Can the local electric field be a descriptor of catalytic activity? A case study on chorismate mutase

Siddiqui, Shakir Ali; Dubey, Kshatresh Dutta

doi:10.1039/d1cp03978d

Cited by 45 publications

(32 citation statements)

References 65 publications

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“…More broadly, thin double layers yield steeper potential gradients as applied potentials are screened within short distances, and the magnitude of the local potential gradient is key in determining electrochemical reaction rates. ,, In strongly screening cases, large potential gradients will enhance reactivity by creating polarized environments that require less energy for bonds to bend or break. Similar themes of electric field gradients enhancing reactivity are found in biology, where potential gradients in enzyme active sites orient and break chemical bonds or stabilize important reaction intermediates. − …”

Section: Discussionmentioning

confidence: 99%

Tuning Ionic Screening To Accelerate Electrochemical CO₂ Reduction in Ionic Liquid Electrolytes

2022

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Electric double layer formation often governs the rate and selectivity of CO2 electrochemical reduction. Ionic correlations critically define double layer properties that are essential to electrocatalytic performance, including capacitance and localization of potential gradients. However, the influence of ionic correlations on CO2 electroreduction remains unexplored. Here, we use electrochemical conversion of CO2 to CO in ionic liquid-based electrolytes to investigate how the emergence of ionic correlations with increasing ion concentration influences reaction rates and selectivity. Remarkably, we find substantial acceleration of potential-dependent CO2 reduction rates and enhancement of faradaic efficiency to CO at intermediate concentrations of 0.9 M ionic liquid in acetonitrile, a concentration regime that has not been studied previously. We find that onset potentials for CO2 reduction remain relatively unchanged at −2.01 V vs Ag/Ag+ from 0.025 M up to 1.1 M and increase to −2.04 V vs Ag/Ag+ in the limit of neat ionic liquids. Hence, the acceleration of CO2 reduction we observe originates from the amplification of potential-dependent driving forces, as opposed to changes in onset potential. Importantly, our findings are general across cocatalytic and noncatalytic ions. We propose that concentrations of maximum reactivity correspond to conditions where electric double layers exhibit the strongest screening, which would localize electric fields to stabilize polar intermediates. Our study demonstrates that tuning bulk electrostatic screening lengths via modulation of ionic clustering provides a general approach to accelerating both inner-sphere and outer-sphere electrochemical reactions.

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Section: Discussionmentioning

confidence: 99%

Tuning Ionic Screening To Accelerate Electrochemical CO₂ Reduction in Ionic Liquid Electrolytes

2022

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“…Similar themes of electric field gradients enhancing reactivity are found in biology, where gradients in enzymes orient and break chemical bonds, or stabilize reaction intermediates. [59][60][61][62] In CO 2 electroreduction, a key intermediate is a bent negative radical form of CO 2 with a permanent dipole, which is highly unstable and requires breaking double bonds.…”

Section: Resultsmentioning

confidence: 99%

Tuning Ionic Screening to Accelerate Electrochemical CO2 Reduction in Ionic Liquid Electrolytes

Liu

Guo

Gebbie

2022

Preprint

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Electric double layer formation often governs the rate and selectivity of CO2 electrochemical reduction. Ionic correlations critically define double layer properties that are essential to electrocatalytic performance, including capacitance and localization of potential gradients. However, the influence of ionic correlations on CO2 electro-reduction remains unexplored. Here, we use electrochemical conversion of CO2 to CO in ionic liquid-based electrolytes to investigate how the emergence of ionic correlations with increasing ion concentration influences reaction rates and selectivity. Remarkably, we find substantial acceleration of potential-dependent CO2 reduction rates and notable enhancement of faradaic efficiency to CO at intermediate concentrations of 0.9 M ionic liquid in acetonitrile, a concentration regime that has not been studied previously. We find that onset potentials for CO2 reduction remain relatively unchanged at -2.01 V vs. Ag/Ag+ from 0.025 M up to 1.1 M and increase to -2.04 V vs. Ag/Ag+ in the limit of neat ionic liquids. Hence, the acceleration of CO2 reduction we observe originates from the amplification of potential-dependent driving forces, as opposed to changes in onset potential. Importantly, our findings are general across co-catalytic and non-catalytic ions. We propose that concentrations of maximum reactivity correspond to conditions where electric double layers exhibit the strongest screening, which would localize electric fields to stabilize polar intermediates. Our study demonstrates that tuning bulk electrostatic screening lengths via modulation of ionic clustering provides a general approach to accelerating both inner sphere and outer sphere electrochemical reactions.

