Understanding the pH Dependence of Underpotential Deposited Hydrogen on Platinum. Issue 49 (6th November 2019)

• Record Type: Journal Article
• Authors: Yang, Xuan; Nash, Jared; Oliveira, Nicholas; Yan, Yushan; Xu, Bingjun
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 49(2019)
• Page Start: 17718
• Page End: 17723
• Publication Date: 2019-11-06
• Subjects: interfacial water structure -- pH dependence -- SEIRAS -- specific adsorption -- underpotential deposited hydrogen; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201909697
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Understanding the pH dependent shift of the oxidation peak of the underpotential deposited hydrogen (Hupd ) in cyclic voltammograms on the Pt surface is of significance in terms of both the fundamentals of electrochemistry and the rational design of catalysts for the hydrogen oxidation/evolution reactions (HOR/HER). In this work, we provide compelling evidence that the pH dependent shift in the Hupd peak on Pt surfaces is driven by the structure of interfacial water rather than the specific adsorption of cations on the electrode surface. Combined cyclic voltammetric and surface enhanced spectroscopic investigations using an organic cation and crown‐ether chelated alkali metal cations show that specific adsorption of metal and organic cations on the Pt surface at the conditions relevant to the HOR/HER is unlikely. The vibrational band corresponding to strongly bound water is monitored when the electrode potential is varied in the Hupd range in both acid and base. Abstract : The pH dependent shift in the Hupd peak on Pt surfaces is demonstrated to be driven by the structure of interfacial water rather than the specific adsorption of cations on the electrode surface. The direct water‐electrode interaction, which is dependent on the absolute electrode potential, likely holds the key to understanding the pH induced Hupd peak shift on the Pt surface.