Kinetic Isotope Effects Quantify pH-Sensitive Water Dynamics at the Pt Electrode Interface

The pH-dependent kinetics of the hydrogen oxidation and evolution reactions (HERs and HORs) remain a fundamental conundrum in modern electrochemistry. Recent efforts have focused on the impact of the interfacial water network on the reaction kinetics. In this work, we quantify the importance of inte...

Full description

Saved in:
Bibliographic Details
Published inThe journal of physical chemistry letters Vol. 11; no. 6; pp. 2308 - 2313
Main Authors Rebollar, Luis, Intikhab, Saad, Snyder, Joshua D, Tang, Maureen H
Format Journal Article
LanguageEnglish
Published United States American Chemical Society 19.03.2020
Online AccessGet full text

Cover

More Information
Summary:The pH-dependent kinetics of the hydrogen oxidation and evolution reactions (HERs and HORs) remain a fundamental conundrum in modern electrochemistry. Recent efforts have focused on the impact of the interfacial water network on the reaction kinetics. In this work, we quantify the importance of interfacial water dynamics on the overall hydrogen reaction kinetics with kinetic isotope effect (KIE) voltammetry experiments on single-crystal Pt(111) and Pt(110). Our results find a surface-sensitive KIE for both the HER and the HOR that is measurable in base but not in acid. Remarkably, the HOR in KOD on Pt(111) yields a KIE of up to 3.4 at moderate overpotentials, greater than any expected secondary KIE values, yet the HOR in DClO4 yields no measurable KIE. These results provide direct evidence that solvent dynamics play a crucial role in the alkaline but not in the acidic hydrogen reactions, thus reinforcing the importance of “beyond adsorption” phenomena in modern electrocatalysis.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.0c00185