Electric Double Layer Effects in Electrocatalysis: Insights from Ab Initio Simulation and Hierarchical Continuum Modeling

Abstract

Structures of the electric double layer (EDL) at electrocatalytic interfaces, which are modulated by the material properties, the electrolyte characteristics (e.g., the pH, the types and concentrations of ions), and the electrode potential, play crucial roles in the reaction kinetics. Understanding the EDL effects in electrocatalysis has attracted substantial research interest in recent years. However, the intrinsic relationships between the specific EDL structures and electrocatalytic kinetics remain poorly understood, especially on the atomic scale. In this Perspective, we briefly review the recent advances in deciphering the EDL effects mainly in hydrogen and oxygen electrocatalysis through a multiscale approach, spanning from the atomistic scale simulated by ab initio methods to the macroscale by a hierarchical approach. We highlight the importance of resolving the local reaction environment, especially the local hydrogen bond network, in understanding EDL effects. Finally, some of the remaining challenges are outlined, and an outlook for future developments in these exciting frontiers is provided.

Pt single crystal surfaces in electrochemistry and electrocatalysis

“…[111][112][113][114][115] Those results highlight the importance of the local hydrogen-bond network in the structure and properties of the double layer, which affects the electrocatalysis. 105 GC-DFT 111 and AIMD 116 have been able to reproduce the capacity maximum around the pzfc, and the existence of an ion distribution that does not follow the mean-field Poisson-Boltzmann distribution. 43 Author contributions J. M. F. Conceptualization, formal analysis, resources, writingreview & editing.…”

“…In fact, recent results in the modeling of the double layer and its impact on electrocatalysis reveal that the local hydrogen-bond network in the water has important effects on the structure and properties of the double layer, shaping the electrocatalytic process. 105 In order to improve implicit solvation models, which computationally are less demanding, parameterized implicit solvation models have been proposed that can reproduce experimental results and those obtained with explicit water models. 106 Another important conclusion obtained from models trying to reproduce experimental results is that the electrostatic interactions are much stronger than those expected by the mean-field Poisson–Boltzmann equation, 38 as observed from the experimental results of the effect of the concentration in the capacity minimum around the pzfc for the Pt(111) electrode.…”

Mechanistic Insights into Surfactant-Modulated Electrode–Electrolyte Interface for Steering H2O2 Electrosynthesis

“…Also, the addition of organic solvents can regulate the interfacial hydrogen-bond network by altering the solvation structure, thus affecting the PCET kinetics. , Ionic surfactants, a class of molecules that can significantly alter interfacial properties, are often employed as interface modifiers to modulate the electrode–electrolyte interface. ,, For example, our previous work has revealed that cationic surfactants can form a nearly ordered assembly under a favorable bias potential window. The assembly enables the H 2 O decrease and CO 2 enrichment at the interface, favoring the CO 2 reduction and inhibiting the H 2 evolution reaction. − Nevertheless, a molecular-level understanding and corresponding regulation strategy toward the proton transfer process of ORR from the view of the interfacial hydrogen-bond network are still lacking.…”

Constant Potential Thermodynamic Integration for Obtaining the Free Energy Profile of Electrochemical Reaction

“…This is because that the potential contributions to electron transfer are described by a basic capacitor model in CEM, where the number of transferred charges from initial to final states give the potential dependence of an electrochemical reaction energy. Evidently, this method overlooks other possible potential-induced contributions such as solvation energy contribution which is crucial in many electrocatalytic processes. , In contrast, the slope of linear relationships derived by the CPTI method (1.63) is larger than the Δ N trans (Figure b). Note the slope derived by CPTI is basically consistent with our previous normal thermodynamic integration calculations with counterions for controlling potentials, where we obtained the slope from variable pathways under different potentials .…”