On the Role of the Interfacial Capacitance in Grand-Canonical Simulations of Electrocatalysis

Common models of the electrochemical interface suggest that the potential response of electron transfer energetics scales linearly with the interfacial capacitance.

By Oschinski, Reuter, Hörmann +1ACS electrochemistry.Oct 19, 2026

Score████░░░░░░4.3

VerdictWorth a reader's time today.

Read the original

Abstract

Abstract Common models of the electrochemical interface suggest that the potential response of electron transfer energetics scales linearly with the interfacial capacitance. However, grand-canonical simulations of electrocatalytic adsorption energies, and their dependence on the applied potential, remain remarkably similar when the interface is described by a bare implicit solvent or by a complete water layer, even though these setups change the interfacial capacitance by up to a factor of 3. Herein, we address this conundrum using constant-potential implicit-solvent simulations of the reductive electrosorption of CO2 and Na+ on Au(111). We manually tune the interfacial capacitance over more than an order of magnitude by independently varying the dielectric constant and the solvent cavity size. We show that adsorption energetics can vary drastically despite equal interfacial capacitances; while changes in the bulk dielectric constant lead to a behavior consistent with the classical predictions, reaction energetics are more robust against capacitance variations arising from the size and shape of the implicit solvent cavity. We rationalize the behavior based on the coupled interplay between the interfacial capacitance, the adsorption-induced shift in the potential of zero charge, and a local capacitance mismatch between the clean and adsorbate-covered surface. These contributions can partially compensate, rationalizing the observed insensitivity to the interfacial description while clarifying when simplified models succeed or fail.

Hedda Oschinski, Karsten Reuter, N. Hörmann, Georg Kastlunger

The editor's rubric

Heuristic review

Leverage3 / 5: A method or resource many groups across the field will adopt within a year.; 16% of this desk’s rubric
Magnitude3 / 5: Large gain: roughly 2x, or a clear new state of the art on a hard, unsaturated problem.; 20% of this desk’s rubric
Evidence3 / 5: Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data.; 20% of this desk’s rubric
Novelty2 / 5: A new combination of known ideas.; 10% of this desk’s rubric
Trajectory3 / 5: A clear path to scale.; 14% of this desk’s rubric
Stakes2 / 5: Benefits a professional community (practitioners, clinicians, engineers).; 20% of this desk’s rubric

Dimension	Level	Weight	What that level means
Leverage	███░░ 3	16%	A method or resource many groups across the field will adopt within a year.
Magnitude	███░░ 3	20%	Large gain: roughly 2x, or a clear new state of the art on a hard, unsaturated problem.
Evidence	███░░ 3	20%	Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data.
Novelty	██░░░ 2	10%	A new combination of known ideas.
Trajectory	███░░ 3	14%	A clear path to scale.
Stakes	██░░░ 2	20%	Benefits a professional community (practitioners, clinicians, engineers).

Editor’s rationale

Heuristic triage from title and abstract text only, not a reading of the paper. Cues found: method (we report); gains (orders of magnitude); verification (independent replication); scale (scalable, orders of magnitude); stakes (climate).

How the score was computed

rank-2026-10-18

Score████░░░░░░4.3

Score = 10 × (75% × adjusted merit / 10 + 15% × attention + 10% × freshness)

Desks place stronger verdicts first, then use this score to order work within the same verdict.

Merit: 5.4 / 10; Weighted rubric, evidence-gated.
Adjusted merit: 4.6 / 10; Shrunk toward the desk prior by editor confidence (42%).
Attention: 0%; Citations, upvotes, points, mentions.
Freshness: 85%; Half-life decay since publication.

Citations0 (reference 15, via openalex, Oct 21, 2026, 07:29 UTC)

The record

Reviewed by heuristic-v7 on Oct 21, 2026, 07:29 UTC. Paper type: method.
Categories: Electrocatalysts for Energy Conversion, CO2 Reduction Techniques and Catalysts, Advanced Chemical Physics Studies, Renewable Energy, Sustainability and the Environment, Energy
BRIEF, No.2 in the Climate & Energy edition of October 21, 2026.