Search

Your search keyword '"Duca, Dario"' showing total 311 results
Start Over Author "Duca, Dario"
311 results on '"Duca, Dario"'

8. Decomposition of guaiacol on a subnanometric platinum cluster: a DFT investigation followed by microkinetic analysis.

Author

Nania, Chiara, Ferrante, Francesco, Bertini, Marco, Gueci, Laura, and Duca, Dario

Abstract

The use of biomass as renewable feedstock for commodity chemicals may largely benefit from the successful development and application of heterogeneous catalysts for decomposition processes. The present investigation combines density functional theory and Christiansen-like microkinetic analysis to describe, at the atomistic level, the mechanisms related to the conversion of oxygenated biomass compounds to deoxygenated and semi-saturated hydrocarbons on a subnanometric Pt10 cluster. The DFT calculations and the kinetic analysis based on the evaluated free energy variations, associated with both elementary step barriers and rearrangement/desorption processes occurring on the cluster, suggest that benzene is the preferred product, together with a compound still bearing oxygen, cyclopentadienone, which would form as a minor product only at high temperature. Other than highlighting the role of the peculiar interaction between carbon and platinum, the reported investigation underlines the importance of cluster fluxionality and reorganization ability in promoting catalyzed reactions. [ABSTRACT FROM AUTHOR]

Published
2025
Full Text
View/download PDF

15. Modified Halloysite as Catalyst for the Conversion of Hydroxymethylfurfural to Furandicarboxylic Acid: A DFT Investigation.

Author

Bertini, Marco, Ferrante, Francesco, Guercio, Ludovico, Lisuzzo, Lorenzo, and Duca, Dario

Subjects
DENSITY functional theory, AMINO group, HALLOYSITE, ACTIVATION energy, HYDROXYMETHYLFURFURAL
Abstract

The reaction steps involved in the 5‐hydroxymethylfurfural to 2,5‐furandicarboxylic acid conversion by means of H2O2 were investigated employing a dedicated computational protocol based on density functional theory. The catalytic environment of choice was a molecular model representing a portion of the halloysite nanotube outer surface, functionalized by an organosilane, the 3‐aminopropyltriethoxysilane, whose amino group bonds one gold atom. At this stage of the investigation, the process was fully detailed in terms of the interactions between the reaction intermediates and the catalyst, and the reaction standard free energies. In addition, the energy barriers of the elementary steps involving the hydrogen migration from the adsorbed organic species to the gold atom were analyzed. On the basis of the interaction geometries, a certain distinction among the preferred reaction path can be inferred as a function of the net negative charge characterizing the catalyst outer surface. Since the inner surface of halloysite can represent the acid environment needed to obtain 5‐hydroxymethylfurfural through dehydration of fructose, the present study is framed in a wider research field where the possibility to consider functionalized halloysite as one‐pot reactor for the valorization of biomass is explored. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

22. Ultrafast Interface Charge Separation in Carbon Nanodot-Nanotube Hybrids

Author

L'Oréal, Ministero dell'Istruzione, dell'Università e della Ricerca, Karlsruhe Institute of Technology, Ministerio de Ciencia, Innovación y Universidades (España), Sciortino, Alice [0000-0001-8361-3002], Ferrante, Francesco [0000-0002-2989-4365], Mauro, Nicolò [0000-0003-0246-3474], Buscarino, Gianpiero [0000-0001-8324-6783], Agnello, Simonpietro [0000-0002-0346-8333], Duca, Dario [0000-0003-0281-8634], Messina, Fabrizio [0000-0002-2130-0120], Sciortino, Alice, Ferrante, Francesco, Gonçalves, Gil, Tobias, Gerard, Popescu, Radian, Gerthsen, Dagmar, Mauro, Nicolò, Giammona, Gaetano, Buscarino, Gianpiero, Gelardi, Franco M, Agnello, Simonpietro, Cannas, Marco, Duca, Dario, Messina, Fabrizio, L'Oréal, Ministero dell'Istruzione, dell'Università e della Ricerca, Karlsruhe Institute of Technology, Ministerio de Ciencia, Innovación y Universidades (España), Sciortino, Alice [0000-0001-8361-3002], Ferrante, Francesco [0000-0002-2989-4365], Mauro, Nicolò [0000-0003-0246-3474], Buscarino, Gianpiero [0000-0001-8324-6783], Agnello, Simonpietro [0000-0002-0346-8333], Duca, Dario [0000-0003-0281-8634], Messina, Fabrizio [0000-0002-2130-0120], Sciortino, Alice, Ferrante, Francesco, Gonçalves, Gil, Tobias, Gerard, Popescu, Radian, Gerthsen, Dagmar, Mauro, Nicolò, Giammona, Gaetano, Buscarino, Gianpiero, Gelardi, Franco M, Agnello, Simonpietro, Cannas, Marco, Duca, Dario, and Messina, Fabrizio

