumentation and hyphenated techniques.