Proton-coupled electron transfer in the electrocatalysis of CO<sub>2</sub> reduction: prediction of sequential vs. concerted pathways using DFT

Göttle, Adrien J.; Koper, Marc T. M.

doi:10.1039/c6sc02984a

Cited by 190 publications

(166 citation statements)

References 57 publications

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“…Here, formic acid with pK a of 3.75 was chosen as the reference species. A very good linear correlation with experimental value was found, which demonstrates that formic acid, despite being the simplest carboxylic acid, is a reliable reference

Δ G_{EX} = Δ G_{AH} - Δ G_{HCOOH} = - italicRT ln K_{a, AH} + italicRT ln K_{a, HCOOH} = ln 10 \cdot italicRT ((), {pK}_{a, AH} - {pK}_{a, HCOOH}) .

{pK}_{a, AH} = \frac{Δ G_{EX}}{ln 10 \cdot italicRT} + {pK}_{a, HCOOH} .

…”

Section: Computational Detailsmentioning

confidence: 53%

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Xiang

Zhang

Gao

et al. 2019

J Raman Spectroscopy

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The pH‐dependent surface‐enhanced Raman spectra of two typical surface sensor molecules p‐mercaptobenzoic acid (PMBA) and p‐mercaptopyridine (PMPY) were simulated by density functional theory calculations. First, the acid dissociation constants and individual surface Raman spectra of PMBA and PMPY were computed and compared with experimental results. It was found that acid dissociation constants calculated by the hybrid implicit‐explicit model and surface‐enhanced Raman scattering (SERS) spectra simulated by the explicit model most closely coincide with experimental results. Then, the pH‐dependent SERS spectra of PMBA and PMPY were obtained by overlaying the SERS of individual acid species and base species multiplied by their molar fractions, which were calculated from the acid dissociation constants. During the deprotonation process of PMBA, the Raman intensity from COOH stretching decreases and the Raman intensity from COO− stretching increases. During the protonation process of PMPY, the ν8a mode undergoes a significant blueshift and the relative Raman intensity of ν7a mode decreases. At last, pH calibration curves of PMBA and PMPY were obtained according to the simulated pH‐dependent Raman spectra, in which the logarithmic value of relative Raman intensity of characteristic peaks varies almost linearly with solution pH.

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Δ G_{EX} = Δ G_{AH} - Δ G_{HCOOH} = - italicRT ln K_{a, AH} + italicRT ln K_{a, HCOOH} = ln 10 \cdot italicRT ((), {pK}_{a, AH} - {pK}_{a, HCOOH}) .

{pK}_{a, AH} = \frac{Δ G_{EX}}{ln 10 \cdot italicRT} + {pK}_{a, HCOOH} .

…”

Section: Computational Detailsmentioning

confidence: 53%

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Xiang

Zhang

Gao

et al. 2019

J Raman Spectroscopy

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“…1). While the comparisons between the sequential and concerted reaction pathways were made in detail for the proton-coupled electron transfer in the electrochemical reduction of CO 2 using cobalt-porphyrin catalysts,25,48 the present study is different from the previous report in that not the H + in the aqueous medium but the H 2 O molecule becomes the proton source to facilitate the CO 2 reduction. Here, it is noteworthy that the [CoP−CO 2 ] -formation reaction (Eq.…”

mentioning

confidence: 63%

“…51 We added two explicit water molecules in order to investigate the effect of the hydrogen bonds to the standard equilibrium potential of the concerted reaction. Positions of the two water molecules are determined based on the previous report 25 Table S4 in the Supporting Information. This agreement is interesting by considering the fact that the pKa values are obtained using completely different methods, i.e., ab initio molecular dynamics simulations, 22 the method based on the isodesmic protonexchange reaction scheme, 25 and our protocol.…”

