Oxidation of Platinum in the Epitaxial Model System Pt(111)/YSZ(111): Quantitative Analysis of an Electrochemically Driven PtO_xFormation

Abstract

The oxidation of platinum (Pt) plays a key role in electrochemistry, both in the solid and liquid state, and in surface science. This work provides a comprehensive comparison of current knowledge of Pt oxidation in these three fields. By presenting new data of the solid state epitaxial model-type interface Pt(111)/yttria-stabilized zironia (YSZ(111)), fundamental insights are obtained: (i) analogous features in cyclic voltammograms of the interfaces Pt(111)/acid aqueous electrolyte and Pt(111)/YSZ(111) are correlated and their differences explained. (ii) By comparing the cathodic peak shapes of cyclic voltammograms of Pt/YSZ to temperature-programmed desorption spectra, the peaks can be attributed to an adsorption and an oxide-like state of oxygen. (iii) The linearity between the accumulation of oxygen at the Pt electrode and the logarithm of polarization time for sufficiently high anodic potentials, which is well-known in aqueous electrochemistry, is also found at the interface Pt/YSZ for the first time, and the mechanism leading to this time law is discussed.

The Hidden Pathways in Dense Energy Materials – Oxygen at Defects in Nanocrystalline Metals

“…The shape suggests strongly that this is a Pt triple line, i.e., a line defect, decorated with PtO x . This experimentally confirms for the first time the presence of PtO x , both at Pt surfaces and at nanoscopic three‐phase boundaries, as postulated previously based on impedance spectroscopy and cyclic voltammetry experiments . With the knowledge of the PtO x concentration in the bulk, and along the line defects from APT, the diffusion properties in nanocrystalline Pt can be examined.…”

On the Additive Microstructure in Composite Cathodes and Alumina-Coated Carbon Microwires for Improved All-Solid-State Batteries

“…As a result, the theoretical analysis of diffusion-controlled CV peaks is strictly no longer applicable and a quantitative analysis of reversibility can easily be misleading. 45,46 Therefore, we do not identify decomposition products and possible mechanisms from the CV data but refer to our XPS analysis.…”

“…In solid-state cells, reaction conditions (e.g., limited mobility but also energetic or kinetic changes) are different to the liquid counterpart. As a result, the theoretical analysis of diffusion-controlled CV peaks is strictly no longer applicable and a quantitative analysis of reversibility can easily be misleading. , Therefore, we do not identify decomposition products and possible mechanisms from the CV data but refer to our XPS analysis.…”

Thin film cathodes in SOFC research: How to identify oxygen reduction pathways?

“…To systematically investigate elementary steps of electrode reactions, geometrically well-defined model electrodes have therefore been introduced to solid state electrochemistry. 7,8,11,26,[30][31][32][33][34][35][36][37][38] Such model systems-which are usually prepared by photolithographical patterning of thin films-offer the opportunity of controlling and tuning geometric parameters such as surface area, film thickness, or TPB length. A defined variation of the electrode geometry can be extremely helpful for the electrochemical interpretation of experimental results.…”