In Situ FTIR Probing of Surface Ordering via CO Electrooxidation

Electrochemical reactions are surface-specific and morphology-dependent on the atomic scale. To understand and control the progression of electrochemical reactions, a precise knowledge of nanoscale surface morphology is essential. In situ FTIR is presented as a rapid, precise, and surface-sensitive probe to reveal the structural dependence of adsorbate behavior. Annealed Pt thin films are found to largely emulate (111) facet characteristics during CO electrooxidation; however, during thermal annealing, two stages of surface evolution are observed. First, an intermediary phase with finer grain size evolves before the growth of (111) domains, leading to extended terraces and classical (111) behavior. The method can be extended to assess the surface crystallinity of a range of active surfaces, from single-crystalline electrodes to nanostructured interfaces, which is particularly relevant where surface structures cannot be evaluated by conventional surface science techniques.