Escaping Scaling Relationships for Water Dissociation at Interfacial Sites of Zirconia-Supported Rh and Pt Clusters

Kauppinen, Minttu M.; Korpelin, Ville; Verma, Anand Mohan; Melander, Marko; Honkala, Karoliina

doi:10.26434/chemrxiv.9761477

Cited by 4 publications

(5 citation statements)

References 41 publications

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“…We compare the result with the case of the Pt(111) surface as we can compare it with other DFT calculations. Our result for the activation energy of H 2 O dissociation on Pt(111) agrees well with Kauppinen et al 10 and Wang and Hammer. 29 On the Pt(111) surface, H 2 O dissociation is an endothermic reaction with an energy of 0.52 eV.…”

Section: Resultssupporting

confidence: 92%

“…9 However, the dissociation of H 2 O to H and OH is still an important step in the water gas shift (WGS) reaction. 10,11 Our main emphasis is the interest to study the reaction mechanism of H 2 O dissociation on the metal surface. A well-known example of the dissociation of H 2 O ad → H ad + OH ad on the metal surface is an intermediate step in the Langmuir− Hinshelwood (LH) process of the CO oxidation reaction.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Study of an almost Barrier-Free Water Dissociation on a Platinum (111) Surface Alloyed with Ruthenium and Molybdenum

Cahyanto

Zulaehah²,

Widanarto

et al. 2021

ACS Omega

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A theoretical study based on density functional theory for H 2 O dissociation on the metal surface of Pt(111) alloyed simultaneously with Ru and Mo was performed. The determination of the minimum energy path using the climbing image nudged elastic band (CI-NEB) method shows that the dissociation reaction of H 2 O with this catalyst requires almost no energy cost. This dissociation reaction is not only kinetically favored but also almost thermodynamically neutral and somewhat exothermic. The electronic structure analysis showed that much more charge was released in Mo and was used to bind the adsorbed hydroxyl (OH ad ). Further analyses of the density of states (DOS) showed that the large number of orbitals that overlap when OH binds to Mo are responsible for the stabilization of the OH-surface bond. The stability of the OH ad fragment on the surface is believed to be a descriptor for the dissociation of H 2 O with an almost spontaneous process.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Theoretical Study of an almost Barrier-Free Water Dissociation on a Platinum (111) Surface Alloyed with Ruthenium and Molybdenum

Cahyanto

Zulaehah²,

Widanarto

et al. 2021

ACS Omega

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“…47 Similar breakdown of scaling relations through different mechanisms has been reported in other catalytic reactions. 45,48…”

Section: Evolving Ensembles Affect Mechanisms Of Catalyzed Reactionsmentioning

confidence: 99%

Ensembles of Metastable States Govern Heterogeneous Catalysis on Dynamic Interfaces

