Computational Screening of Doped Graphene Electrodes for Alkaline CO2 Reduction

Verma, Anand Mohan; Honkala, Karoliina; Melander, Marko

doi:10.3389/fenrg.2020.606742

Cited by 13 publications

(8 citation statements)

References 120 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Melander et al studied the reaction free energy of the ETPT mechanism for CO 2 adsorption. However, the neglect of the charge in the *COOH intermediate led to a very large energy input for the PT step . Here, we revised the method by considering the noninteger charge along the whole electrochemical reaction pathway.…”

Section: Computational Methodsmentioning

confidence: 99%

“…γ| e| U SHE is the free energy of electron transfer upon an operating potential scale, and γ is the number of transferred net charge in total along the pathway. Assuming that the electron transfer is independent of the potential, γ can be treated as constant . μ⃗ ads is the built-in dipole moment induced by the chemical adsorption of the intermediate, pointing from the negative charge to the positive one.…”

Section: Computational Methodsmentioning

confidence: 99%

“…However, the neglect of the charge in the *COOH intermediate led to a very large energy input for the PT step. 48 Here, we revised the method by considering the noninteger charge along the whole electrochemical reaction pathway. The decoupled electron−proton transfer steps during CO 2 reduction are shown in eqs 6−9…”

Section: ■ Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Selectivity of Electrochemical CO₂Reduction on Metal Electrodes: The Role of the Surface Oxidized Layer

Chen,

Cavallo,

Huang

2023

ACS Catal.

View full text Add to dashboard Cite

In the past decade, density functional theory (DFT) calculations have been employed to study the mechanism of electrochemical CO 2 reduction reactions. However, the lack of understanding of the CO 2 chemisorption states, proton-coupledelectron-transfer (PCET) steps, and dynamic redox reactions of the electrode surface has limited the reliability of these simulations. The *OCHO and *COOH species are widely recognized as the key intermediates for the formic acid and carbon monoxide production, respectively. However, the comparison between the binding energies of *OCHO and *COOH cannot directly indicate the reaction trends. In this work, we propose that the energy difference between *COOH on the neutral and extra-electron substrates, in the form of [ΔG(*COOH e ) − ΔG(*COOH)], can serve as a descriptor for the electrochemical CO 2 reduction selectivity. In addition, the computational hydrogen electrode (CHE) model is revised by applying the previously studied charged species. The noninteger charge-transfer (NICT) model is used for the calculation of energy profile at a certain potential, which can have a good prediction of the potential-limiting step. The surface oxide of metal electrodes is found to play a key role in modulating the selectivity and improving the electron transfer to CO 2 .

show abstract

Section: Computational Methodsmentioning

confidence: 99%

Section: Computational Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Selectivity of Electrochemical CO₂Reduction on Metal Electrodes: The Role of the Surface Oxidized Layer

Chen,

Cavallo,

Huang

2023

ACS Catal.

View full text Add to dashboard Cite

show abstract

“…The electrosorption of species other than OH as a function of the potential was neglected. This is justified through the recently developed decoupled-CHE model, 84 which uses the electrosorption valency (γ) and the amount of charge transfer (δ e ) from the surface to the adsorbate to model electrosorption free energies as ΔG(U) ads ∝ΔG ads (U = 0) + γδ e . Our calculations show that δ e ≈ 0 for the adsorption of the EOG products (see Supporting Information) and, therefore, their adsorption energies are expected to display only weak dependence on the electrode potential.…”

Section: ■ Computational Detailsmentioning

confidence: 99%

Mechanistic Origins of the pH Dependency in Au-Catalyzed Glycerol Electro-oxidation: Insight from First-Principles Calculations

