The frontiers of surface structure analysis

Abstract

Lowenergy electrons have been used predominantly to determine surface structure: low-energy electron difiaction (LEED) surface crystallography to identify the location of surface atoms and molecules, their site symmetry, bond distances and bond angles; and high-resolution electron energy-loss spectroscopy (HREELS) to determine the vibrational spectra of atoms and molecules at surfaces. The key findings of research using LEED and HREELS will be discussed. The new directions of research using these two techniques for studies of disordered surface layers and more complex molecules will be reviewed.Scanning tunneling microscopy (STM) and atomic force microscopy are new techniques under rapid development for surface structure determination. The combination of STM and LEED crystallography permits the quantitative validation of STM findings. Atomic spatial resolution uncovered several unexpected surface structures. The use of STM during high-pressure catalytic reactions is at the frontier of surface structure studies.Extended x-ray adsorption fine structure (EXAFS) and photoelectron difbaction have been used to study the atomic structure and coordination of clusters. Laser sum frequency generation (SFG) is employed to obtain vibrational spectra of molecules at solidJiquid and solid/solid interfaces. These techniques expand the frontiers of surface structure analysis to new types of surface and interface systems.

Operando spatially and time-resolved X-ray absorption spectroscopy and infrared thermography during oscillatory CO oxidation

“…Both single-crystal surfaces and real exhaust gas catalysts have been extensively studied, especially with respect to Pt-catalyzed CO oxidation as model reaction [22,[31][32][33][34][35][36][37][38][39][40][41]. In particular, oscillatory CO conversion behavior has received growing attention [42][43][44][45].…”

Time-Lapse STM Studies of Diastereomeric Cinchona Alkaloids on Platinum Metals

“…In recent years, several groups focused on molecule surface combinations related to heterogeneous catalysis [3][4][5] or even enantioselective heterogeneous catalysis. [6][7][8] In the latter case, STM investigations are of special interest, as the arrangement of the chiral molecules on the catalytic surface (chiral site/ extended chiral domain), which is crucial for the efficiency of the catalyst system, can be imaged in real space.…”

Electrochemistry at Well‐Characterized Bimetallic Surfaces

“…UHV surface-sensitive tools have been extensively used for determination of these critical parameters [Somorjai, 1992]. For instance, low energy electron diffraction (LEED) is a widely adopted tool to study the surface crystallography of various materials [Van Hove et al, 1986].…”