Computational-chemical advances in heterogeneous catalysis

Santen, van Ra Rutger

doi:10.1016/1381-1169(95)00161-1

Cited by 10 publications

(4 citation statements)

References 40 publications

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“…These clusters form a compact section of the (111) fcc ideal palladium surface. Small cluster models have proved useful in the study of the adsorption of individual species and have provided accurate descriptions of adsorbate structures, vibrations, and chemisorption energies. − The formaldehyde molecule was fully optimized on both palladium clusters, while simultaneously keeping the Pd−Pd distances fixed at the bulk Pd−Pd value of 2.751 Å . When possible, symmetry was imposed.…”

Section: Methodsmentioning

confidence: 99%

Density Functional Theory Study of the Adsorption of Formaldehyde on Pd₄ and on Pd₄/γ-Al₂O₃ Clusters

Carneiro

Cruz

2008

J. Phys. Chem. A

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B3LYP/LANL2DZ and B3LYP/6-31G(d)-restricted and -unrestricted calculations are employed to calculate energies and adsorption forms of formaldehyde adsorbed on planar and on tetrahedral Pd4 clusters and on a Pd4 cluster supported on Al10O15. Formaldehyde adsorbs on planar Pd4 in the eta(2)(C,O)-di-sigma adsorption mode, while on tetrahedral Pd4, it adsorbs in the eta(2)(C,O)-pi adsorption mode. The adsorption energy on planar Pd4 is -21.4 kcal x mol(-1), whereas for the tetrahedral Pd4 cluster, the adsorption energy is -13.2 kcal x mol(-1). The latter value is close to experimental findings (-12 to -14 kcal x mol(-1)). Adsorption of formaldehyde on Pd4 supported on an Al10O15 cluster leads essentially to the same result as that found for adsorption on the tetrahedral Pd4 cluster. Charge density analysis for the interaction between formaldehyde and the Pd4 clusters indicates strong backdonation in the eta(2) adsorption mode, leading to positive charge on the Pd4 cluster. NBO analysis shows that the highly coordinated octahedral aluminum atoms of Al10O15 donate electron density to the supported Pd4 cluster, while tetrahedral aluminum atoms with lower coordination number have acidic nature and therefore act as electron acceptors.

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Section: Methodsmentioning

confidence: 99%

Density Functional Theory Study of the Adsorption of Formaldehyde on Pd₄ and on Pd₄/γ-Al₂O₃ Clusters

Carneiro

Cruz

2008

J. Phys. Chem. A

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“…where Y (0) , Y (4) , and Y (6) are the regression parameters obtained from the application of kubic harmonic interpolation to any facet-dependent parameter of interest. Here, the kubic harmonic approach specifically estimates the mean-field model parameters for E ads and the multivariable regression parameters for G vib surface (T,n) as a function of adsorbate type and facet.…”

Section: Multifaceted Nanoparticle Modelingmentioning

confidence: 99%

“…Modern heterogeneous catalysis methodologies currently grant researchers the capacity to zoom in to nanoscale levels, investigate, and gain insights that are translatable to the macroscale performance. − These insights help to provide a greater understanding of the activity at the catalyst–reactant interface, and all of this fundamental knowledge helps to design more efficient catalysts. − A major component of such investigations is computational studies; however, computational results still diverge from those obtained experimentally. These deviations are especially noticeable when important results such as adsorption energies, desorption temperatures, measured coverages, vibrational frequencies, etc., are compared when obtained using these two avenues. − Such discrepancies are due to critical knowledge gaps in computational catalysis, with two of the major factors being (1) accurately capturing coverage effects and (2) accounting for multifaceted effects present on catalyst nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Coverage- and Facet-Dependent Multiscale Modeling of O* and H* Adsorption on Pt Catalytic Nanoparticles

