Implications of coverage-dependent O adsorption for catalytic NO oxidation on the late transition metals

Frey, Kurt; Schmidt, David; Wolverton, Chris; Schneider, William F.

doi:10.1039/c4cy00763h

Cited by 66 publications

(87 citation statements)

References 37 publications

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“…The calculated much lower energy barrier on the Pt(1 1 1) surface for the hydrogenation of MCONE than on the Pd(1 1 1) surface is in agreement with the experimental observation herein that on the Pt/HY [50][51][52] indicate that the free energy barrier for hydrogenation of C@O bonds is higher (i.e., lower rates) on Pd than on Pt surfaces. The lower activity of Pd has been usually linked to the stronger interactions of O with Pd than with Pt [53][54][55]. The stronger interaction of the reactant with the catalyst surface leading to lower rates indicates that Pt, on the activity volcano plot, is closer than Pd to the optimum MAO strength that maximizes hydrogenation.…”

Section: Hydrogenation Of 3-methylcyclohexanone and 3-methylcyclohexementioning

confidence: 97%

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Anaya

Zhang

Tan

et al. 2015

Journal of Catalysis

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a b s t r a c tThe liquid-phase hydroalkylation of m-cresol catalyzed by zeolite catalysts doped with noble metals was investigated at 473 K and 5200 kPa of H 2 . Metals (Pt and Pd) were incorporated in HY (Si/Al = 30) and HMor (Si/Al = 10) zeolites by incipient wetness impregnation. The structural properties of the samples were characterized by NMR, XPS, and BET. Hydroalkylation of m-cresol involves a series of steps that start with the ring saturation to 3-methylcyclohexanone (MCONE), which is the primary product and is further hydrogenated to methylcyclohexanol (MCNOL) on the metal function. This, in turn, is dehydrated on the acid sites to 3-methylcyclohexene, which readily alkylates the unreacted m-cresol to form bicyclic compounds that fall in the desirable fuel range. In these bifunctional catalysts, differences in intrinsic hydrogenation activity of metals play an important role in determining the final selectivity to alkylated products. In fact, the ratio of number of acid sites (n A ) to exposed metal sites (n M ) can be tuned to maximize the selectivity toward bicyclic compounds because this selectivity is determined by the fate of the intermediate 3-methylcyclohexene (MCENE). That is, if the C@C hydrogenation on the metal is fast compared to alkylation on the acid site, the selectivity decreases. However, if the hydrogenation is too slow, the overall product yield decreases. Thus, to optimize the hydroalkylation yield, a delicate metal/acid balance is required. Moreover, in the absence of metal, the zeolite would deactivate very quickly. Therefore, having the metal and acid functions together is also important for extending the catalyst life. Finally, it has been observed that 3D-pore zeolites, such as HY, are preferred over 1D-pore zeolites such as HMor, which sharply diminish the formation of alkylation compounds, despite being more acidic than HY.

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Section: Hydrogenation Of 3-methylcyclohexanone and 3-methylcyclohexementioning

confidence: 97%

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Anaya

Zhang

Tan

et al. 2015

Journal of Catalysis

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“…Recent detailed theoretical study of NO oxidation on Pd and other metals explores the role of oxygen-coverage, cluster sizes, metal-oxygen binding strength, and oxygen dissociation 36 . For Pd, palladium oxide is believed to be active catalyst for NO oxidation 38–40 .…”

Section: Introductionmentioning

confidence: 99%

Single Pd Atoms on θ-Al2O3 (010) Surface do not Catalyze NO Oxidation

Narula

Allard

Moses-DeBusk

et al. 2017

Sci Rep

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New convenient wet-chemistry synthetic routes have made it possible to explore catalytic activities of a variety of single supported atoms, however, the single supported atoms on inert substrates (e.g. alumina) are limited to adatoms and cations of Pt, Pd, and Ru. Previously, we have found that single supported Pt atoms are remarkable NO oxidation catalysts. In contrast, we report that Pd single atoms are completely inactive for NO oxidation. The diffuse reflectance infra-red spectroscopy (DRIFTS) results show the absence of nitrate formation on catalyst. To explain these results, we explored modified Langmuir-Hinshelwood type pathways that have been proposed for oxidation reactions on single supported atom. In the first pathway, we find that there is energy barrier for the release of NO2 which prevent NO oxidation. In the second pathway, our results show that there is no driving force for the formation of O=N-O-O intermediate or nitrate on single supported Pd atoms. The decomposition of nitrate, if formed, is an endothermic event.

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“…kMC has proven its potential in this respect having been successfully applied to a large variety of catalytic systems. [24][25][26][27][28][29][30][31][32][33][34][35][36][37] A recent kMC framework is the graph-theoretical Zacros code of Stamatakis et al 38,39 which is particularly suited for applications in catalysis, since it is able to deal with multidentate species, complex elementary steps (e.g. involving more than two sites in specific geometric arrangements), and reaction barriers changing in the presence of spectator species that exert lateral interactions.…”

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confidence: 99%

A machine learning approach to graph-theoretical cluster expansions of the energy of adsorbate layers

Vignola

Steinmann

Vandegehuchte

et al. 2017

The Journal of Chemical Physics

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_________________________________________The accurate description of the energy of adsorbate layers is crucial for the understanding of chemistry at interfaces. For heterogeneous catalysis not only the interaction of the adsorbate with the surface, but also adsorbate-adsorbate lateral interactions significantly affect activation energies of reactions. Modeling the interactions of adsorbates with the catalyst surface and with each other can be efficiently achieved in the cluster expansion Hamiltonian formalism, which has recently been implemented in a graph-theoretical kinetic Monte Carlo (kMC) scheme to describe multi-dentate species. Automating the development of the cluster expansion Hamiltonians for catalytic systems is challenging and requires the mapping of adsorbate configurations for extended adsorbates onto a graphical lattice. The current work adopts machine learning methods to reach this goal. Clusters are automatically detected based on formalized, but intuitive chemical concepts. The corresponding energy coefficients for the cluster expansion are calculated by an inversion scheme. The potential of this method is demonstrated for the example of ethylene adsorption on Pd (111), for which we propose several expansions, depending on the graphical lattice. It turns out that for this system the best description is obtained as a combination of single molecule patterns and a few coupling terms accounting for lateral interactions. _______________________________________

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Implications of coverage-dependent O adsorption for catalytic NO oxidation on the late transition metals

Abstract: Cluster-expansion-based kinetic model reveals that adsorbate interactions both promote and inhibit NO oxidation on the late transition metals.

Cited by 66 publications

References 37 publications

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Single Pd Atoms on θ-Al2O3 (010) Surface do not Catalyze NO Oxidation

A machine learning approach to graph-theoretical cluster expansions of the energy of adsorbate layers

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