108.
Berti, Andrea; Bergua, Ramón M.; Mercero, Jose M.; Perco, Deborah; Lacovig, Paolo; Lizzit, Silvano; Jimenez-Izal, Elisa; Baraldi, Alessandro
Ultra-Low Atomic Diffusion Barrier on Two-Dimensional Materials: The Case of Pt on Epitaxial Graphene Journal Article
ACS Nano, 2025, 19(40), 35921--35932
@article{Berti2025,
title = {Ultra-Low Atomic Diffusion Barrier on Two-Dimensional Materials: The Case of Pt on Epitaxial Graphene},
author = {Andrea Berti and Ramón M. Bergua and Jose M. Mercero and Deborah Perco and Paolo Lacovig and Silvano Lizzit and Elisa Jimenez-Izal and Alessandro Baraldi},
doi = {10.1021/acsnano.5c13305},
issn = {1936-086X},
year = {2025},
date = {2025-10-14},
urldate = {2025-10-14},
journal = {ACS Nano},
volume = {19},
number = {40},
pages = {35921--35932},
publisher = {American Chemical Society (ACS)},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
107.
Boutou, Élodie; Lew-Yee, Juan Felipe Huan; Mercero, Jose M.; Piris, Mario
Enhancing the computational efficiency of the DoNOF program through a new orbital sorting scheme Journal Article
Advances in Quantum Chemistry, 2025, 91, 169--189
@article{2025,
title = {Enhancing the computational efficiency of the DoNOF program through a new orbital sorting scheme},
author = {Élodie Boutou and Juan Felipe Huan Lew-Yee and Jose M. Mercero and Mario Piris},
doi = {10.1016/bs.aiq.2025.03.001},
isbn = {9780443343575},
year = {2025},
date = {2025-02-04},
urldate = {2025-02-04},
booktitle = {Advances in Quantum Chemistry},
journal = {Advances in Quantum Chemistry},
volume = {91},
pages = {169--189},
publisher = {Elsevier},
abstract = {This work presents a novel approach to distribute orbitals into subspaces within electron-pairing-based natural orbital functionals (NOFs). This approach modifies the coupling between weakly and strongly occupied orbitals by applying an alternating orbital sorting strategy. In contrast to the previous orbital sorting that enforced electron pairing within subspaces of contiguous orbitals, the new approach provides greater flexibility, enabling a calculation scheme where the size of the subspaces can be gradually expanded. As a consequence, one can start using subspaces of only one weakly occupied orbital (perfect pairing) and progressively enlarge their size by incorporating more weakly occupied orbitals (extended pairing) up to the maximum size allowed by the basis set. In this way, the alternate orbital sorting allows solving first a simpler problem with small subspaces and leverage its orbital solution for the more intensive problem with larger subspaces, thereby reducing the overall computational cost and improving convergence, as we observed in the DoNOF program. The efficiency provided by the new sorting approach has been validated through benchmark calculations in H2O, H2O2, and NH3. In particular, we compared three strategies: (i) solving directly the calculation with the largest subspaces (one-shot strategy), as was usually done before this work, (ii) starting with perfect pairing and stepwise increasing the number of orbitals in the subspaces one by one until reaching the maximum size (incremental strategy), and (iii) starting with perfect pairing and transitioning directly to the maximum subspace size (two-step strategy). Our results show that the two-step approach emerges as the most effective strategy, achieving the lowest computational cost while maintaining high accuracy. These results confirm that the alternating orbital sorting scheme provides a robust and scalable framework for improving NOF calculations and could be particularly advantageous for extending these methods to larger and strongly correlated systems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This work presents a novel approach to distribute orbitals into subspaces within electron-pairing-based natural orbital functionals (NOFs). This approach modifies the coupling between weakly and strongly occupied orbitals by applying an alternating orbital sorting strategy. In contrast to the previous orbital sorting that enforced electron pairing within subspaces of contiguous orbitals, the new approach provides greater flexibility, enabling a calculation scheme where the size of the subspaces can be gradually expanded. As a consequence, one can start using subspaces of only one weakly occupied orbital (perfect pairing) and progressively enlarge their size by incorporating more weakly occupied orbitals (extended pairing) up to the maximum size allowed by the basis set. In this way, the alternate orbital sorting allows solving first a simpler problem with small subspaces and leverage its orbital solution for the more intensive problem with larger subspaces, thereby reducing the overall computational cost and improving convergence, as we observed in the DoNOF program. The efficiency provided by the new sorting approach has been validated through benchmark calculations in H2O, H2O2, and NH3. In particular, we compared three strategies: (i) solving directly the calculation with the largest subspaces (one-shot strategy), as was usually done before this work, (ii) starting with perfect pairing and stepwise increasing the number of orbitals in the subspaces one by one until reaching the maximum size (incremental strategy), and (iii) starting with perfect pairing and transitioning directly to the maximum subspace size (two-step strategy). Our results show that the two-step approach emerges as the most effective strategy, achieving the lowest computational cost while maintaining high accuracy. These results confirm that the alternating orbital sorting scheme provides a robust and scalable framework for improving NOF calculations and could be particularly advantageous for extending these methods to larger and strongly correlated systems.