et al. 2021

Self Cite

View full text Add to dashboard Cite

Electrocatalytic oxidation of glycerol (EOG) is an attractive approach to convert surplus glycerol to value-added products. Experiments have shown that EOG activity and selectivity depend not only on the electrocatalyst but also on the electrode potential, the pH, and the electrolyte. For broadly employed gold (Au) electrocatalysts, experiments have demonstrated high EOG activity under alkaline conditions with glyceric acid as a primary product, whereas under acidic and neutral conditions Au is almost inactive producing only small amounts of dihydroxyacetone. In the present computational work, we have performed an extensive mechanistic study to understand the pH and potential dependency of Au-catalyzed EOG. Our results show that activity and selectivity are controlled by the presence of surface-bound hydroxyl groups. Under alkaline conditions and close to the experimental onset potential, modest OH coverage is preferred according to our constant potential calculations. This indicates that both Au(OH)ads and Au can be active sites and they cooperatively facilitate the thermodynamically and kinetically feasible formation of glyceric acid thus explaining the experimentally observed high activity and selectivity. Under acidic conditions, hydroxide coverage is negligible and the dihydroxyacetone emerges as the favored product. Calculations predict slow reaction kinetics, however, which explains the low activity and selectivity toward dihydroxyacetone reported in experiments. Overall, our findings highlight that computational studies should explicitly account for pH and coverage effects under alkaline conditions for electrocatalytic oxidation reactions to reliably predict electrocatalytic behavior.

show abstract

“…* dipole has similarly been described in terms of a partial charge transfer from the metal to adsorbate. 11,26 In this work, we present a unified mechanistic picture of CO ! R to CO on both these classes of catalysts.…”

Section: Introductionmentioning

confidence: 99%

Unified Mechanistic Understanding of CO2 Reduction to CO on Transition Metal and Single Atom Catalysts

Vijay

Ju²,

Brückner³

et al. 2021

Preprint

View full text Add to dashboard Cite

CO is the simplest product from CO2 electroreduction (CO2R), but the identity and nature of its rate limiting step remains controversial. Here we investigate the activity of both transition metals (TMs) and metal-nitrogen doped carbon catalysts (MNCs), and a present unified mechanistic picture of CO2R to for both these classes of catalysts. By consideration of the electronic structure through a Newns-Andersen model, we find that on MNCs, like TMs, electron transfer to CO2 is facile, such that CO2 (g) adsorption is driven by adsorbate dipole-field interactions. Using density functional theory with explicit consideration of the interfacial field, we find CO2 * adsorption to generally be limiting on TMs, while MNCs can be limited by either CO2* adsorption or by the proton-electron transfer reaction to form COOH*. We evaluate these computed mechanisms against pH-dependent experimental activity measurements on CO2R to CO activity for Au, FeNC, and NiNC. We present a unified activity volcano that, in contrast to previous analyses, includes the decisive CO2* and COOH* binding strengths as well as the critical adsorbate dipole-field interactions. We furthermore show that MNC catalysts are tunable towards higher activity away from transition metal scaling, due to the stabilization of larger dipoles resulting from their discrete and narrow d-states. The analysis suggests two design principles for ideal catalysts: moderate CO2* and COOH* binding strengths as well as large dipoles on the CO2* intermediate. We suggest that these principles can be exploited in materials with similar electronic structure to MNCs, such as supported single-atom catalysts, molecules, and nanoclusters, 2D materials, and ionic compounds towards higher CO2R activity. This work captures the decisive impact of adsorbate dipole-field interactions in CO2R to CO and paves the way for computational-guided design of new catalysts for this reaction.

show abstract

Computational Screening of Doped Graphene Electrodes for Alkaline CO2 Reduction

Cited by 13 publications

References 120 publications

Selectivity of Electrochemical CO₂Reduction on Metal Electrodes: The Role of the Surface Oxidized Layer

Selectivity of Electrochemical CO₂Reduction on Metal Electrodes: The Role of the Surface Oxidized Layer

Mechanistic Origins of the pH Dependency in Au-Catalyzed Glycerol Electro-oxidation: Insight from First-Principles Calculations

Unified Mechanistic Understanding of CO2 Reduction to CO on Transition Metal and Single Atom Catalysts

Contact Info

Product

Resources

About

Computational Screening of Doped Graphene Electrodes for Alkaline CO2 Reduction

Cited by 13 publications

References 120 publications

Selectivity of Electrochemical CO2Reduction on Metal Electrodes: The Role of the Surface Oxidized Layer

Selectivity of Electrochemical CO2Reduction on Metal Electrodes: The Role of the Surface Oxidized Layer

Mechanistic Origins of the pH Dependency in Au-Catalyzed Glycerol Electro-oxidation: Insight from First-Principles Calculations

Unified Mechanistic Understanding of CO2 Reduction to CO on Transition Metal and Single Atom Catalysts

Contact Info

Product

Resources

About

Selectivity of Electrochemical CO₂Reduction on Metal Electrodes: The Role of the Surface Oxidized Layer

Selectivity of Electrochemical CO₂Reduction on Metal Electrodes: The Role of the Surface Oxidized Layer