(187d) DFT Models to Understand the Effect of Interfacial Modification on Electrocatalysis

Electronic structure calculations of electrocatalytic processes make choices of how, or whether, to include solvation interactions with the electrolyte or the electrification and charge separation of the electrochemical double-layer. Without these features in the model, the impact of the electrochemical interfacial properties on electrocatalytic energetics are neglected. However, activity and selectivity of electrochemical reactions can significantly be impacted by changes in the composition and structure of the electrolyte-side of electrode/electrolyte interface. The presence of “spectator” ions has shown to affect the electrocatalyst performance for HER/HOR [1]. The presence and eventual co-adsorption of organic proton donor co-catalysts in the interfacial region has been shown to affect the rate of the CO₂ reduction [2]. Representation of electrolyte impacts on electrocatalytic reactions in DFT models is essential to provide mechanistic explanations for these phenomena and guide rational design of the electrode/electrolyte interface. In this talk, we will discuss our use of density functional theory (DFT) calculations to model these interfacial effects. We implement constant voltage DFT models using explicit charging along with both explicit and continuum solvation. We will discuss results using these models to examine the role of alkali cations in the interfacial region and their effect on intermediate adsorption and reaction. We will also examine how molecular co-catalysts can act as proton shuttling agents to alter the energetics and kinetic barriers of proton-coupled electron transfer (PCET) reactions. Example reactions will be drawn from our work on electrochemical CO₂ reduction, N₂ reduction and hydrogen evolution reaction.

References

[1] Ershuai Liu, Jingkun Li, Li Jiao, Huong Thi Thanh Doan, Zeyan Liu, Zipeng Zhao, Yu Huang, K. M. Abraham, Sanjeev Mukerjee, and Qingying Jia, JACS 2019 141 (7), 3232-3239 DOI: 10.1021/jacs.8b13228

[2] Emily E. Barton, David M. Rampulla, and Andrew B. Bocarsly, JACS 2008 130 (20), 6342-6344 DOI: 10.1021/ja0776327