Modeling Electrified Pt(111)-Had/Water Interfaces from Ab Initio Molecular Dynamics

Jia-Bo Le; Ao Chen; Lang Li; Jing-Fang Xiong; Jinggang Lan; Yun-Pei Liu; Marcella Iannuzzi; Jun Cheng

doi:10.1021/jacsau.1c00108

Modeling Electrified Pt(111)-H_ad/Water Interfaces from Ab Initio Molecular Dynamics

JACS Au. 2021 Apr 6;1(5):569-577. doi: 10.1021/jacsau.1c00108. eCollection 2021 May 24.

Authors

Jia-Bo Le^{1

2}, Ao Chen¹, Lang Li¹, Jing-Fang Xiong¹, Jinggang Lan³, Yun-Pei Liu¹, Marcella Iannuzzi³, Jun Cheng¹

Affiliations

¹ State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
² Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
³ Department of Physical Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.

Abstract

Unraveling the atomistic structures of electric double layers (EDL) at electrified interfaces is of paramount importance for understanding the mechanisms of electrocatalytic reactions and rationally designing electrode materials with better performance. Despite numerous efforts dedicated in the past, a molecular level understanding of the EDL is still lacking. Combining the state-of-the-art ab initio molecular dynamics (AIMD) and recently developed computational standard hydrogen electrode (cSHE) method, it is possible to realistically simulate the EDL under well-defined electrochemical conditions. In this work, we report extensive AIMD calculation of the electrified Pt(111)-H_ad/water interfaces at the saturation coverage of adsorbed hydrogen (H_ad) corresponding to the typical hydrogen evolution reaction conditions. We calculate the electrode potentials of a series of EDL models with various surface charge densities using the cSHE method and further obtain the Helmholtz capacitance that agrees with experiment. Furthermore, the AIMD simulations allow for detailed structural analyses of the electrified interfaces, such as the distribution of adsorbate H_ad and the structures of interface water and counterions, which can in turn explain the computed dielectric property of interface water. Our calculation provides valuable molecular insight into the electrified interfaces and a solid basis for understanding a variety of electrochemical processes occurring inside the EDL.