Abstract

Carbon dots are an emerging family of zero-dimensional nanocarbons behaving as tunable light harvesters and photoactivated charge donors. Coupling them to carbon nanotubes, which are well-known electron acceptors with excellent charge transport capabilities, is very promising for several applications. Here, we first devised a route to achieve the stable electrostatic binding of carbon dots to multi- or single-walled carbon nanotubes, as confirmed by several experimental observations. The photoluminescence of carbon dots is strongly quenched when they contact either semiconductive or conductive nanotubes, indicating a strong electronic coupling to both. Theoretical simulations predict a favorable energy level alignment within these complexes, suggesting a photoinduced electron transfer from dots to nanotubes, which is a process of high functional interest. Femtosecond transient absorption confirms indeed an ultrafast (<100 fs) electron transfer independent of nanotubes being conductive or semiconductive in nature, followed by a much slower back electron transfer (≈60 ps) from the nanotube to the carbon dots. The high degree of charge separation and delocalization achieved in these nanohybrids entails significant photocatalytic properties, as we demonstrate by the reduction of silver ions in solution. The results are very promising in view of using these "all-carbon" nanohybrids as efficient light harvesters for applications in artificial photocatalysis and photosynthesis.

Published
2021

27. Ultrafast Interface Charge Separation in Carbon Nanodot–Nanotube Hybrids

Author

Sciortino, Alice, primary, Ferrante, Francesco, additional, Gonçalves, Gil, additional, Tobias, Gerard, additional, Popescu, Radian, additional, Gerthsen, Dagmar, additional, Mauro, Nicolò, additional, Giammona, Gaetano, additional, Buscarino, Gianpiero, additional, Gelardi, Franco M., additional, Agnello, Simonpietro, additional, Cannas, Marco, additional, Duca, Dario, additional, and Messina, Fabrizio, additional

Published
2021
Full Text
View/download PDF

45. Cation environment of BaCe[O.sub.3]-based protonic conductors: a computational study

Author

Cammarata, Antonio, Martorana, Antonino, and Duca, Dario

Subjects
Density functionals -- Usage, Semiconductor doping -- Analysis, Barium compounds -- Chemical properties, Cerium -- Chemical properties, Cerium -- Electric properties, Indium -- Chemical properties, Indium -- Electric properties, Chemicals, plastics and rubber industries
Published
2009

50. H−ZSM-5 Modified Zeolite: Quantum Chemical Models of Acidic Sites

Author

BARONE, Giampaolo, CASELLA, Girolamo, GIUFFRIDA, Sergio, DUCA, Dario, CASELLA, Antonio, BARONE G, CASELLA G, GIUFFRIDA S, DUCA D, and Casella, A.

Subjects
ONIOM, Silicon, Chemistry, Adsorption, Computational methods, Molecular modeling, Molecular structure, Quantum chemistry, Substitution reactions, chemistry.chemical_element, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, Adsorption, Aluminium, Computational chemistry, Atom, Tetrahedron, Physical chemistry, Physical and Theoretical Chemistry, ZSM-5, Zeolite
Abstract

A ZSM-5 fragment, containing 52 tetrahedral moieties, each of them formed by one silicon or one aluminum atom surrounded by four oxygen atoms, was employed to model (52T systems) by quantum chemical calculations (i) the influence of the positions of the acidic sites on the energetics of 22 aluminum monosubstituted and bisubstituted 52T acidic zeolite (H-ZSM-5) systems and (ii) the local adsorption properties and acidic strength of the corresponding -OH sites. The energetics and the structural properties of simpler acid H-ZSM-5 systems containing only five Tetrahedral moieties (5T systems) were also modeled for comparison. B3LYP/6-31G(d,p) partial geometry optimization routines were performed on the 5T and 52T systems. On the latter, ONIOM(B3LYP/6-31G(d,p)jAM1) calculations and an alternative approach, i.e., the ONIOM method followed by a single-point at the above B3LYP/6-31G(d,p) level, aimed to decrease the need of computational resources, were also employed to analyze the properties of the different H-ZSM-5 models. The whole results showed that the orientation and the position of the acidic hydrogen atoms within the zeolite channel strongly affect the stability of the model systems, irrespective of the starting local topology characterizing the Al T Si substitution site. Bro¨nsted gas-phase acidity strength and adsorption-ability were evaluated through the analysis of the energy involved in (i) the proton dissociation from the acidic sites and (ii) the cis-but-2-ene and trans-but-2-ene adsorption on the same acidic sites. Both were affected, although to a very different extent, by the location and number of the considered -OH acidic groups. In particular, 2 among the 12 modeled acidic sites resulted in a highly stabilized zeolite structure, pointing out that the Al T Si substitutions in the synthesis of aluminated ZSM-5 zeolites, and hence the corresponding catalytic activity, could preferentially occur on special sites. The choice of the computational method along with the size and the cutoff of the mimicked structures influenced the reliability of the calculations. The suggested alternative approach (that is, the ONIOM followed by the DFT single-point calculation) provided reasonable findings at very low computational cost.

Published
2007
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results