A5027432625- Catalytic Processes in Materials Science
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Catalysts for Methane Reforming
- Catalysis and Oxidation Reactions
- Organometallic Complex Synthesis and Catalysis
- Asymmetric Hydrogenation and Catalysis
- Zeolite Catalysis and Synthesis
- Electrocatalysts for Energy Conversion
- Carbon dioxide utilization in catalysis
- Nanomaterials for catalytic reactions
- Catalysis and Hydrodesulfurization Studies
- Advanced NMR Techniques and Applications
- Catalysis for Biomass Conversion
- Ammonia Synthesis and Nitrogen Reduction
- MXene and MAX Phase Materials
- CO2 Reduction Techniques and Catalysts
- Mesoporous Materials and Catalysis
- Advanced Photocatalysis Techniques
- Chemical Synthesis and Characterization
- Catalytic C–H Functionalization Methods
- nanoparticles nucleation surface interactions
- Advanced Chemical Physics Studies
- Nanoporous metals and alloys
- Catalytic Cross-Coupling Reactions
Universitat Autònoma de Barcelona
2010-2025
TU Wien
2022-2025
Universitat de Barcelona
2023
Centre for Research on Ecology and Forestry Applications
2021
ETH Zurich
2012-2020
Institute of Inorganic Chemistry of the Slovak Academy of Sciences
2019
Charles Humbert 8
2014-2017
Board of the Swiss Federal Institutes of Technology
2014-2015
Universität Ulm
2011-2013
Centre National de la Recherche Scientifique
2007
Abstract Methanol synthesis by CO 2 hydrogenation is a key process in methanol‐based economy. This reaction catalyzed supported copper nanoparticles and displays strong support or promoter effects. Zirconia known to enhance both the methanol production rate selectivity. Nevertheless, origin of this observation mechanisms associated with conversion still remain unknown. A mechanistic study on Cu/ZrO presented. Using kinetics, situ IR NMR spectroscopies, isotopic labeling strategies, surface...
The dry reforming of methane (DRM), i.e., the reaction and CO2 to form a synthesis gas, converts two major greenhouse gases into useful chemical feedstock. In this work, we probe effect role Fe in bimetallic NiFe catalysts. To end, monometallic Ni, Fe, Ni-Fe catalysts supported on MgxAlyOz matrix derived via hydrotalcite-like precursor were synthesized. Importantly, textural features catalysts, specific surface area (172-178 m2/gcat), pore volume (0.51-0.66 cm3/gcat), particle size (5.4-5.8...
Transition metal nanoparticles (NPs) are typically supported on oxides to ensure their stability, which may result in modification of the original NP catalyst reactivity. In a number cases, this is related formation NP/support interface sites that play role catalysis. The metal/support effect verified experimentally commonly ascribed stronger reactants adsorption or facile activation such compared bare NPs, as indicated by DFT-derived potential energy surfaces (PESs). However, relevance...
Au(III)−Schiff base complexes are active hydrogenation catalysts, giving turnover frequencies similar to those of the corresponding Pd(II), which has same d8 electronic structure as Au(III). The mechanism reaction been studied in detail by a combination kinetic experiments and theoretical calculations. It is predicted tested that nature solvent plays critical role for heterolytic cleavage H2 (controlling step). Taking this into account, properly selecting solid supports (polarity...
Abstract Dynamic nuclear polarization surface enhanced NMR (DNP‐SENS), Mössbauer spectroscopy, and computational chemistry were combined to obtain structural information on the active‐site speciation in Sn‐β zeolite. This approach unambiguously shows presence of framework Sn IV ‐active sites an octahedral environment, which probably correspond so‐called open closed sites, respectively (namely, tin bound three or four siloxy groups zeolite framework).
In this contribution, realistic amorphous SiO2 models of 2.1 × nm with silanol densities ranging 1.1-7.2 OH per nm(2) are obtained by means ab initio calculations via the dehydroxylation a fully hydroxylated silica surface. The dehydroxyation process is considered to take place direct condensation adjacent groups and migration steps. latter reconstructions needed in order obtain highly dehydroxylated surfaces favorable energetics without formation defects. surface phase diagram different as...
Mononuclear Cr(III) surface sites were synthesized from grafting [Cr(OSi(O(t)Bu)3)3(tetrahydrofurano)2] on silica partially dehydroxylated at 700 °C, followed by a thermal treatment under vacuum, and characterized infrared, ultraviolet-visible, electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS). These are highly active in ethylene polymerization to yield polyethylene with broad molecular weight distribution, similar that typically obtained the Phillips catalyst. CO...
Sn-β zeolites prepared using different recipes feature very catalytic activities for aqueous phase glucose isomerization, suggesting the presence of active sites. A systematic study morphology and atomic-level structure materials DNP NMR spectroscopy in combination with first-principles calculations allows discrimination between potential sites leads to a proposal specific structural features that are important high activity. The results indicate showing highest activity possess highly...
We describe the reactivity of well-defined chromium silicates toward ethylene and propane. The initial motivation for this study was to obtain a molecular understanding Phillips polymerization catalyst. catalyst contains reduced sites on silica catalyzes without activators or preformed Cr-C bond. Cr(II) are commonly proposed active in synthesized characterized chromium(II) found that these materials, slightly contaminated with minor amount Cr(III) sites, have poor activity few sites. In...
