Dissolution of Platinum Single Crystal Surfaces under Potential Cycling in Sulfuric Acid Solution

Abstract

The dissolution of Pt(100), Pt(110), and Pt(111) single crystal surfaces under potential cycling conditions in 0.5 M H2SO4 solution was investigated by electrochemical measurements, ICP-MS analyses, and EC-STM observations. Pt(111) surface had higher corrosion resistance than Pt(100) and Pt(110) during potential cycles in 0.5 M H2SO4 solution, and hardly dissolved in the potential range below 1.2 V. EC-STM observations revealed the step structures became straight in the Pt(100) surface and the roughness in Pt(111) terraces gradually increases by the potential cycling in the range of 0.5 – 1.4 V. The formation of Pt islands with a higher surface energy by the potential cycling brought the increase of Pt dissolution rate in the Pt(111) surface with the number of cycle.

Atomic-Scale Identification of the Electrochemical Roughening of Platinum

“…However, the reactivities of terrace sites that are immediately adjacent to a vacancy are affected nonetheless. As the surface roughening is (almost completely) mass conserved, the total number of vacancies (single vacancies and vacancy islands) must be the same as the number of adatoms forming the average island shape. − This enables us to describe the expected vacancy-related signal. First of all, this signal depends on the number of created adatoms, which determines both the number of vacancy sites and the number of unaffected terrace sites.…”

Dissolution of Platinum Single Crystals in Acidic Medium

“…Comparing to the CVs taken in the bulk glass cell, the current densities are slightly diminished and some changes in the CV profiles are identified, which is likely due to small amounts of contaminations in this setup with increased complexity. However, we believe this to have a minimal impact on irreversible oxide formation and reduction and the subsequent dissolution, as has been previously suggested, while contaminations≥300 ppm typically cause severe changes in the CVs . Furthermore, the high reproducibility of the dissolution experiments suggests relatively clean surfaces.…”

“…However, platinum single crystal electrochemistry remains a highly active field of research, including electrocatalytic activity studies, investigations on improved preparation methods and the use of advanced in situ characterization techniques to understand surface oxide formation and reduction . Despite this recent interest, very little literature is currently available on platinum single crystal transient dissolution …”

“…[40][41][42] Despite this recent interest, very little literature is currently available on platinum single crystal transient dissolution. [43][44][45] Most notable in Pt single crystal transient dissolution has been the recent works of Lopes et al [44,45] Using the technique referred to as a stationary probe rotating disk electrode coupled to an inductively coupled plasma mass spectrometer (SPRDE-ICP-MS), key aspects of dissolution on the platinum single crystal basal planes were observed. The effect of reaction conditions was explored for the surfaces of Pt(111), Pt(100) and Pt(110) in 0.1 M HClO 4 electrolyte.…”

Correlation of surface site formation to nanoisland growth in the electrochemical roughening of Pt(111)

“…However, a small fraction of a monolayer of platinum dissolves during each ORC 31,32 . Moreover, the amount of Pt that dissolves during each ORC increases with increasing cycle number for at least 100 ORCs 47 . Although it would be possible to reach a steadystate surface structure while losing material into the electrolyte during each cycle 42,43 , the fact that the dissolved amount changes with each cycle means that the surface can not reach such a steady state.…”