Water structures on acidic zeolites and their roles in catalysis

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(6), P. 3065 - 3095

Published: Jan. 1, 2024

The local reaction environment of catalytic active sites can be manipulated to modify the kinetics and thermodynamic properties heterogeneous catalysis. Because unique physical-chemical nature water, heterogeneously catalyzed reactions involving specific interactions between water molecules on catalysts exhibit distinct outcomes that are different from those performed in absence water. Zeolitic materials being applied with presence for chemical industry our transition sustainable energy. Mechanistic investigation in-depth understanding about behaviors roles essentially required zeolite chemistry In this review, we focus discussions structures adsorbed/stabilized Brønsted Lewis acidic zeolites based experimental observations as well theoretical calculation results. unveiled functions determining efficacy zeolite-catalyzed have been overviewed strategies frequently developed enhancing stabilization highlighted. Recent advancement will contribute development innovative rationalization performances terms activity, selectivity stability vapor or condensed aqueous phase.

Language: Английский

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Confined hot-pressurized water in Brønsted-acidic beta zeolite speeds up the O demethylation of guaiacol

Nature Catalysis, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 9, 2025

Language: Английский

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Machine learning-driven molecular dynamics unveils a bulk phase transformation driving ammonia synthesis on barium hydride

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: March 12, 2025

The modern view of industrial heterogeneous catalysis is evolving from the traditional static paradigm where catalyst merely provides active sites, to that a functional material in which dynamics plays crucial role. Using machine learning-driven molecular simulations, we confirm this picture for ammonia synthesis catalysed by BaH2. Recent experiments show system acts as highly efficient catalyst, but only when exposed first N2 and then H2 chemical looping process. Our simulations reveal N2, BaH2 undergoes profound change, transforming into superionic mixed compound, BaH2−2x(NH)x, characterized high mobility both hydrides imides. This transformation not limited surface involves entire catalyst. When compound second step process, readily formed released, process greatly facilitated ionic mobility. Once all nitrogen are hydrogenated, reverts its initial state, ready next cycle. microscopic analysis underlines dynamic nature does serve platform reactions, rather it entity evolves under reaction conditions. shifting paradigm. Here, authors reactions during synthesis,

Language: Английский

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The role of dynamics in heterogeneous catalysis: Surface diffusivity and N ₂ decomposition on Fe(111)

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(50)

Published: Dec. 7, 2023

Dynamics has long been recognized to play an important role in heterogeneous catalytic processes. However, until recently, it impossible study their dynamical behavior at industry-relevant temperatures. Using a combination of machine learning potentials and advanced simulation techniques, we investigate the cleavage N 2 triple bond on Fe(111) surface. We find that low temperatures our results agree with well-established picture. if increase temperature reach operando conditions, surface undergoes global change step structure is destabilized. The sites, traditionally associated this surface, appear disappear continuously. Our simulations illuminate danger extrapolating low-temperature conditions indicate activity can only be inferred from calculations take dynamics fully into account. More than that, they show transition highly fluctuating interfacial environment drives process.

Language: Английский

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Nature of molybdenum carbide surfaces for catalytic hydrogen dissociation using machine-learned potentials: an ensemble-averaged perspective

Catalysis Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Unique surface chemistries of molybdenum carbide phases for H 2 dissociation with MLIP-based reactive molecular dynamics.

Language: Английский

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Innovations in Catalytic Understanding: A Journey through Advanced Characterization

Materials Today Catalysis, Journal Year: 2024, Volume and Issue: unknown, P. 100061 - 100061

Published: Sept. 1, 2024

Language: Английский

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How Dynamics Changes Ammonia Cracking on Iron Surfaces

ACS Catalysis, Journal Year: 2024, Volume and Issue: unknown, P. 14652 - 14664

Published: Sept. 18, 2024

Language: Английский

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The use of collective variables and enhanced sampling in the simulations of existing and emerging microporous materials

Nanoscale, Journal Year: 2024, Volume and Issue: 16(19), P. 9186 - 9196

Published: Jan. 1, 2024

This review summarizes how enhanced sampling methods are used to investigate the complex properties of microporous materials.

Language: Английский

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Impact of Point Defects, External Surfaces Sites, and Si/Al Ratio on Al–O Bonds Hydrolysis Kinetics at the Initiation of Faujasite Dealumination

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(3), P. 1639 - 1652

Published: Jan. 17, 2024

Faujasite is one of the most industrially employed zeolite material, mainly for catalytic applications. Its properties are dependent on its pore network, which can be tuned by dealumination upon steaming. Previous theoretical studies subject based density functional theory identified plausible mechanisms simple bulk structures faujasite, but to gain a more complete understanding dealumination, and able compare experimental situations, must performed realistic complex systems. In this article, we identify intermediates transition states first Al–O bond hydrolysis initiating in faujasite various Si/Al ratios, presence silanol nests defects, at external surface faujasite. We find that breaking made easier from kinetic perspective some sites considering water adsorbed state as reference. Moreover, defects decrease ratio also lower free energy barriers necessary dealuminate. These trends less clear when apparent barrier, desorbed has been taken Subtle local effects enter into play explaining barrier rankings, including participation hydrogen network strengthening outermost zeolite, significantly stabilizes highest cases. bonds make Brønsted–Evans–Polanyi relationships blurrier than sites, suggesting stabilization need explicitly considered.

Language: Английский

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Data-efficient modeling of catalytic reactions via enhanced sampling and on-the-fly learning of machine learning potentials

Published: June 6, 2024

Simulating catalytic reactivity under operative conditions poses a significant challenge due to the dynamic nature of catalysts and high computational cost electronic structure calculations. Machine learning potentials offer promising avenue simulate dynamics at fraction cost, but they require datasets containing all relevant configurations, particularly reactive ones. Here we present scheme construct in data-efficient manner. This is achieved by combining enhanced sampling methods first with Gaussian processes discover transition paths then graph neural networks obtain uniformly accurate description. The necessary configurations are extracted via an active procedure based on local environment uncertainty. We validated our approach studying several reactions related decomposition ammonia iron-cobalt alloy catalysts. Our proved efficient, requiring only ~1,000 DFT calculations per reaction, robust, from different accessible pathways. Using this potential, calculated free energy profiles characterized reaction mechanisms, showing ability provide microscopic insights into complex conditions.

Language: Английский

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