The methanol-to-olefin (MTO) process allows the conversion of methanol/dimethyl ether into olefins on acidic zeolites via so-called hydrocarbon pool mechanism. However, site and mechanism formation first carbon-carbon bond are still a matter debate. Here, we show that Lewis Al sites 110 facet γ-Al2O3 can readily activate dimethyl to yield CH4, alkenes, surface formate species according spectroscopic studies combined with computational approach. forming step as well methane involves transient...
Due to the impact of anthropogenic CO2 emissions on global warming, conversion this molecule useful products is increasing interest. Therefore, further understanding activation needed. Ni-based catalysts are able dissociate and convert into fuels, although these systems generally simulated using simple slab models, real significantly more complex. They composed nanoparticles supported oxides, being γ-Al2O3 one most widely used supports. In study, we perform ab initio simulations in order...
Abstract The two-dimensional morphology of molybdenum oxycarbide (2D-Mo 2 CO x ) nanosheets dispersed on silica is found vital for imparting high stability and catalytic activity in the dry reforming methane. Here we report that owing to maximized metal utilization, specific 2D-Mo /SiO exceeds other Mo C catalysts by ca. 3 orders magnitude. activated , yielding a surface oxygen coverage optimal its performance oxidation state +4. According ab initio calculations, DRM proceeds sites nanosheet...
A biphasic reaction approach is presented for the cycloaddition of CO 2 to epoxides where catalyst dissolved in water droplets and occurs at aqueous–organic interface allowing easy recycling by decantation.
Transformations of oxygenates (CO2, CO, H2O, etc.) via Mo2C-based catalysts are facilitated by the high oxophilicity material; however, this can lead to formation oxycarbides and complicate identification (most) active catalyst state sites. In context, two-dimensional (2D) MXene molybdenum carbide Mo2CTx (Tx passivating surface groups) contains only Mo sites is therefore a highly suitable model for structure–activity studies. Here, we report that catalytic activity in Fischer–Tropsch (FT)...
The Shvo catalyst is one of the most prominent examples a hydrogen-transfer successfully applied in broad scope processes. reaction takes place by transferring hydride (bonded to metal center) and proton ligand) double bond. mechanism for process, however, matter controversy. Experimental studies means primary deuterium isotope effects on hydrogenation ketones via active reducing form Casey Bäckvall groups concluded that carbonyl concerted. Nevertheless, it not clear whether goes through an...
Abstract DFT calculations have been used to analyze the degree of metal‐to‐ligand backbonding in a range model transition metal complexes N‐heterocyclic carbenes. Two new methods analysis introduced for this purpose. The first is structural and involves comparing variation C–N bond length N–C–N angle which σ‐donation dominant (e.g. with BF 3 ) others might be expected. second uses perturbative natural bonding orbital (NBO) method. Both lead firm conclusion that significant these compounds –...
Carbon monoxide is a ubiquitous molecule, key feedstock and intermediate in chemical processes. Its adsorption activation, typically carried out on metallic nanoparticles (NPs), are strongly dependent the particle size. In particular, small NPs, which principle contain more corner step-edge atoms, surprisingly less reactive than larger ones. Hereby, first-principles calculations explicit Ru NP models (1-2 nm) show that both large NPs can present sites (e.g., B5 B6 sites). However, such...
Heterogeneous catalysts in the form of atomically dispersed metals on a support provide most efficient utilization active component, which is especially important for scarce and expensive late transition metals. These also enable unique opportunities to understand reaction pathways through detailed spectroscopic computational studies. Here, we demonstrate that iridium sites indium tin oxide prepared via surface organometallic chemistry display exemplary catalytic activity one challenging...
Grafting molecular precursors on partially dehydroxylated silica followed by a thermal treatment yields silica-supported M(III) sites for broad range of metals. They display unique properties such as high activity in olefin polymerization and alkane dehydrogenation (M = Cr) or efficient luminescence Yb Eu) essential bioimaging. Here, we interrogate the local structure surface obtained from two precursors, amides M(N(SiMe3)2)3 vs siloxides (M(OSi(OtBu)3)3·L with L (THF)2 HOSi(OtBu)3 M Cr, Yb,...
Lead-halide perovskites increasingly mesmerize researchers because they exhibit a high degree of structural defects and dynamics yet nonetheless offer an outstanding (opto)electronic performance on par with the best examples structurally stable defect-free semiconductors. This highly unusual feature necessitates adoption experimental theoretical mindset reexamination techniques that may be uniquely suited to understand these materials. Surprisingly, suite methods for characterization...
Nonoxidative dehydrogenation of light alkanes has seen a renewed interest in recent years. While PtGa systems appear among the most efficient catalyst for this reaction and are now implemented production plants, origin high catalytic performance terms activity, selectivity, stability PtGa-based catalysts is largely unknown. Here we use molecular modeling at DFT level on three different models: (i) periodic surfaces, (ii) clusters using static calculations, (iii) realistic size...