Coverage-Dependent Microkinetics in Heterogeneous Catalysis Powered by the Maximum Rate Analysis

Chen, Zheng; Liu, Zhangyun; Xu, Xin

doi:10.1021/acscatal.1c01997

Cited by 10 publications

(39 citation statements)

References 70 publications

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“…Moreover, the strong reactivity for adsorbates on the screened surfaces indicates very likely adsorbate–adsorbate interactions between adsorbates, which was also reported in previous investigations for HCl oxidation . It makes a greater challenge in rate calculations and also influences the accuracy for the trend prediction. , Therefore, the 2D-RPD provides a general view for the activity change with the varying of descriptors, which helps the understanding of activity trend and reaction mechanisms. However, a more reasonable consideration of coverage-effect in the screening on the RPD is of vital importance for further design of catalysts.…”

Section: Resultssupporting

confidence: 57%

“…43 It makes a greater challenge in rate calculations and also influences the accuracy for the trend prediction. 59,60 Therefore, the 2D-RPD provides a 2e) and coverage-dependent screened points (green, Table S13) based on coverage self-consistent energies at quasi-steady state with the Cl*(p) differential adsorption energy to be 0 on the 2D-RPD. (d) A comparison between theoretically predicted activities (−ΔG RPD ) from either coveragedependent or coverage-independent screened points and the experimental activities as a validation.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Computational Design of Spinel Oxides through Coverage-Dependent Screening on the Reaction Phase Diagram

Guo

Tian

et al. 2022

ACS Catal.

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Binary spinel-type metal oxides provide additional opportunities to achieve various catalytic reactions. However, the complexity of the catalytic reaction network, particularly the one containing lattice O involved steps on oxide surfaces, makes it difficult to parse reliable reaction mechanisms. It further challenges the accurate description of catalytic activity in the computational design of catalysts. Therefore, in this work, the rational design of spinel oxides was set out with all elementary steps considered on either perfect or defect sites with also lattice O involved steps. As a result, 2108 possible reaction pathways were enumerated within a complete reaction network for HCl oxidation as a model reaction. The strategy of energy global optimization was performed to obtain favored mechanisms within all possible pathways, building an “energy level” activity trend, namely, the “reaction phase” diagram (RPD). The activity screening for 18 spinel oxides was conducted by descriptors on the RPD. Taking care of the poisoning effect by chloride on the surface, the coverage-dependent screening was performed to search more reliable candidates on the “energy level” trend. Six spinel oxides were finally selected from the coverage-dependent screening on the RPD, where the theoretical activity trend was validated by experiments. At the end, a rigorous rate calculation was performed by the coverage self-consistent microkinetic modeling on the most active surface (CuCo2O4). The reliability of models and approximations used in the scheme of coverage-dependent screening on the RPD, together with the importance of coverage effect, were discussed.

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Section: Resultssupporting

confidence: 57%

Section: ■ Results and Discussionmentioning

confidence: 99%

Computational Design of Spinel Oxides through Coverage-Dependent Screening on the Reaction Phase Diagram

Guo

Tian

et al. 2022

ACS Catal.

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“…A method that adopts the strategy of separating in advance fast diffusion events and slow reaction events is the recently introduced "extended phenomenological kinetics" (XPK) approach. [182][183][184][185][186][187] This approach is a hybrid between a diffusion-only KMC explicitly taking place on the lattice, which enables the evaluation of the reaction propensities for elementary events, and a subsequent implicit-lattice KMC that evolves the number of species on the surface. Another method that addresses the problem of fast diffusion is the recently introduced fast species redistribution (FSR) method.…”

Section: Treating Event Frequency Disparitymentioning

confidence: 99%

Kinetic Monte Carlo simulations for heterogeneous catalysis: Fundamentals, current status, and challenges

Pineda

Stamatakis

2022

The Journal of Chemical Physics

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Kinetic Monte Carlo (KMC) simulations in combination with first-principles-based calculations are rapidly becoming the gold-standard computational framework for bridging the gap between the wide range of length and time-scales over which heterogeneous catalysis unfolds. First-principles KMC (1p-KMC) simulations provide accurate insights into reactions over surfaces, a vital step towards the rational design of novel catalysts. In this perspective article, we briefly outline basic principles, computational challenges, successful applications, as well as future directions and opportunities of this promising and ever more popular kinetic modeling approach.

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“…It is also worth noting that all of the microkinetic models mentioned in this Account are based on the mean-field approximation. Other formalisms such as kinetic Monte Carlo (KMC) simulations can also be adopted. − The total rates obtained from the microkinetic models are based on the steady-state approximation, which may be different from the experimental kinetics that typically represent an integral over all stationary points of the reactor. Other selected challenges for further development in mcriokentic modeling are summarized here:…”

Section: Perspectives and Conclusionmentioning

confidence: 99%

Achieving Theory–Experiment Parity for Activity and Selectivity in Heterogeneous Catalysis Using Microkinetic Modeling

Xie

Chen

et al. 2022

Acc. Chem. Res.

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Conspectus Microkinetic modeling based on density functional theory (DFT) energies plays an essential role in heterogeneous catalysis because it reveals the fundamental chemistry for catalytic reactions and bridges the microscopic understanding from theoretical calculations and experimental observations. Microkinetic modeling requires building a set of ordinary differential equations (ODEs) based on the calculation results of thermodynamic properties of adsorbates and kinetic parameters for the reaction elementary steps. Solving a microkinetic model can extract information on catalytic chemistry, including critical reaction intermediates, reaction pathways, the surface species distribution, activity, and selectivity, thus providing vital guidelines for altering catalysts. However, the quantitative reliability of traditional microkinetic models is often insufficient to conclusively extrapolate the mechanistic details of complex reaction systems. This can be attributed to several factors, the most important of which is the limitation of obtaining an accurate estimation of the energy inputs via traditional calculation methods. These limitations include the difficulty of using static DFT methods to calculate reaction energies of adsorption/desorption processes, often rate-controlling or selectivity-determining steps, and the inadequate consideration of surface coverage effects. In addition, the robust microkinetic software is rare, which also complicates the resolution of complex catalytic systems. In this Account, we review our recent works toward refining the predictions of microkinetic modeling in heterogeneous catalysis and achieving theory–experiment parity for activity and selectivity. First, we introduce CATKINAS, a microkinetic software developed in our group, and show how it disentangles the problem that traditional microkinetic software has and how it can now be applied to obtain kinetic results for more sophisticated reaction systems. Second, we describe a molecular dynamics method developed recently to obtain the free-energy changes for the adsorption/desorption process to fill in the missing energy inputs. Third, we show that a rigorous consideration of surface coverage effects is pivotal for building more realistic models and obtaining accurate kinetic results. Following a series of studies on acetylene hydrogenation reactions on Pd catalysts, we demonstrate how this new approach can provide an improved quantitative understanding of the mechanism, active site, and intrinsic structural sensitivity. Finally, we conclude with a brief outlook and the remaining challenges in this field.

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Coverage-Dependent Microkinetics in Heterogeneous Catalysis Powered by the Maximum Rate Analysis

Cited by 10 publications

References 70 publications

Computational Design of Spinel Oxides through Coverage-Dependent Screening on the Reaction Phase Diagram

Computational Design of Spinel Oxides through Coverage-Dependent Screening on the Reaction Phase Diagram

Kinetic Monte Carlo simulations for heterogeneous catalysis: Fundamentals, current status, and challenges

Achieving Theory–Experiment Parity for Activity and Selectivity in Heterogeneous Catalysis Using Microkinetic Modeling

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