106.
Grande‐Aztazi, Rafael; Matito, Eduard; Ugalde, Jesus M.; Mercero, Jose M.
The Aromaticity of Osmapentalenes Derivatives – An Analysis Based on Electron‐Delocalization Indices Journal Article
ChemPhysChem, 2025, 26(3)
@article{Grande‐Aztazi2024,
title = {The Aromaticity of Osmapentalenes Derivatives – An Analysis Based on Electron‐Delocalization Indices},
author = {Rafael Grande‐Aztazi and Eduard Matito and Jesus M. Ugalde and Jose M. Mercero},
doi = {10.1002/cphc.202400713},
issn = {1439-7641},
year = {2025},
date = {2025-02-01},
journal = {ChemPhysChem},
volume = {26},
number = {3},
publisher = {Wiley},
abstract = {<jats:title>Abstract</jats:title><jats:p>A systematic investigation of the aromatic features of the electronic structures of a family of recently synthesized osmapentalene derivatives has been carried by means of indices derived from the calculated one‐electron density matrix of the corresponding geometry optimized compounds, and complemented by the analysis of the valence molecular orbitals and the delocalized bonding units emerging from the adaptive natural density partitioning method. The calculated delocalization indices between consecutive atom pairs, and normalized multicenter indices are very suggestive of the aromatic character of the equatorial fused carbon rings (except triangular ones) for all the members of the family. Since the electron‐delocalization based indices allow precise quantification of the aromaticity, differences of the aromatic character among the various members have also been highlighted, and have been found to be consistent with the magnetic based criteria indices reported earlier. Finally, the valence molecular orbitals along with the delocalized bonding units of the adaptive natural density partitioning indicate that the aromaticity of these compounds is sustained by either 10 or 14 <jats:italic>π</jats:italic> electrons, which satisfy the Hückel aromatic electron counting rule.</jats:p>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:title>Abstract</jats:title><jats:p>A systematic investigation of the aromatic features of the electronic structures of a family of recently synthesized osmapentalene derivatives has been carried by means of indices derived from the calculated one‐electron density matrix of the corresponding geometry optimized compounds, and complemented by the analysis of the valence molecular orbitals and the delocalized bonding units emerging from the adaptive natural density partitioning method. The calculated delocalization indices between consecutive atom pairs, and normalized multicenter indices are very suggestive of the aromatic character of the equatorial fused carbon rings (except triangular ones) for all the members of the family. Since the electron‐delocalization based indices allow precise quantification of the aromaticity, differences of the aromatic character among the various members have also been highlighted, and have been found to be consistent with the magnetic based criteria indices reported earlier. Finally, the valence molecular orbitals along with the delocalized bonding units of the adaptive natural density partitioning indicate that the aromaticity of these compounds is sustained by either 10 or 14 <jats:italic>π</jats:italic> electrons, which satisfy the Hückel aromatic electron counting rule.</jats:p>
105.
Ugartemendia, Andoni; Bergua, Ramón M.; Mercero, Jose M.; Jimenez-Izal, Elisa
Boosting synergistic effects between PtGe nanoalloys and 2D materials for PEMFC applications Journal Article
International Journal of Hydrogen Energy, 2024, 89, 233--253
@article{Ugartemendia2024c,
title = {Boosting synergistic effects between PtGe nanoalloys and 2D materials for PEMFC applications},
author = {Andoni Ugartemendia and Ramón M. Bergua and Jose M. Mercero and Elisa Jimenez-Izal},
doi = {10.1016/j.ijhydene.2024.09.279},
issn = {0360-3199},
year = {2024},
date = {2024-11-01},
urldate = {2024-11-01},
journal = {International Journal of Hydrogen Energy},
volume = {89},
pages = {233--253},
publisher = {Elsevier BV},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
104.
