The OH species is considered the main intermediate in many electrochemical reactions of interest, more specifically, those oxidation reactions where a source of oxygen is required. Thus, exploring the fundamental aspects of this adsorption process on Pt single crystals is essential. So far, it has been assumed that the OH adsorption only takes place at E>0.55 V vs. RHE on Pt [1,2], independently of the Pt surface structure. Nevertheless, we proved that OH is adsorbed at more negative potentials on the low coordinated Pt atoms (Pt steps) based on CO displacement experiments, alternating current voltammetry, and Raman spectroscopy results. We strongly believe that this finding opens new avenues in the fundamental research on the mechanism of several relevant electrochemical transformations, leading to better insights that could be the key for obtaining optimal catalysts for direct electrochemical applications of interest.

References

[1] Clavilier, J., Albalat, R., Gomez, R., Orts, J. M., Feliu, J. M. & Aldaz, A. Study of the charge displacement at constant potential during CO adsorption on Pt (110) and Pt (111) electrodes in contact with a perchloric acid solution. J. Electroanal. Chem. 330, 489–497 (1992).

[2] Climent, V., García-Araez, N., Herrero, E. & Feliu, J. Potential of zero total charge of platinum single crystals: A local approach to stepped surfaces vicinal to Pt (111). Russ. J. Electrochem. 42, 1145–1160 (2006).