show abstract

“…More broadly, thin double layers yield steeper potential gradients as applied potentials are screened within short distances, and the magnitude of the local potential gradient is key in determining electrochemical reaction rates. 43,59,60 In strongly-screening cases, large potential gradients will enhance reactivity by creating polarized environments that require less energy for bonds to bend or break. Similar themes of electric field gradients enhancing reactivity are found in biology, where potential gradients in enzyme active sites orient and break chemical bonds or stabilize important reaction intermediates.…”

Section: Discussionmentioning

confidence: 99%

“…Similar themes of electric field gradients enhancing reactivity are found in biology, where potential gradients in enzyme active sites orient and break chemical bonds or stabilize important reaction intermediates. [59][60][61][62] In CO2 electroreduction, a key intermediate is CO2 •-, an unstable and bent negative radical with a permanent dipole. Therefore, a compact and strongly-screening double layer achieved at intermediate concentrations would more effectively stabilize CO2 •-, leading to the maximum rate of CO2 electroreduction.…”

Section: Discussionmentioning

confidence: 99%

Tuning Ionic Screening to Accelerate Electrochemical CO2 Reduction in Ionic Liquid Electrolytes

Liu

Guo

Gebbie

2022

Preprint

View full text Add to dashboard Cite

Electric double layer formation often governs the rate and selectivity of CO2 electrochemical reduction. Ionic correlations critically define double layer properties that are essential to electrocatalytic performance, including capacitance and localization of potential gradients. However, the influence of ionic correlations on CO2 electro-reduction remains unexplored. Here, we use electrochemical conversion of CO2 to CO in ionic liquid-based electrolytes to investigate how the emergence of ionic correlations with increasing ion concentration influences reaction rates and selectivity. Remarkably, we find substantial acceleration of potential-dependent CO2 reduction rates and notable enhancement of faradaic efficiency to CO at intermediate concentrations of 0.9 M ionic liquid in acetonitrile, a concentration regime that has not been studied previously. We find that onset potentials for CO2 reduction remain relatively unchanged at -2.01 V vs. Ag/Ag+ from 0.025 M up to 1.1 M and increase to -2.04 V vs. Ag/Ag+ in the limit of neat ionic liquids. Hence, the acceleration of CO2 reduction we observe originates from the amplification of potential-dependent driving forces, as opposed to changes in onset potential. Importantly, our findings are general across co-catalytic and non-catalytic ions. We propose that concentrations of maximum reactivity correspond to conditions where electric double layers exhibit the strongest screening, which would localize electric fields to stabilize polar intermediates. Our study demonstrates that tuning bulk electrostatic screening lengths via modulation of ionic clustering provides a general approach to accelerating both inner sphere and outer sphere electrochemical reactions.

show abstract

Can the local electric field be a descriptor of catalytic activity? A case study on chorismate mutase

Abstract: The current theoretical perception of enzymatic activity is highly reliant on the determination of activation energy of the reactions which is often calculated using a computational demanding quantum mechanical calculation....

Cited by 45 publications

References 65 publications

Tuning Ionic Screening To Accelerate Electrochemical CO₂ Reduction in Ionic Liquid Electrolytes

Tuning Ionic Screening To Accelerate Electrochemical CO₂ Reduction in Ionic Liquid Electrolytes

Tuning Ionic Screening to Accelerate Electrochemical CO2 Reduction in Ionic Liquid Electrolytes

Tuning Ionic Screening to Accelerate Electrochemical CO2 Reduction in Ionic Liquid Electrolytes

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Can the local electric field be a descriptor of catalytic activity? A case study on chorismate mutase

Abstract: The current theoretical perception of enzymatic activity is highly reliant on the determination of activation energy of the reactions which is often calculated using a computational demanding quantum mechanical calculation....

Cited by 45 publications

References 65 publications

Tuning Ionic Screening To Accelerate Electrochemical CO2 Reduction in Ionic Liquid Electrolytes

Tuning Ionic Screening To Accelerate Electrochemical CO2 Reduction in Ionic Liquid Electrolytes

Tuning Ionic Screening to Accelerate Electrochemical CO2 Reduction in Ionic Liquid Electrolytes

Tuning Ionic Screening to Accelerate Electrochemical CO2 Reduction in Ionic Liquid Electrolytes

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Tuning Ionic Screening To Accelerate Electrochemical CO₂ Reduction in Ionic Liquid Electrolytes

Tuning Ionic Screening To Accelerate Electrochemical CO₂ Reduction in Ionic Liquid Electrolytes