Ugartemendia, Andoni; Mercero, José M.; Jimenez‐Izal, Elisa; de Cózar, Abel
Doping Efects on Ethane/Ethylene Dehydrogenation Catalyzed by Pt2X Nanoclusters Journal Article
ChemPhysChem, 2024, 25(12)
@article{Ugartemendia2024d,
title = {Doping Efects on Ethane/Ethylene Dehydrogenation Catalyzed by Pt_{2}X Nanoclusters},
author = {Andoni Ugartemendia and José M. Mercero and Elisa Jimenez‐Izal and Abel de Cózar},
doi = {10.1002/cphc.202400095},
issn = {1439-7641},
year = {2024},
date = {2024-06-17},
urldate = {2024-06-17},
journal = {ChemPhysChem},
volume = {25},
number = {12},
publisher = {Wiley},
abstract = {<jats:title>Abstract</jats:title><jats:p>The catalytic dehydrogenation of light alkanes is key to transform low‐cost hydrocarbons to high value‐added chemicals. Although Pt is extremely efficient at catalyzing this reaction, it suffers from coke formation that deactivates the catalyst. Dopants such as Sn are widely used to increase the stability and lifetime of Pt. In this work, the dehydrogenation reaction of ethane catalyzed by Pt<jats:sub>3</jats:sub> and Pt<jats:sub>2</jats:sub>X (X=Si, Ge, Sn, P and Al) nanocatalysts has been studied computationally by means of density functional calculations. Our results show how the presence of dopants in the nanocluster structure affects its electronic properties and catalytic activity. Exploration of the potential energy surfaces show that non–doped catalyst Pt<jats:sub>3</jats:sub> present low selectivity towards ethylene formation, where acetylene resulting from double dehydrogenation reaction will be obtained as a side product (in agreement with the experimental evidence). On the contrary, the inclusion of Si, Ge, Sn, P or Al as dopant agents implies a selectivity enhancement, where acetylene formation is not energetically favoured. These results demonstrate the effectiveness of such dopant elements for the design of Pt–based catalysts on ethane dehydrogenation.</jats:p>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:title>Abstract</jats:title><jats:p>The catalytic dehydrogenation of light alkanes is key to transform low‐cost hydrocarbons to high value‐added chemicals. Although Pt is extremely efficient at catalyzing this reaction, it suffers from coke formation that deactivates the catalyst. Dopants such as Sn are widely used to increase the stability and lifetime of Pt. In this work, the dehydrogenation reaction of ethane catalyzed by Pt<jats:sub>3</jats:sub> and Pt<jats:sub>2</jats:sub>X (X=Si, Ge, Sn, P and Al) nanocatalysts has been studied computationally by means of density functional calculations. Our results show how the presence of dopants in the nanocluster structure affects its electronic properties and catalytic activity. Exploration of the potential energy surfaces show that non–doped catalyst Pt<jats:sub>3</jats:sub> present low selectivity towards ethylene formation, where acetylene resulting from double dehydrogenation reaction will be obtained as a side product (in agreement with the experimental evidence). On the contrary, the inclusion of Si, Ge, Sn, P or Al as dopant agents implies a selectivity enhancement, where acetylene formation is not energetically favoured. These results demonstrate the effectiveness of such dopant elements for the design of Pt–based catalysts on ethane dehydrogenation.</jats:p>
103.
Escayola, Sílvia; Jimenez-Izal, Elisa; Matito, Eduard; Ugalde, Jesus M.; Grande-Aztatzi, Rafael; Mercero, Jose M.
Unveiling the quantum secrets of triel metal triangles: a tale of stability, aromaticity, and relativistic effects Journal Article
Phys. Chem. Chem. Phys., 2024, 26(16), 12619--12627
@article{Escayola2024,
title = {Unveiling the quantum secrets of triel metal triangles: a tale of stability, aromaticity, and relativistic effects},
author = {Sílvia Escayola and Elisa Jimenez-Izal and Eduard Matito and Jesus M. Ugalde and Rafael Grande-Aztatzi and Jose M. Mercero},
doi = {10.1039/d4cp00484a},
issn = {1463-9084},
year = {2024},
date = {2024-04-24},
journal = {Phys. Chem. Chem. Phys.},
volume = {26},
number = {16},
pages = {12619--12627},
publisher = {Royal Society of Chemistry (RSC)},
abstract = {MCSCF natural orbitals and the corresponding number of (α/β) electrons and its aromaticity (Hückel), Baird odd-symmetry anti-aromaticity and Baird odd-symmetry aromaticity after applying Mandados rules. },
keywords = {},
pubstate = {published},
tppubtype = {article}
}
102.
