Modeling the Electrochemical Hydrogen Oxidation and Evolution Reactions on the Basis of Density Functional Theory Calculations

Skúlason, Egill; Tripković, Vladimir; Björketun, Mårten E.; Guðmundsdóttir, Sigríður; Karlberg, Gustav; Rossmeisl, Jan; Bligaard, Thomas; Jónsson, Hannes; Nørskov, Jens K.

doi:10.1021/jp110913n

Cited by 233 publications

(351 citation statements)

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“…Here, we conclude that electrode charges between −3 and +1 correspond to the the electrochemically interesting potential region from −1.5 to +0.5 V vs SHE, see Figure S2. 15 …”

Section: Evaluating the Accuracy Of The Electrochemical Model At Charmentioning

confidence: 99%

“…Skúlason et al 15 have calculated the activation energy of the Tafel reaction on Pt(111) -the rate-determining step of HER on platinum -at several electrode potentials. According to their results, the reaction barrier is approximately 0.8 eV at U = 0 V and begins rapidly decreasing to-wards zero at U = −0.25 V. Comparing the rate-determining step barriers, we find that the studied CNT is less active towards HER than Pt owing to the 0.3 eV larger activation energy at U = 0 V, given the similarities in computational setups.…”

Section: Standard Free Energy Diagrammentioning

confidence: 99%

“…To explore the effects of hydrogen coverage, we have first computed hydrogen adsorption energies By virtue of the Brønsted-Evans-Polanyi (BEP) relationship, 15 configurations with more endothermic hydrogen adsorption energies should be more reactive towards the Heyrovsky and Tafel reactions than the clean nanotubes, because an increase in adsorption energy translates into a weaker C − H bond. The converse should hold for the Volmer reaction.…”

Section: Effects Of Hydrogen Coveragementioning

confidence: 99%

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Ab Initio Electrochemistry: Exploring the Hydrogen Evolution Reaction on Carbon Nanotubes

Holmberg

Laasonen

2015

J. Phys. Chem. C

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Density functional theory (DFT) was employed to investigate the hydrogen evolution reaction (HER) on pristine and nitrogen doped carbon nanotubes (CNTs) in acidic solution. As the reaction is an electrocatalytic surface reaction, an accurate description of HER requires performing simulations under constant electrode potential conditions. To this end, we examined HER at several electrode charges allowing us to determine grand canonical activation energies as a continuous function of electrode potential. By studying the elementary steps of HER -the Volmer, Tafel and Heyrovsky reactions -and by considering hydrogen coverage effects, we found that the Volmer-Heyrovsky mechanism is the predominant HER mechanism on CNTs with the Heyrovsky step being rate-determining. Our results indicated that CNTs are electrochemically active towards HER, which seen as a decrease in activation energies with growing electrode potential, but that the activity is lower than on platinum matching experimental data.Substitutional nitrogen doping did not improve HER activity, and further research is required to determine which nitrogen configurations contribute to the enhanced catalytic activity observed for experimental NCNTs.

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“…Here, we conclude that electrode charges between −3 and +1 correspond to the the electrochemically interesting potential region from −1.5 to +0.5 V vs SHE, see Figure S2. 15 …”

Section: Evaluating the Accuracy Of The Electrochemical Model At Charmentioning

confidence: 99%

Section: Standard Free Energy Diagrammentioning

confidence: 99%

Section: Effects Of Hydrogen Coveragementioning

confidence: 99%

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Ab Initio Electrochemistry: Exploring the Hydrogen Evolution Reaction on Carbon Nanotubes

Holmberg

Laasonen

2015

J. Phys. Chem. C

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“…181,190 It has also been used extensively to study surface catalytic reactions, particularly in the context of descriptor-based optimization and highthroughput screening of candidate water oxidation and proton reduction electrocatalysts. [191][192][193][194][195] Moreover, there are several methods available that can use DFT-derived energetics to directly compute reaction barriers and extract free energy surfaces. These include the nudged elastic band (NEB) 196 and metadynamics approaches, 197 which have found extensive usage in investigating water redox and dissociation reactions on photocatalyst and photoelectrode materials.…”

Section: Dft and Ground-state Techniquesmentioning

confidence: 99%

Methods of photoelectrode characterization with high spatial and temporal resolution

Esposito

Baxter

John

et al. 2015

Energy Environ. Sci.

