Degree of rate control approach to computational catalyst screening

Wolcott, Christopher A.; Medford, Andrew J.; Studt, Felix; Campbell, Charles T.

doi:10.1016/j.jcat.2015.07.015

Cited by 119 publications

(187 citation statements)

References 47 publications

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“…If the values of X RC,i are known, then it is possible to estimate how changes in the values of G o † i for these steps would lead to changes in the rate of the overall stoichiometric reaction (12). Specifically, the above expression is integrated starting from a reference catalyst, having a rate r 0 , transition states with Gibbs free energies equal to G o † i,0 , and known values of X RC,i , to a new catalyst with rate r and Gibbs free energies equal to G o † i :…”

Section: Significancementioning

confidence: 99%

“…Using the values of X RC,i estimated above, it is now possible to identify the key transition states in the reaction scheme and then use the expansion of the rate in terms of changes in the Gibbs free energies of these key transition states to identify promising catalytic materials, as described by Campbell and coworkers (12). Optimization of catalyst performance is dictated by the Sabatier principle that the surface should stabilize strongly the key transition states identified from reaction steps with finite values of X RC,i , whereas the surface should not bind adsorbed species too strongly, such that the values of K ads,i lead to values of θ p that are approximately equal to 0.5 for the optimal catalyst (41).…”

Section: Analytical Strategy For Analysis Of Reaction Schemesmentioning

confidence: 99%

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Analysis of reaction schemes using maximum rates of constituent steps

Motagamwala

Dumesic

2016

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

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We show that the steady-state kinetics of a chemical reaction can be analyzed analytically in terms of proposed reaction schemes composed of series of steps with stoichiometric numbers equal to unity by calculating the maximum rates of the constituent steps, r max,i , assuming that all of the remaining steps are quasi-equilibrated. Analytical expressions can be derived in terms of r max,i to calculate degrees of rate control for each step to determine the extent to which each step controls the rate of the overall stoichiometric reaction. The values of r max,i can be used to predict the rate of the overall stoichiometric reaction, making it possible to estimate the observed reaction kinetics. This approach can be used for catalytic reactions to identify transition states and adsorbed species that are important in controlling catalyst performance, such that detailed calculations using electronic structure calculations (e.g., density functional theory) can be carried out for these species, whereas more approximate methods (e.g., scaling relations) are used for the remaining species. This approach to assess the feasibility of proposed reaction schemes is exact for reaction schemes where the stoichiometric coefficients of the constituent steps are equal to unity and the most abundant adsorbed species are in quasi-equilibrium with the gas phase and can be used in an approximate manner to probe the performance of more general reaction schemes, followed by more detailed analyses using full microkinetic models to determine the surface coverages by adsorbed species and the degrees of rate control of the elementary steps.chemical kinetics | catalysis | microkinetics C hemical reactions take place through sequences of elementary steps, and the dynamics of the overall stoichiometric reaction are typically controlled by key steps in this sequence of steps. For example, in the case of a catalytic reaction, the reaction kinetics are controlled by the energetics of the transition states for the rate-controlling steps and by the energetics of species that are abundant on the active sites (i.e., the Gibbs free energies of these transition states and adsorbed species relative to the reactants and products of the overall stoichiometric reaction). However, whereas the observed reaction kinetics are controlled by a limited number of transition states and adsorbed species, it is typically required to carry out detailed microkinetic analyses to identify the nature of these key transition states and adsorbed species. Thus, a general strategy to elucidate how the reaction kinetics are controlled by a proposed reaction mechanism is first to carry out density functional theory (DFT) calculations to determine the thermodynamic properties of all adsorbed species and transition states, and then to build a microkinetic model to determine the surface coverages by all adsorbed species and the forward and reverse rates of all elementary steps for a range of reaction conditions (1-5). Sensitivity analyses are then carried out using this microkineti...