2020

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Heterogeneous catalysis is at the heart of chemical industry. Being able to tune and design efficient catalysts for processes of interest is of an utmost importance, and for this, the molecular-level understanding of heterogeneous catalysts is the first step, and indeed a prime focus of the modern catalysis research. For a long time, a single most thermodynamically stable structure of the catalytic interface attained in reaction conditions had been envisioned as the reactive phase. However, some catalytic interfaces continue to undergo structural dynamics in the steady state, triggered by high temperatures, pressures, and binding and changing reagents. Among particularly dynamic interfaces are such widely-used catalysts as crystalline and amorphous surfaced supporting (sub-)nano metallic clusters. Recently, it became clear that this dynamic fluxionality causes the supported clusters to populate many distinct structural and stoichiometric states in catalytic conditions. Hence, the catalytic interface should be viewed as an evolving statistical ensemble of many (not one) structures. Every member in the ensemble contributes to the properties of the catalyst differently, and in proportion to its probability to be populated. This new notion flips the established paradigm and calls for new theory, modeling approaches, operando measurements, and updated design strategies. The statistical ensemble nature of surface-supported sub-nano cluster catalysts can be exemplified by oxide-supported and adsorbate-covered Pt, Pd, Cu, CuPd clusters, catalytic toward oxidative and non-oxidative dehydrogenation. They have access to a variety of 3D and quasi-2D shapes. The compositions of their thermal ensembles are dependent on the cluster size, leading to size-specific catalytic activities and the famous "every atom counts" phenomenon. The support and adsorbates affect catalyst structures, and state of the reacting species causes the ensemble to change in every reaction intermediate. The most stable member of the ensemble dominates the thermodynamic properties of the corresponding intermediate, whereas the kinetics can be determined by more active but less populated metastable catalyst states, and that suggests that many earlier studies might have overlooked the actual active sites. Both effects depend on the relative timescales of catalyst restructuring and reaction dynamics. The catalyst may routinely operate off-equilibrium. Ensemble phenomena lead to surprising exceptions from established rules of catalysis, such as scaling relations, and Arrhenius behavior. Catalyst deactivation is also an ensemble property, and its extent of mitigation can be predicted through the new paradigm. These findings were enabled by advances in theory, such as global optimization and subsequent utilization of multiple local minima, and pathways sampling, as well as operando catalyst characterization. The fact that the per-site and per-species resolution is needed for the description and predicting of catalyst properties gives theory the central role in ...

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“…In addition, LSR are very well‐developed for metals and alloys where the deviations from the d‐band model are relatively small and the surface orientation and coordination can be approximated via metal coordination scaling 32,41 . Oxides and many other materials have complex electronic structures that need to be considered accurately 118 . However, the LSR relations have lower accuracy when applied in oxides, sulfides, nitrides and in general multicomponent phases where two of the elements have marked differences in electronegativity 43,48,119 .…”

Section: Simplifications Implicit To Automatic Modelingmentioning

confidence: 99%

Dimensionality reduction of complex reaction networks in heterogeneous catalysis: From linear‐scalingrelationships to statistical learning techniques

Pablo‐García

Garcı́a-Muelas

Sabadell-Rendón

et al. 2021

WIREs Comput Mol Sci

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The mechanistic analysis in heterogeneous catalysis is based on listing all elementary steps and evaluating explicitly their energies. To this end, computational models based on Density Functional Theory have become a standard to estimate the information needed in mechanistic studies. Typically, either the minimum energy paths or those with the smaller span are summarized in reaction profiles. Such simplifications gather a lot of information, although further dimensionality reduction is required to obtain the most relevant descriptors of catalytic activity and generate the so‐called volcano plots. The selection of descriptors has been traditionally based on simple intermediates, such as central atoms in small molecules (as C in CH4), which have good thermodynamic correlations to other fragments containing them. Yet, in emerging processes (recent studies), the number of intermediates involved increase, configurational effects and lateral interactions become significant, and complex materials with low symmetry are employed, thus the simple rules encapsulated in linear scaling relationships lose their predictive power due to error accumulation. At the same time, large datasets generated for the intermediates call for statistical analysis and thus these techniques are being leveraged to chemical systems, particularly to reduce their dimensionality. This article is categorized under: Structure and Mechanism > Reaction Mechanisms and Catalysis Structure and Mechanism > Computational Materials Science Electronic Structure Theory > Ab Initio Electronic Structure Methods

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Escaping Scaling Relationships for Water Dissociation at Interfacial Sites of Zirconia-Supported Rh and Pt Clusters

Cited by 4 publications

References 41 publications

Theoretical Study of an almost Barrier-Free Water Dissociation on a Platinum (111) Surface Alloyed with Ruthenium and Molybdenum

Theoretical Study of an almost Barrier-Free Water Dissociation on a Platinum (111) Surface Alloyed with Ruthenium and Molybdenum

Ensembles of Metastable States Govern Heterogeneous Catalysis on Dynamic Interfaces

Dimensionality reduction of complex reaction networks in heterogeneous catalysis: From linear‐scalingrelationships to statistical learning techniques

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