Ugartemendia, Andoni; Casademont-Reig, Irene; Zhao, Lili; Zhang, Zuxian; Frenking, Gernot; Ugalde, Jesus M.; Garcia-Lekue, Aran; Jimenez-Izal, Elisa
Deciphering the chemical bonding of the trivalent oxygen atom in oxygen doped graphene Journal Article
Chem. Sci., 2024, 15(16), 6151--6159
@article{Ugartemendia2024b,
title = {Deciphering the chemical bonding of the trivalent oxygen atom in oxygen doped graphene},
author = {Andoni Ugartemendia and Irene Casademont-Reig and Lili Zhao and Zuxian Zhang and Gernot Frenking and Jesus M. Ugalde and Aran Garcia-Lekue and Elisa Jimenez-Izal},
doi = {10.1039/d4sc00142g},
issn = {2041-6539},
year = {2024},
date = {2024-04-24},
urldate = {2024-04-24},
journal = {Chem. Sci.},
volume = {15},
number = {16},
pages = {6151--6159},
publisher = {Royal Society of Chemistry (RSC)},
abstract = {<jats:p>The recently observed tricoordinated oxygen embedded in graphene is theoretically explored. Using a variety of state-of-the-art methods the factors influencing the stabilization of trivalent oxygen are deciphered.</jats:p>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:p>The recently observed tricoordinated oxygen embedded in graphene is theoretically explored. Using a variety of state-of-the-art methods the factors influencing the stabilization of trivalent oxygen are deciphered.</jats:p>
101.
Bergua, Ramon M.; Pavloudis, Theodoros; Ugartemendia, Andoni; Palmer, Richard E.; Jimenez-Izal, Elisa
PdTi alloys as an excellent catalyst for semi-hydrogenation reactions Journal Article
Applied Surface Science, 2024, 672
@article{Bergua2024,
title = {PdTi alloys as an excellent catalyst for semi-hydrogenation reactions},
author = {Ramon M. Bergua and Theodoros Pavloudis and Andoni Ugartemendia and Richard E. Palmer and Elisa Jimenez-Izal},
doi = {10.1016/j.apsusc.2024.160798},
issn = {0169-4332},
year = {2024},
date = {2024-03-05},
journal = {Applied Surface Science},
volume = {672},
publisher = {Elsevier BV},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
100.
Gastearena, Xuban; Ugalde, Jesus M.; Pieslinger, German E.; Sebastian, Eider San; Jimenez-Izal, Elisa
Unveiling the electronic origin of lanthanide based Metal Organic Framework with ideal spin filtering capacity Journal Article
Commun Phys, 2024, 7(1)
@article{Gastearena2024,
title = {Unveiling the electronic origin of lanthanide based Metal Organic Framework with ideal spin filtering capacity},
author = {Xuban Gastearena and Jesus M. Ugalde and German E. Pieslinger and Eider San Sebastian and Elisa Jimenez-Izal},
doi = {10.1038/s42005-024-01651-4},
issn = {2399-3650},
year = {2024},
date = {2024-02-13},
urldate = {2024-02-13},
journal = {Commun Phys},
volume = {7},
number = {1},
publisher = {Springer Science and Business Media LLC},
abstract = {<jats:title>Abstract</jats:title><jats:p>Recently, a three dimensional metal-organic framework (MOF) based on Dy(III) and the L-tartrate ligand was experimentally shown to exhibit a spin polarization (SP) power of 100% at room temperature. The material’s spin filtering ability was ascribed to the chiral-induced spin selectivity (CISS) effect. In this work, we computationally characterize the electronic structure of this MOF, revealing that the high SP of the material is linked to the asymmetric arrangement, around the Fermi level, of the alpha- and beta-spin electron states arising from the 4f-states of the lanthanide Dy atom, which results in two different conduction channels (band gaps) for each spin state. Based on the understanding gathered in this work, we propose that the substitution of the hydroxyl groups of the ligand by mercaptan groups should boost the electrical conductivity, while retaining the spin filtering power of the material.</jats:p>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:title>Abstract</jats:title><jats:p>Recently, a three dimensional metal-organic framework (MOF) based on Dy(III) and the L-tartrate ligand was experimentally shown to exhibit a spin polarization (SP) power of 100% at room temperature. The material’s spin filtering ability was ascribed to the chiral-induced spin selectivity (CISS) effect. In this work, we computationally characterize the electronic structure of this MOF, revealing that the high SP of the material is linked to the asymmetric arrangement, around the Fermi level, of the alpha- and beta-spin electron states arising from the 4f-states of the lanthanide Dy atom, which results in two different conduction channels (band gaps) for each spin state. Based on the understanding gathered in this work, we propose that the substitution of the hydroxyl groups of the ligand by mercaptan groups should boost the electrical conductivity, while retaining the spin filtering power of the material.</jats:p>
99.
