Unified mechanistic understanding of CO2 reduction to CO on transition metal and single atom catalysts

Vijay, Sudarshan; Ju, Wen; Brückner, Sven; Tsang, Sze-Chun; Strasser, Peter; Chan, Karen

doi:10.1038/s41929-021-00705-y

Cited by 217 publications

(229 citation statements)

References 74 publications

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“…For the systems studied herein, q ads is always an integer value based on these analyses, reflecting the similarities between different GCC organic acid surface sites and their respective molecular analogues . However, noninteger values of q ads may be present in other systems, ,,− and our approach does not require that q ads be an integer. Note that this assumption of constant q ads is not valid when there is significant hybridization between the electrode surface and the adsorbate near the Fermi level, wherein q ads will depend on the applied potential.…”

Section: Theory and Computational Methodsmentioning

confidence: 96%

Multicapacitor Approach to Interfacial Proton-Coupled Electron Transfer Thermodynamics at Constant Potential

et al. 2021

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Theoretical calculations of interfacial thermodynamics at constant potential enhance understanding of heterogeneous electrocatalytic reactions. Herein, a strategy is devised for computing reaction thermodynamics for electrochemical proton-coupled electron transfer (PCET), a key elementary step in a wide range of electrocatalytic processes. In this approach, Gibbs free energies obtained from constant charge periodic density functional theory calculations are transformed to grand potentials by using a grid-based mapping procedure in conjunction with a multicapacitor model that accounts for constantly charged surface adsorbates. The energetic contribution of the adsorbate capacitor to the grand potential is found to be essential for computing proton-coupled redox potentials at constant potential. This strategy is applied to graphite-conjugated catalysts, wherein organic acids are attached to carbon surfaces through a conductive phenazine bridge. In these systems, PCET occurs at both the phenazine bridges and the organic acids, which can be negatively or positively charged. For a given graphite-conjugated catalyst active site, the charge of the organic acid adsorbate remains virtually constant for the relevant range of electrode potentials. Moreover, the potential-dependent graphite surface charge density, which excludes this adsorbate charge, is consistent across all systems studied. Within this framework, the potential-dependent PCET reaction free energies are independent of cell size, thereby avoiding the need for computationally expensive cell size extrapolation techniques. The proton-coupled redox potentials computed with this strategy are in agreement with experimental data. This computational strategy, as well as the conceptual insights about the impact of charged adsorbates on electrochemical interfaces, is applicable to other materials and processes.

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Section: Theory and Computational Methodsmentioning

confidence: 96%

Multicapacitor Approach to Interfacial Proton-Coupled Electron Transfer Thermodynamics at Constant Potential

et al. 2021

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“…Here, the nearly overlapping TOF‐potential trends of the tested catalysts imply a similar kinetic reaction barrier: the binding energy to the COOH* intermediate. [24] DFT calculations show the trends on various simplified DV Ni−N x ( x =1, 2, 3, 4) motifs, and the Ni(111) facet. Displayed in Figure 4 c, the nitrogen coordination number significantly affects the COOH* binding and leads to distinct theoretical TOF‐potential trend lines (Figure 4 b).…”

Section: Electrochemical Co 2 Rr Activity Evaluati...mentioning

confidence: 99%

Covalent Organic Framework (COF) Derived Ni‐N‐C Catalysts for Electrochemical CO₂ Reduction: Unraveling Fundamental Kinetic and Structural Parameters of the Active Sites

Vijay

et al. 2022

Angew Chem Int Ed

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Electrochemical CO2 reduction is a potential approach to convert CO2 into valuable chemicals using electricity as feedstock. Abundant and affordable catalyst materials are needed to upscale this process in a sustainable manner. Nickel‐nitrogen‐doped carbon (Ni‐N‐C) is an efficient catalyst for CO2 reduction to CO, and the single‐site Ni−Nx motif is believed to be the active site. However, critical metrics for its catalytic activity, such as active site density and intrinsic turnover frequency, so far lack systematic discussion. In this work, we prepared a set of covalent organic framework (COF)‐derived Ni‐N‐C catalysts, for which the Ni−Nx content could be adjusted by the pyrolysis temperature. The combination of high‐angle annular dark‐field scanning transmission electron microscopy and extended X‐ray absorption fine structure evidenced the presence of Ni single‐sites, and quantitative X‐ray photoemission addressed the relation between active site density and turnover frequency.

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“…Recently, an alternative force-based method to compute β was developed by Vijay et al 43 This method involves applying a finite difference approximation to extract the dependence of the energy of a given state to electrochemical potential along the reaction coordinate based on the positions and forces of the atoms involved in the PCET. Additional details regarding the force-based method to compute β are provided in the Supporting Information.…”

Section: The Journal Of Physical Chemistry Lettersmentioning

confidence: 99%

Generalizable Trends in Electrochemical Protonation Barriers

Patel

Vijay

Kastlunger

et al. 2021

J. Phys. Chem. Lett.

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Predicting activation energies for reaction steps is essential for modeling catalytic processes, but accurate barrier simulations often require considerable computational expense, especially for electrochemical reactions. Given the challenges of barrier computations and the growing promise of electrochemical routes for various processes, generalizable energetic trends in electrochemistry can significantly aid in analyzing reaction networks and building microkinetic models. Herein, we employ density functional theory and machine learning nudged elastic band models to simulate electrochemical protonation of *C, *N, and *O monatomic adsorbates from hydronium on a series of transition metal surfaces. We observe a consistent trend of decreasing protonation reaction energies yet increasing activation barriers from *O to *N to *C. Analysis of bond orders and reaction pathways provides insight into the origin of the observed trends in protonation energetics. We hypothesize that these results are relevant for polyatomic adsorbates, which can simplify analysis of reaction mechanisms and inform catalyst design.

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Unified mechanistic understanding of CO2 reduction to CO on transition metal and single atom catalysts

Cited by 217 publications

References 74 publications

Multicapacitor Approach to Interfacial Proton-Coupled Electron Transfer Thermodynamics at Constant Potential

Multicapacitor Approach to Interfacial Proton-Coupled Electron Transfer Thermodynamics at Constant Potential

Covalent Organic Framework (COF) Derived Ni‐N‐C Catalysts for Electrochemical CO₂ Reduction: Unraveling Fundamental Kinetic and Structural Parameters of the Active Sites

Generalizable Trends in Electrochemical Protonation Barriers

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Unified mechanistic understanding of CO2 reduction to CO on transition metal and single atom catalysts

Cited by 217 publications

References 74 publications

Multicapacitor Approach to Interfacial Proton-Coupled Electron Transfer Thermodynamics at Constant Potential

Multicapacitor Approach to Interfacial Proton-Coupled Electron Transfer Thermodynamics at Constant Potential

Covalent Organic Framework (COF) Derived Ni‐N‐C Catalysts for Electrochemical CO2 Reduction: Unraveling Fundamental Kinetic and Structural Parameters of the Active Sites

Generalizable Trends in Electrochemical Protonation Barriers

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Covalent Organic Framework (COF) Derived Ni‐N‐C Catalysts for Electrochemical CO₂ Reduction: Unraveling Fundamental Kinetic and Structural Parameters of the Active Sites