Section: Resultsmentioning

confidence: 99%

Water Facilitated Electrochemical Reduction of CO₂ on Cobalt-Porphyrin Catalysts

Miyamoto

Asahi

2019

J. Phys. Chem. C

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Cobalt-porphyrin catalyzed reductive decomposition of CO 2 to CO is investigated based on the Koper's water facilitated CO 2 reduction mechanism using simple but accurate protocol based on thermodynamics. In our protocol, accurate predictions of standard redox potentials and free energy differences are achieved by combining strengths of both density functional theory and experimental observations. With the proposed protocol, we found that the proton transfer from H 2 O takes place at −0.80 V vs. RHE at pH=3 through a concerted pathway and, as a result, the key intermediate for the CO generation, i.e., [CoP−COOH]is formed. Since the redox potential of the proton transfer agrees well with experimentally observed CO 2 reduction potential, we successfully clarified that H 2 O plays an important role in the reductive decomposition of CO 2 to CO. This result is valuable not only for understanding the cobalt-porphyrin catalyzed reductive decomposition of CO 2 but also as a guide for the development of new catalysts.

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“…The energetics of this rearrangement provide mechanistic insight into the catalytic role of hydrogenbonding and intramolecular proton transfer in this system. However, the energetics of this rearrangement presents challenges for DFT; although widely used for Co-based systems, [63][64][65][66][67][68][69][70][71][72] DFT can be inaccurate for reaction barriers, particularly those involving multireference character. [73][74][75][76][77] Further, the geometry and strength of hydrogen bonds can be strongly functional dependent.…”

Section: Resultsmentioning

confidence: 99%

Even-handed subsystem selection in projection-based embedding

Welborn

Manby

Miller

2018

The Journal of Chemical Physics

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Projection-based embedding offers a simple framework for embedding correlated wavefunction methods in density functional theory. Partitioning between the correlated wavefunction and density functional subsystems is performed in the space of localized molecular orbitals. However, during a large geometry change -such as a chemical reaction -the nature of these localized molecular orbitals, as well as their partitioning into the two subsystems, can change dramatically. This can lead to unphysical cusps and even discontinuities in the potential energy surface. In this work, we present an even-handed framework for localized orbital partitioning that ensures consistent subsystems across a set of molecular geometries. We illustrate this problem and the even-handed solution with a simple example of an S N 2 reaction. Applications to a nitrogen umbrella flip in a cobalt-based CO 2 reduction catalyst and to the binding of CO to Cu clusters are presented. In both cases, we find that even-handed partitioning enables chemically accurate embedding with modestly-sized embedded regions for systems in which previous partitioning strategies are problematic.

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Proton-coupled electron transfer in the electrocatalysis of CO₂ reduction: prediction of sequential vs. concerted pathways using DFT

Abstract: We provide a complete and computationally detailed picture of the mechanism of the initial stages of the electrocatalytic reduction of CO2 in water catalysed by cobalt porphyrin complexes.

Cited by 190 publications

References 57 publications

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Water Facilitated Electrochemical Reduction of CO₂ on Cobalt-Porphyrin Catalysts

Even-handed subsystem selection in projection-based embedding

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Proton-coupled electron transfer in the electrocatalysis of CO2 reduction: prediction of sequential vs. concerted pathways using DFT

Abstract: We provide a complete and computationally detailed picture of the mechanism of the initial stages of the electrocatalytic reduction of CO2 in water catalysed by cobalt porphyrin complexes.

Cited by 190 publications

References 57 publications

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Simulating pH‐dependent surface‐enhanced Raman spectra by density functional theory calculations

Water Facilitated Electrochemical Reduction of CO2 on Cobalt-Porphyrin Catalysts

Even-handed subsystem selection in projection-based embedding

Contact Info

Product

Resources

About

Proton-coupled electron transfer in the electrocatalysis of CO₂ reduction: prediction of sequential vs. concerted pathways using DFT

Water Facilitated Electrochemical Reduction of CO₂ on Cobalt-Porphyrin Catalysts