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316 results on '"Solla-Gullón, José"'

4. Three-dimensional coherent Bragg imaging of rotating nanoparticles

Author

Björling, Alexander, Marçal, Lucas A. B., Solla-Gullón, José, Wallentin, Jesper, Carbone, Dina, and Maia, Filipe R. N. C.

Subjects
Condensed Matter - Materials Science, Electrical Engineering and Systems Science - Image and Video Processing
Abstract

Bragg Coherent Diffraction Imaging (BCDI) is a powerful strain imaging tool, often limited by beam-induced sample instability for small particles and high power densities. Here, we devise and validate an adapted diffraction volume assembly algorithm, capable of recovering three-dimensional datasets from particles undergoing uncontrolled and unknown rotations. We apply the method to gold nanoparticles which rotate under the influence of a focused coherent X-ray beam, retrieving their three-dimensional shapes and strain fields. The results show that the sample instability problem can be overcome, enabling the use of fourth generation synchrotron sources for BCDI to their full potential.

Published
2020
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17. Tailoring the efficiency of porphyrin molecular frameworks for the electroactivation of molecular N2.

Author

Romero-Angel, María, Amrine, Roumayssa, Ávila-Bolívar, Beatriz, Almora-Barrios, Neyvis, Ganivet, Carolina R., Padial, Natalia M., Montiel, Vicente, Solla-Gullón, José, Tatay, Sergio, and Martí-Gastaldo, Carlos

Abstract

The combination of compositional versatility and topological diversity for the integration of electroactive species into high-porosity molecular architectures is perhaps one of the main appeals of metal–organic frameworks (MOFs) in the field of electrocatalysis. This premise has attracted much interest in recent years, and the results generated have also revealed one of the main limitations of molecular materials in this context: low stability under electrocatalytic conditions. Using zirconium MOFs as a starting point, in this work, we use this stability as a variable to discriminate between the most suitable electrocatalytic reaction and specific topologies within this family. Our results revealed that the PCN-224 family is particularly suitable for the electroreduction of molecular nitrogen for the formation of ammonia with faradaic efficiencies above 30% in the presence of Ni2+ sites, an activity that improves most of the catalysts described. We also introduce the fluorination of porphyrin at the meso position as a good alternative to improve both the activity and stability of this material under electrocatalytic conditions. [ABSTRACT FROM AUTHOR]

Published
2024
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19. List of contributors

Author

Anwar, M.N., primary, Assadi, Aymen Amine, additional, Ávila-Bolívar, Beatriz, additional, Blamo, B.J., additional, Chakrabortty, Sankha, additional, Chakraborty, Prasenjit, additional, De, Dinesh, additional, de Lima, Jeane Estela Ayres, additional, de Souza, Michèle Oberson, additional, Fan, Zhanxi, additional, García-Cruz, Leticia, additional, Hasan, Siti Zubaidah, additional, Humayun, A., additional, Isahak, Wan Nor Roslam Wan, additional, Kanzariya, Dashrathbhai B., additional, Khalil, Munawar, additional, Lashgari, Mohsen, additional, Ligabue, Rosane Angélica, additional, Loganathan, Sivachandiran, additional, Long, Jinlin, additional, Miah, Abu Taleb, additional, Monteiro, Wesley Formentin, additional, Montiel, Vicente, additional, Muthu Mareeswaran, Paulpandian, additional, Nayak, Jayato, additional, Pal, Parimal, additional, Pal, Tapan K., additional, Pires, Jéssica Pereira, additional, Ridwan, Muhammad, additional, Ruj, Biswajit, additional, Senthilkumaran, Marimuthu, additional, Sharma, Vivekanand, additional, Solla-Gullón, José, additional, Vieira, Michele Oliveira, additional, Wang, Z.J., additional, Yu, Jinli, additional, Yunarti, Rika Tri, additional, Zhang, Hongwen, additional, Zhang, Zhicheng, additional, and Zhu, Yating, additional

Published
2021
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24. Direct measurement of the hydrogen adsorption entropy on shape-controlled Pt nanoparticles using electrochemical microcalorimetry.

Author

Botello, Luis E., Schönig, Marco, Solla-Gullón, José, Climent, Víctor, Feliu, Juan M., and Schuster, Rolf

Abstract

Platinum nanoparticles are indispensable in electrochemical applications, e.g., for the generation and usage of green hydrogen. Therefore, understanding the properties of these materials before and during operation is of crucial research interest. However, their investigation is complicated by the variety of adjustable parameters under operating conditions. Researchers thus often revert to studying model systems, like single crystal Pt surfaces, yet it is not always clear how gained insights translate to actual applications. Conducting comprehensive physico-chemical studies on nanoparticles with preferential shapes could help bridge this gap. In this contribution, we use electrochemical microcalorimetry to investigate hydrogen adsorption on different shape-controlled platinum nanoparticles (quasi-spheres, cubes and octahedrons). From this method, we obtain the entropy of the adsorbed hydrogen on the different particles, which we aim to relate to its binding condition with the surface. This quantity often serves as a descriptor for the catalytic performance in the hydrogen evolution reaction. We show that the entropy of adsorption on the particles with different geometries is in good agreement with the adsorption on the single crystal sites related to the respective faces of the particles, by a comparison with entropy values obtained on platinum single crystals using the electrocapillary equation. The consistency between both methods opens possibilities for further research on analogous surfaces. The study is completed by investigating the effect of roughening of the particle surface by continuously cycling the potential into the platinum oxidation region. This enables the investigation of adsorbed hydrogen under more realistic conditions. [ABSTRACT FROM AUTHOR]