Omoniyi,

Hensley

2024

J. Phys. Chem. C

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Within computational heterogeneous catalysis, two critical factors exist�coverage and multifaceted effects�which are challenging to incorporate and contribute to differences between the results obtained from computational and experimental studies. Such disparities exist when significant adsorbate−adsorbate interactions are present, particularly when coupled with computationally limited facet sampling. Here, we designed a study to demonstrate the significance of coverage and facet effects on the predicted coverages for O* and H* on Pt nanoparticles. This is accomplished by employing multiscale modeling techniques using a three-pronged approach consisting of density functional theory (DFT), ab initio phase diagrams, and mean-field microkinetic models. Overall, adsorbate−adsorbate interactions are repulsive and far stronger for O*/Pt than for H*/Pt. For O* on Pt(111), repulsive interactions are both two-and three-body, but on Pt(100) and Pt(110), they are predominantly three-body. Through benchmarks to existing experimental literature, we demonstrate that experimentally observed coverages and desorption temperatures can be accurately estimated by computational models when the adsorbate−adsorbate interactions are included. Finally, by combining microkinetic models at the equilibrium limit with kubic harmonic interpolation, we model the impacts of the treatment of adsorbate−adsorbate interactions on the predicted O* and H* coverages over multifaceted Pt nanoparticles. Omitting adsorbate− adsorbate interactions over Pt nanoparticles leads to an overestimation of equilibrium coverages of the adsorbates (maximum of 0.29 and 0.11 ML for O* and H*, respectively) across a wide range of temperatures and pressures relevant to heterogeneous catalysis. Altogether, our work demonstrates that the inclusion of coverage and facet effects increases the accuracy of computational models for heterogeneous catalysts.

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“…37 In particular, ab initio and density functional theory (DFT) methods employed to EC-MC models have been successful in reproducing bonding properties, 38 describing surface adsorption, [39][40][41][42] diffusion, 43 as well as heterogeneous catalysis by transition metals 44,45 and zeolites. [46][47][48][49][50][51][52][53] The EC-MC method has also been successesful in describing graphene functionalisation 54 and the electronic structures of semiconductors. [55][56][57][58][59][60][61][62] When effects of host environment are accounted-for in the models, effects not previously observed may be resolved.…”

Section: Introductionmentioning

confidence: 99%

Periodic vs. molecular cluster approaches to resolving glass structure and properties: Anorthite a case study

Tian

Mahmoud

Cozza

et al. 2016

Journal of Non-Crystalline Solids

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Periodic and molecular cluster models are presented for anorthite (CaAl 2 Si 2 O 8), a cement forming glass with desirable thermal and mechanical properties also tested in dental applications. Both the crystalline and amorphous structures were characterised by ab initio molecular dynamics and found to be in good agreement with experiment. Additional investigations of the elongation and fracture of the glass were also made. The recovery of material properties signaled the failure of the periodic method to generate acceptable fracture surfaces to model cement forming-sites. Isolated molecular cluster models of anorthite (300 atoms) and hydrated anorthite were therefore investigated with electronic structure methods and showed sound structural matches with the traditional periodic structures. The equilibrated clusters were used to develop cement models, through binding of short acid oligomers to selected Al-centres, simulating the glass-polymer interface. Overall, the anorthite glass structures emerging from periodic and cluster models were in close agreement. Results suggest that bare molecular cluster models represent an alternative avenue for accurately investigating amorphous systems, providing more realistic descriptions of edge and corner sites, as well as as interfaces.

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Computational-chemical advances in heterogeneous catalysis

Abstract: A short overview is presented of current status of computational chemistry with respect to issues in heterogeneous catalysis. Applications to transition-metal-and solid-acid catalysis will be discussed.

Cited by 10 publications

References 40 publications

Density Functional Theory Study of the Adsorption of Formaldehyde on Pd₄ and on Pd₄/γ-Al₂O₃ Clusters

Density Functional Theory Study of the Adsorption of Formaldehyde on Pd₄ and on Pd₄/γ-Al₂O₃ Clusters

Coverage- and Facet-Dependent Multiscale Modeling of O* and H* Adsorption on Pt Catalytic Nanoparticles

Periodic vs. molecular cluster approaches to resolving glass structure and properties: Anorthite a case study

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Computational-chemical advances in heterogeneous catalysis

Abstract: A short overview is presented of current status of computational chemistry with respect to issues in heterogeneous catalysis. Applications to transition-metal-and solid-acid catalysis will be discussed.

Cited by 10 publications

References 40 publications

Density Functional Theory Study of the Adsorption of Formaldehyde on Pd4 and on Pd4/γ-Al2O3 Clusters

Density Functional Theory Study of the Adsorption of Formaldehyde on Pd4 and on Pd4/γ-Al2O3 Clusters

Coverage- and Facet-Dependent Multiscale Modeling of O* and H* Adsorption on Pt Catalytic Nanoparticles

Periodic vs. molecular cluster approaches to resolving glass structure and properties: Anorthite a case study

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Density Functional Theory Study of the Adsorption of Formaldehyde on Pd₄ and on Pd₄/γ-Al₂O₃ Clusters

Density Functional Theory Study of the Adsorption of Formaldehyde on Pd₄ and on Pd₄/γ-Al₂O₃ Clusters