A5081205836- Zeolite Catalysis and Synthesis
- Catalytic Processes in Materials Science
- Advanced Chemical Physics Studies
- Nanocluster Synthesis and Applications
- Advanced NMR Techniques and Applications
- nanoparticles nucleation surface interactions
- Machine Learning in Materials Science
- Mesoporous Materials and Catalysis
- Catalysis and Oxidation Reactions
- Advanced Data Processing Techniques
- Electrocatalysts for Energy Conversion
- Chemical Synthesis and Characterization
- Neural Networks and Applications
- Metal-Organic Frameworks: Synthesis and Applications
- NMR spectroscopy and applications
- Copper-based nanomaterials and applications
- Spectroscopy and Quantum Chemical Studies
- Catalysts for Methane Reforming
- X-ray Diffraction in Crystallography
- Molecular spectroscopy and chirality
- Nanomaterials for catalytic reactions
- Gold and Silver Nanoparticles Synthesis and Applications
- Quantum Dots Synthesis And Properties
- Surface Chemistry and Catalysis
- Advanced Photocatalysis Techniques
Charles University
2018-2024
Chalmers University of Technology
2014-2017
University of Birmingham
2012-2014
Water oxidation is a key catalytic step for electrical fuel generation. Recently, significant progress has been made in synthesizing electrocatalytic materials with reduced overpotentials and increased turnover rates, both parameters enabling commercial use electrolysis or solar to fuels applications. The complexity of the water reaction makes understanding site critical improving process. Here we study alkaline conditions using size-selected clusters Pd probe relationship between cluster...
Aluminosilicate zeolites are traditionally used in high-temperature applications at low water vapour pressures where the zeolite framework is generally considered to be stable and static. Increasingly, being for under milder aqueous conditions. However, it has not yet been established how neutral liquid mild conditions affects stability of framework. Here, we show that covalent bonds chabazite (CHA) labile when contact with water, which leads partial but fully reversible hydrolysis without...
While the structures of Brønsted acid sites (BAS) in zeolites are well understood, those Lewis (LAS) remain an active area investigation. Under hydrated conditions, reversible formation framework-associated octahedral aluminum has been observed acidic form. However, structure and mechanisms currently unknown. In this work, combined experimental 27 Al NMR spectroscopy computational data reveal for first time details zeolite aluminium. The LAS site becomes kinetically allowed thermodynamically...
A first-principles microkinetic model has been developed and applied to ethylene hydrogenation over close-packed transition-metal surfaces of Ru, Rh, Pd, Os, Ir, Pt. The is based on density functional theory calculations, which have used determine the activation energies elementary steps reaction according Horuiti–Polanyi mechanism. sensitivity analysis activity with respect kinetic parameters reveals distinctly different regimes across periodic table. For Ru controlled by energy for ethyl...
Löwenstein's rule is explained in terms of the level solvating water inside zeolite pores, along with formation Brønsted acidic clusters derived from framework sites.
Pt atoms and small clusters move through the zeolite framework via distinct mechanisms, leading to complex size-dependent diffusivity.
We present experimental and theoretical studies of the optical response mixed \documentclass[12pt]{minimal}\begin{document}${\rm Ag}_{n}{\rm Au}_{4-n}^{+}$\end{document} Ag n Au 4−n+ (n=1–3) clusters in photon energy range ℏω = 1.9–3.5 eV. Absorption spectra are recorded by a newly built longitudinal molecular beam depletion spectroscopy apparatus providing lower limits to absolute photodissociation cross sections. The data compared calculations framework long-range corrected time-dependent...
Density functional theory calculations are used to investigate the catalytic hydrogenation of ethylene ethane over a wide range transition metal (TM) surfaces. Assuming Horuiti–Polanyi mechanism, enthalpies adsorption, surface diffusion, and barriers examined close-packed surfaces Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, Au. Special attention is given effects hydrogen coverage on reaction pathway activation energies. The previously suggested importance balance between di-σ π adsorption modes...
