Electrochemical Processes Studied Ex-Situ with Ultrahigh Vacuum Surface Analysis

通过将超高真空（UHV）表面分析与电化学相结合，非原位研究为研究电化学现象提供了一种新的、非常详细的途径。该方法应用于甲醇和甲酸在单晶金属电极上的电催化研究。这些反应在燃料电池应用中很重要，但缺乏对机理的理解，特别是对自发中毒的理解，阻碍了进一步的发展。这项工作应用了气相多相催化的概念，为理解电催化行为建立了一个范例。结合特高压和电化学交叉表征实验以及在特高压下的电化学后分析，研究了单独和在改性剂存在下反应的机理细节。考察了金属和非金属改性剂的生长方式和表面化学性质。该研究直接解决了阻碍直接甲醇燃料电池发展的重要问题。然而，与这项重要技术的进步（由于能源资源的限制和环境方面的考虑）可能同样重要的是发展和改进用于研究电化学系统的非原位方法，这可能对工业过程工作产生重大影响。

By combining ultrahigh vacuum (UHV) surface analysis with electrochemistry, ex situ studies offer a new, vastly detailed route for examining electrochemical phenomena. This approach is applied to the study of methanol and formic acid electrocatalysis on single crystal, metal electrodes. These reactions are important in fuel-cell applications, but the lack of mechanistic understanding, particularly of spontaneous poisoning, inhibits further development. This work applies concepts from gas-phase heterogeneous catalysis to build a paradigm for understanding electrocatalytic behavior. The mechanistic details of the reactions, individually and in the presence of modifiers, are studied with a combination of UHV and electrochemical cross-characterization experiments and post-electrochemical analyses in UHV. The growth modes and surface chemistry of metallic and nonmetallic modifiers are examined as well. The research directly address the important issues that stand in the way of development of direct methanol fuel cells. However, of perhaps equal importance to the advancement of this important (because of energy resource limitations and environmental considerations) technology is the development and refinement of the ex situ methodology for the study of electrochemical systems, which could have a major impact on industrial process work.