Published
2024
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30. Revealing the Intrinsic Restructuring of Bi2O3Nanoparticles into Bi Nanosheets during Electrochemical CO2Reduction

Author

Ávila-Bolívar, Beatriz, Lopez Luna, Mauricio, Yang, Fengli, Yoon, Aram, Montiel, Vicente, Solla-Gullón, José, Chee, See Wee, and Roldan Cuenya, Beatriz

Abstract

Bismuth is a catalyst material that selectively produces formate during the electrochemical reduction of CO2. While different synthesis strategies have been employed to create electrocatalysts with better performance, the restructuring of bismuth precatalysts during the reaction has also been previously reported. The mechanism behind the change has, however, remained unclear. Here, we show that Bi2O3nanoparticles supported on Vulcan carbon intrinsically transform into stellated nanosheet aggregates upon exposure to an electrolyte. Liquid cell transmission electron microscopy observations first revealed the gradual restructuring of the nanoparticles into nanosheets in the presence of 0.1 M KHCO3without an applied potential. Our experiments also associated the restructuring with solubility of bismuth in the electrolyte. While the consequent agglomerates were stable under moderate negative potentials (−0.3 VRHE), they dissolved over time at larger negative potentials (−0.4 and −0.5 VRHE). OperandoRaman spectra collected during the reaction showed that under an applied potential, the oxide particles reduced to metallic bismuth, thereby confirming the metal as the working phase for producing formate. These results inform us about the working morphology of these electrocatalysts and their formation and degradation mechanisms.

Published
2024
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45. High index modulation in reflection holograms using nanoparticle

Author

García-Vázquez, José Carlos, Ramirez, Manuel G., Berramdane, Kheloud, Solla-Gullón, José, Morales-Vidal, Marta, Lloret, Tomás, Pascual, Inmaculada, Universidad de Alicante. Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías, Universidad de Alicante. Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante. Instituto de Electroquímica, Holografía y Procesado Óptico, and Electroquímica Aplicada y Electrocatálisis

Subjects
Holographic materials, Reflection holography, Platinum nanoparticles, Física Aplicada, Química Física, Photopolymer, Óptica
Abstract

Unslanted reflection gratings has been stored in an acrylate-poly(vinyl alcohol) based photopolymer. The diffraction efficiency has been increased doping the photopolymer with platinum (Pt) nanoparticles. This research was funded by Ministerio de Ciencia, Innovación y Universidades, Spain, under project PID2019-106601RB-I00; Generalitat Valenciana, Spain, under projects CDEI-GENT/2018/024, PROMETEO/2021/006, and IDIFEDER/2021/014 (co-funded by European Union through the FEDER Programme); Universidad de Alicante, Spain. Predoctoral Fellowship UAFPU20-23.

Published
2022

46. Autonomous Electrochemical System for Ammonia Oxidation Reaction Measurements at the International Space Station

Author

Cabrera, Carlos, primary, Morales-Navas, Camila, additional, Martinez, Roberto Rodriguez, additional, Vidal-Iglesias, Francisco, additional, Peña-Duarte, Armando, additional, Soto-Pérez, Joesene, additional, Trinidad-Pérez, Pedro, additional, Solla-Gullón, José, additional, Tzvetkov, Toshko, additional, Smotkin, Eugene, additional, Nicolau, Eduardo, additional, Feliu, Juan, additional, and Doan, Jonathan, additional

Published
2022
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49. Refection gratings stored in a nanoparticle-doped photopolymer

Author

García-Vázquez, José Carlos, Ramirez, Manuel G., Berramdane, Kheloud, Solla-Gullón, José, Morales-Vidal, Marta, Lloret, Tomás, Pascual, Inmaculada, Universidad de Alicante. Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante. Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías, Universidad de Alicante. Instituto Universitario de Electroquímica, Holografía y Procesado Óptico, and Electroquímica Aplicada y Electrocatálisis

Subjects
Holographic materials, Holographic gratings, Física Aplicada, Photopolymers, Química Física, Nanoparticle-doped photopolymers, Óptica
Abstract

Nowadays, the study and optimization of volume holography reflection gratings stored in environmentally compatible photopolymers has a great interest since they can be used as holographic optical elements. One of the main advantages of reflection holograms is that they can be reconstructed using white light. This allows to develop holographic sensors. Unslanted reflection holograms have been stored in an acrylate-poly(vinyl alcohol) based photopolymer development in our research group. With the main objective of increasing the diffraction effciency of reflection holograms, a series of chemical modifcations have been introduced in the same acrylated-based photopolymer. Specifcally, this material has been doped with Platinum nanoparticles (Pt-NP), increasing the refractive index modulation in the recorded diffraction gratings. This research was funded by Universidad de Alicante (UAFPU20-23); Generalitat Valenciana (CIDEXG/2022/60, CDEIGENT/2018/024, IDIFEDER/2021/014, PROMETEO/2021/006); Ministerio de Ciencia e Innovación (PID2019-106601RB-I00).

Published
2022

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