The mechanism by which single metal atoms and small, zeolite-encapsulated particles are stabilized against migration growth is not currently well understood. In this work, we employ an unbiased density functional global optimization strategy to identify the locations energetic barriers for pathways between sites platinum (Pt) confined within microporous volume of a purely silicious zeolite with Linde type A topology its aluminosilicate borosilicate variants. We observe impressive...
AuAg nanoclusters are promising supported co-catalysts for photocatalytic hydrogen reduction. However, beyond the quantum regime (N > 100) little is known about how electronic properties of these nanoparticles affected by chemical ordering. We investigate effects ordering on 147-atom cuboctahedral nanoclusters, using empirical potentials coupled with an atomic-swap basin-hopping search to optimise elemental distribution, lowest energy arrangements then reminimised Density Functional Theory...
Global optimisation of catalytically relevant noble metal mono and bimetallic clusters is performed directly on an MgO substrate with DFT. Charge distributed locally upon the cluster, providing a means to atomically control binding reaction sites, as found for CO molecules Pd/Ag/Pt.
Supported metal nanoparticles are used as heterogeneous catalysts but often deactivated due to sintering at high temperatures. Confining species into a porous matrix reduces sintering, yet supports rarely provide additional stabilization. Here, we the silanol-rich layered zeolite IPC-1P stabilize ultra-small Rh nanoparticles. By adjusting interlayer space through swelling, prepared various architectures, including microporous and disordered mesoporous. In situ scanning transmission electron...
We analyze in detail how the interplay between electronic structure and cluster geometry determines stability fragmentation channels of single Pd-doped cationic Au clusters, $\mathrm{PdA}{\mathrm{u}}_{N}{}_{\ensuremath{-}1}{}^{+}$ ($N=2\ensuremath{-}20$). For this purpose, a combination photofragmentation experiments density functional theory calculations was employed. A remarkable agreement experiment is obtained. Pd doping found to modify particular altering two-dimensional...
Pd plays a crucial role in enhancing CO adsorption strength, through both direct and indirect means.
Acidic zeolites are one of the most important catalysts. In many their catalytic applications, mode interaction with water heavily influences activity, efficiency, and durability as a catalyst. Despite recent (first principles) computational efforts to understand mechanistic underpinning water-zeolite interactions, it is still prohibitively expensive carry out comprehensive studies employing realistic zeolitic models. Therefore, we used recently developed reactive neural network-based...
The effect of Pd doping on the structure and optical absorption small cationic gold clusters is investigated by a combined photodissociation spectroscopy time‐dependent density functional theory study Au n + Ar p PdAu ‐1 ( = 4,5; 0,1). While pure are planar, Pd‐doped 3D. UV–visible studied in 2.0–4.7 eV photon energy range, allowing observation previously unreported bands for 4 Ar. oscillator strength transitions dramatically reduced upon incorporating atom Ar, while this less pronounced 5...
Operando modelling of 27 Al NMR in zeolites, showing the importance hydration and dynamics reproducing experimental data. Machine learning analysis obtains a simple correlation chemical shielding which predicts shifts accurately.
Abstract The energy landscapes of sub‐nanometre bimetallic coinage metal clusters are explored with the Threshold Algorithm coupled Birmingham Cluster Genetic Algorithm. Global and energetically low‐lying minima along their permutational isomers located for Cu ${_4 }$ Ag cluster Gupta potential density functional theory (DFT). Statistical tools employed to map connectivity landscape growth structural basins, while thermodynamics interconversion probed, based on probability flows between...
The effect of cluster size, oxidation state, and the support upon structures energetics subnanometer palladium nanoparticles is investigated within a density functional framework. Gas phase global minima Pd4 Pd10 along with their suboxide counterparts are determined using genetic algorithm deposited MgO (001) high-index alumina surface. It observed that there an oxidation-dependent transition in smaller clusters from three-dimensional to two-dimensional both gas when supported by strongly...