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Section: Significancementioning

confidence: 99%

Section: Analytical Strategy For Analysis Of Reaction Schemesmentioning

confidence: 99%

Analysis of reaction schemes using maximum rates of constituent steps

Motagamwala

Dumesic

2016

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

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“…4−7 In spite of the importance of heterogeneous catalysis, a first-principles method capable of predicting E b with chemical accuracy (errors ≤1 kcal/mol) has not yet been demonstrated. Currently, most calculations targeting such systems use density functional theory (DFT) at the generalized gradient and meta-generalized gradient approximation levels (GGA and meta-GGA, respectively) to compute electronic energies.…”

Section: Introductionmentioning

confidence: 99%

Quantum Monte Carlo Calculations on a Benchmark Molecule–Metal Surface Reaction: H₂ + Cu(111)

Doblhoff-Dier

Meyer

Hoggan

et al. 2017

J. Chem. Theory Comput.

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Accurate modeling of heterogeneous catalysis requires the availability of highly accurate potential energy surfaces. Within density functional theory, these can—unfortunately—depend heavily on the exchange-correlation functional. High-level ab initio calculations, on the other hand, are challenging due to the system size and the metallic character of the metal slab. Here, we present a quantum Monte Carlo (QMC) study for the benchmark system H2 + Cu(111), focusing on the dissociative chemisorption barrier height. These computationally extremely challenging ab initio calculations agree to within 1.6 ± 1.0 kcal/mol with a chemically accurate semiempirical value. Remaining errors, such as time-step errors and locality errors, are analyzed in detail in order to assess the reliability of the results. The benchmark studies presented here are at the cutting edge of what is computationally feasible at the present time. Illustrating not only the achievable accuracy but also the challenges arising within QMC in such a calculation, our study presents a clear picture of where we stand at the moment and which approaches might allow for even more accurate results in the future.

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“…[14][15][16] Rational design of efficient heterogeneous catalysts by quantum-chemical calculations, therefore, is currently an exciting and challenging target for researchers; however, traditional trial-and-error methods for producing new catalysts consume great efforts and time, which is inadequate to meet the demand of rapidly developing catalytic community. [17][18][19][20][21][22] The computational design approach, on the contrary, possesses great advantages and attracted more attention in the recent years. First, computational simulations require only electricity and computers, which is considerably more economical and sustainable than synthesizing and testing candidate catalysts experimentally.…”

Section: Introductionmentioning

confidence: 99%

Theory and applications of surface micro‐kinetics in the rational design of catalysts using density functional theory calculations

Mao

Wang

2017

WIREs Comput Mol Sci

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Rational design of catalysts has long been an important and challenging goal in heterogeneous catalysis. To achieve this target, density functional theory (DFT) calculations and micro‐kinetics are two of the cornerstones. The DFT calculations make it possible to obtain microscopic properties of catalytic systems by computational simulations, and the micro‐kinetic modeling of surface reactions provides a tool to link quantum‐chemical data with macroscopic behaviors of the systems. In this review, we focus on the basic concepts and latest theoretical progresses of strategies for the catalysts design, including Brønsted−Evans−Polanyi relation, the volcano curve, and the activity window. Among the progresses, the theory of chemical potential kinetics in heterogeneous catalysis and its implications on catalysts design, which was developed by our group, are described in detail with extensive derivations. Furthermore, the applications of this method on screening low‐cost counter electrodes for dye‐sensitized solar cells are presented with experimental evidences. WIREs Comput Mol Sci 2017, 7:e1321. doi: 10.1002/wcms.1321 This article is categorized under: Structure and Mechanism > Reaction Mechanisms and Catalysis Theoretical and Physical Chemistry > Reaction Dynamics and Kinetics

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Degree of rate control approach to computational catalyst screening

Cited by 119 publications

References 47 publications

Analysis of reaction schemes using maximum rates of constituent steps

Analysis of reaction schemes using maximum rates of constituent steps

Quantum Monte Carlo Calculations on a Benchmark Molecule–Metal Surface Reaction: H₂ + Cu(111)

Theory and applications of surface micro‐kinetics in the rational design of catalysts using density functional theory calculations

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Degree of rate control approach to computational catalyst screening

Cited by 119 publications

References 47 publications

Analysis of reaction schemes using maximum rates of constituent steps

Analysis of reaction schemes using maximum rates of constituent steps

Quantum Monte Carlo Calculations on a Benchmark Molecule–Metal Surface Reaction: H2 + Cu(111)

Theory and applications of surface micro‐kinetics in the rational design of catalysts using density functional theory calculations

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Product

Resources

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Quantum Monte Carlo Calculations on a Benchmark Molecule–Metal Surface Reaction: H₂ + Cu(111)