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“…These microscopic processes are difficult to probe experimentally (15), so atomistic simulation has played an important role in revealing their molecular-level details. Simulations based on stateof-the-art quantum chemical methods reveal important information about the structure and energetics of these systems; however, without additional importance sampling or embedding, they are too computationally demanding to characterize collective room-temperature dynamics (16)(17)(18)(19). Classical simulations overcome this limitation by treating some interactions empirically, thereby enabling the characterization of the equilibrium dynamics of extended molecular systems.…”

mentioning

confidence: 99%

Microscopic dynamics of charge separation at the aqueous electrochemical interface

Kattirtzi

Limmer

Willard

2017

Proc. Natl. Acad. Sci. U.S.A.

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We have used molecular simulation and methods of importance sampling to study the thermodynamics and kinetics of ionic charge separation at a liquid water-metal interface. We have considered this process using canonical examples of two different classes of ions: a simple alkali-halide pair, Na + I − , or classical ions, and the products of water autoionization, H 3 O + OH − , or water ions. We find that for both ion classes, the microscopic mechanism of charge separation, including water's collective role in the process, is conserved between the bulk liquid and the electrode interface. However, the thermodynamic and kinetic details of the process differ between these two environments in a way that depends on ion type. In the case of the classical ion pairs, a higher free-energy barrier to charge separation and a smaller flux over that barrier at the interface result in a rate of dissociation that is 40 times slower relative to the bulk. For water ions, a slightly higher free-energy barrier is offset by a higher flux over the barrier from longer lived hydrogen-bonding patterns at the interface, resulting in a rate of association that is similar both at and away from the interface. We find that these differences in rates and stabilities of charge separation are due to the altered ability of water to solvate and reorganize in the vicinity of the metal interface.chemical kinetics | catalysis | surface science | ion pairing I n aqueous solution, the association or dissociation of oppositely charged ions requires the collective rearrangement of surrounding water molecules (1, 2), which solvate bound ion pairs differently than individual ions (3-6). The solvent fluctuations that enable these collective rearrangements drive the dynamics of ion pairing and unpairing and therefore play a fundamental role in many chemical reactions. Near the surface of an electrode, these collective solvent fluctuations can differ significantly from that of the bulk liquid (7,8), and these differences can affect the rates and mechanisms of aqueous electrochemical reactions. In this work, we use molecular simulation to investigate the microscopic processes of aqueous ion pairing when it takes place near, but not in direct contact with, an extended metallic electrode. We identify the specific effects of the electrode interface by comparing our results to those generated in the environment of the bulk liquid. We find that the presence of an electrode has little effect on the mechanistic details of ionic charge separation, but can significantly influence the thermodynamics and kinetics of the process. We highlight that this influence is different for simple monovalent salts like Na + and I − , whose transport is limited by the mobility of an aqueous solvation shell (9), than it is for water ions, like H3O + and OH − , whose transport is limited by the concerted hopping of protons along hydrogen-bonding chains (10). This fundamental difference is controlled by the microscopic details of electrode-water interactions and thus has implications for...

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Modeling the Electrochemical Hydrogen Oxidation and Evolution Reactions on the Basis of Density Functional Theory Calculations

Cited by 233 publications

References 0 publications

Ab Initio Electrochemistry: Exploring the Hydrogen Evolution Reaction on Carbon Nanotubes

Ab Initio Electrochemistry: Exploring the Hydrogen Evolution Reaction on Carbon Nanotubes

Methods of photoelectrode characterization with high spatial and temporal resolution

Microscopic dynamics of charge separation at the aqueous electrochemical interface

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