Voltammetry plays a crucial role in modern scientific research by offering valuable insights into the electrochemical properties of materials, with wide-ranging applications in fields such as... Show moreVoltammetry plays a crucial role in modern scientific research by offering valuable insights into the electrochemical properties of materials, with wide-ranging applications in fields such as materials science, energy storage, corrosion studies, and sensor development.Gold, known for its exceptional inertness, provides a unique platform for studying intricate electrochemical processes due to its stability and slow electrochemical behavior. However, certain questions regarding gold voltammetry have remained unresolved throughout history. To address these gaps, our research employed a combination of electrochemical cyclic voltammetry and advanced in situ techniques like surface-enhanced Raman spectroscopy (SERS), Rotating ring-disk electrode (RRDE), and Electrochemical quartz crystal microbalance (EQCM).Through our investigations, we not only redefined the mechanism of gold oxide formation but also uncovered the reasons behind the structural reconstruction of gold oxide. Additionally, we elucidated the electrochemical interfacial structure on gold from a novel perspective focusing on charge distribution.The significance of these findings lies in their fundamental nature, with the potential to inspire researcher to reconsider interpretations of voltammetry behaviors across various materials and research fields. We anticipate that our work will stimulate further exploration and innovation in the realm of electrochemistry, paving the way for new discoveries and advancements. Show less
In most applications, electrocatalysts exhibit a large surface area to volume ratio, for example using nanoparticles. To fully understand fundamental electrochemical processes at the length scale... Show moreIn most applications, electrocatalysts exhibit a large surface area to volume ratio, for example using nanoparticles. To fully understand fundamental electrochemical processes at the length scale of these nanoparticles, it is necessary to use specialized experimental techniques. In this thesis, the stability and activity of platinum electrode surfaces are studied at the nano- and micrometer scale using Electrochemical Scanning Probe Microscopy (EC-SPM) techniques. Chapters 2 and 3 describe the roughening of an atomically flat Pt(111) surface upon repetitive oxidation and reduction. These data were acquired using a combination of Electrochemical Scanning Tunneling Microscopy (EC-STM) and Cyclic Voltammetry (CV). Chapter 4 describes the development of a new technique to resolve small differences in local reactivity: voltammetric Scanning Electrochemical Cell Microscopy (SECCM). The power of this technique is demonstrated by studying the reactivity of a polycrystalline Pt sample towards hydrazine oxidation. Finally, Chapter 5 compares the reactivity of small Pt ultramicroelectrodes to that of conventional macroelectrodes. Show less