Ugartemendia, Andoni; Mercero, Jose M.; de Cózar, Abel; Melander, Marko M.; Akola, Jaakko; Jimenez‐Izal, Elisa
Deposited PtGe Clusters as Active and Durable Catalysts for CO Oxidation** Journal Article
ChemCatChem, 2024, 16(3)
@article{Ugartemendia2024,
title = {Deposited PtGe Clusters as Active and Durable Catalysts for CO Oxidation**},
author = {Andoni Ugartemendia and Jose M. Mercero and Abel de Cózar and Marko M. Melander and Jaakko Akola and Elisa Jimenez‐Izal},
doi = {10.1002/cctc.202301137},
issn = {1867-3899},
year = {2024},
date = {2024-02-08},
urldate = {2024-02-08},
journal = {ChemCatChem},
volume = {16},
number = {3},
publisher = {Wiley},
abstract = {<jats:title>Abstract</jats:title><jats:p>Control of CO emissions raises serious environmental concerns in the current chemical industry, as well as in nascent technologies based on hydrogen such as electrolyzers and fuel cells. As for now, Pt remains one of the state‐of‐the‐art catalysts for the CO oxidation reaction, but unfortunately, it suffers from CO self‐poisoning. Recently, Pt−Ge alloys were proposed to be an excellent alternative to reduce CO poisoning. This work investigates the impact of Ge content on the CO oxidation kinetics of Pt<jats:sub>4</jats:sub>Ge<jats:sub>n</jats:sub> subnanoclusters supported on MgO. A Ge concentration dependence of the reaction kinetics is found due to a strong synergy between Pt and Ge. Pt−Ge nanoalloys act as a bifunctional catalyst by displaying dual adsorption sites; i. e., CO is adsorbed on Pt whereas oxygen binds to Ge, forming an alternative oxygen source GeO<jats:sub>x</jats:sub>. Besides, Ge alloying modifies the electronic structure of Pt (ligand effects) and reduces the affinity to CO. In this way, the competition between CO and O<jats:sub>2</jats:sub> adsorption and the overbinding of CO is alleviated, achieving a CO poisoning‐free kinetic regime. Our calculations suggest that Pt<jats:sub>4</jats:sub>Ge<jats:sub>3</jats:sub> is the optimal catalyst, evidencing that alloying composition is a parameter of extreme importance in nanocatalyst design. The work relies on global optimization search techniques to determine the accessibility of multiple structures at different conditions, mechanistic studies and microkinetic modeling.</jats:p>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:title>Abstract</jats:title><jats:p>Control of CO emissions raises serious environmental concerns in the current chemical industry, as well as in nascent technologies based on hydrogen such as electrolyzers and fuel cells. As for now, Pt remains one of the state‐of‐the‐art catalysts for the CO oxidation reaction, but unfortunately, it suffers from CO self‐poisoning. Recently, Pt−Ge alloys were proposed to be an excellent alternative to reduce CO poisoning. This work investigates the impact of Ge content on the CO oxidation kinetics of Pt<jats:sub>4</jats:sub>Ge<jats:sub>n</jats:sub> subnanoclusters supported on MgO. A Ge concentration dependence of the reaction kinetics is found due to a strong synergy between Pt and Ge. Pt−Ge nanoalloys act as a bifunctional catalyst by displaying dual adsorption sites; i. e., CO is adsorbed on Pt whereas oxygen binds to Ge, forming an alternative oxygen source GeO<jats:sub>x</jats:sub>. Besides, Ge alloying modifies the electronic structure of Pt (ligand effects) and reduces the affinity to CO. In this way, the competition between CO and O<jats:sub>2</jats:sub> adsorption and the overbinding of CO is alleviated, achieving a CO poisoning‐free kinetic regime. Our calculations suggest that Pt<jats:sub>4</jats:sub>Ge<jats:sub>3</jats:sub> is the optimal catalyst, evidencing that alloying composition is a parameter of extreme importance in nanocatalyst design. The work relies on global optimization search techniques to determine the accessibility of multiple structures at different conditions, mechanistic studies and microkinetic modeling.</jats:p>