Artículos (Instituto de Ciencia de Materiales de Sevilla (ICMS) – CIC Cartuja)
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Artículo Microstructural control by freeze-casting of CaO architectures for improved and stable thermochemical energy storage performance(Elsevier, 2025-07-30) Amghar, Nabil; Ivorra-Martinez, Juan; Perejón Pazo, Antonio; Hanaor, Dorian; Gurlo, Aleksander; Ramírez Rico, Joaquín; Pérez Maqueda, Luis Allan; Sánchez Jiménez, Pedro Enrique; Química Inorgánica; Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). EspañaThis study investigates the development of porous calcium-based monoliths via freeze-casting (FC) as a novel approach for thermochemical energy storage, particularly within the Calcium Looping (CaL) process. The freeze-casting technique enabled the fabrication of scaffolds with controlled porosity using polyvinyl alcohol (PVA) as a binder. Experimental results demonstrated that freeze-cast monoliths exhibited superior multicycle performance under various carbonation and calcination conditions. The FC-CaCO3 monolith achieved the highest residual conversion of 68.1 % under mild vacuum calcination conditions (780 °C, 0.1 bar CO2), significantly surpassing other configurations. Tests conducted in an inert atmosphere also yielded favorable results, with a conversion of 56.1 %, outperforming equivalent raw powder samples. The enhanced performance is attributed to improved CO2 interaction with the porous structure, mitigating sintering effects and preserving active surface area. Morphological observations by X-ray tomography and SEM confirmed limited particle sintering after multiple cycles, maintaining a reactive surface that supported consistent conversion rates. The pore size distribution of the material evolves upon cycling resulting in an increased microporosity, while the pore network maintains a low tortuosity (τ ~ 1.5–2.0). The addition of dopants such as ZrO2 and SiO2 did not enhance performance, as the monoliths' inherent structure provided sufficient stability. These findings highlight freeze-casting as a promising method for creating advanced porous materials suitable for energy storage applications.Artículo Graphene exfoliation in cyrene for the sustainable production of microsupercapacitors(Institute of Physics Publishing Ltd., 2025-04-22) Moreira, Pedro; Carvalho, Davide; Abreu, Rodrigo; Alba Carranza, María Dolores; Ramírez Rico, Joaquín; Fortunato, Elvira; Martins, Raúl A.; Pinto, Joana V.; Carlos, Emanuel; Coelho, João; Física de la Materia Condensada; Fundaçao para a Ciencia e a Tecnologia (FCT); Junta de Andalucía; European UnionGraphene and its composites have attracted much attention for applications in energy storage systems. However, the toxic solvents required for the exfoliation process have hampered the exploitation of its properties. In this work, graphene dispersions are obtained via liquid phase exfoliation (LPE) of graphite in cyrene, an environmentally friendly solvent with solubility parameters like those of N-methyl-2-pirrolidone. The obtained dispersions with a concentration of 0.2 mg ml−1 comprised multilayered graphene sheets with lateral sizes in the hundreds of nanometers, as confirmed by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Mixing the obtained dispersions with ethanol made it possible to collect the graphene, which was redispersed in 2-Propanol. This active material was used to fabricate supercapacitor electrodes using a scalable spray deposition method on carbon nanotube (CNT) current collectors with the aid of vinyl masks. The device, tested with a PVA/LiCl gel electrolyte, achieved a specific capacitance of 3.4 mF cm−2 (0.015 mA cm−2). In addition, the devices show excellent cycling stability (>10 000 cycles at 0.5 mA cm−2) and good mechanical properties, losing less than 10% of initial capacitance after 1000 bending cycles. This work demonstrates the adaptability of liquid-phase exfoliation to produce graphene sustainably, providing the proof-of-concept for further 2D materials processing and green microsupercapacitor (MSC) fabrication.Artículo Ion Mobility and Segregation in Seed Surfaces Subjected to Cold Plasma Treatments(American Chemical Society, 2025-02-24) Perea Brenes, Álvaro; Ruiz Pino, Natalia; Yubero, Francisco; Garcia, José Luis; Rodríguez González-Elipe, Agustín; Gómez Ramírez, Ana María; Prados Montaño, Antonio; López Santos, Carmen; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Universidad de Sevilla. Departamento de Física Aplicada I; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE); Universidad de Sevilla; Junta de AndalucíaPlasma treatment of seeds is an efficient procedure to accelerate germination, to improve initial stages of plant growth, and for protection against pathogen infection. Most studies relate these beneficial effects with biochemical modifications affecting the metabolism and genetic growth factors of seeds and young plants. Using barley seeds, in this work, we investigate the redistribution of ions in the seed surface upon their treatment with cold air plasmas. In addition, we investigate the effect of plasma in the lixiviation of ions through the seeds’ hull when they are immersed in water. Ion redistribution in the outer layers of air plasmatreated seeds has been experimentally determined through X-ray photoelectron spectroscopy analysis in combination with in-depth chemical profiling with gas cluster ion beams. The results show that in the shallowest layers of the seed hull (at least up to a depth of ∼100 nm) there is an enrichment of K+ and Ca2+ ions, in addition to changes in the O/C and N/C atomic ratios. These data have been confirmed by the electron microscopy/fluorescence analysis of seed cuts. Observations have been accounted for by a Monte Carlo model, simulating the electrostatic interactions that develop between the negative charge accumulated at the seed surface due to the interaction with the plasma sheath and the positive ions existing in the interior. Furthermore, it is shown that upon water immersion of plasma-treated seeds mobilized ions tend to lixiviate more efficiently than in pristine seeds. The detection of a significant concentration of NO3− anions in the water has been attributed to a secondary reaction of nitrogen species incorporated into the seeds during plasma exposure with reactive oxygen species formed on their surface during this treatment. The implications of these findings for the improvement of the germination capacity of seeds are discussed.Artículo Comparing 3He content in magnetron sputtered and implanted targets for nuclear studies(Springer, 2025-05-25) Pilotto, E,; Ferrer Fernández, Francisco Javier; Akhmadaliev, S.; Fernández, A.; Gadea, A.; Camacho, J.; Valiente Dobón, J. J.; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Ministerio de Ciencia e Innovación (MICIN). España; European Union (UE); Agencia Estatal de Investigación. España; Generalitat Valenciana3He targets are a valuable tool in nuclear physics, particularly for studying nuclear structure and dynamics via direct reactions in inverse kinematics. However, they are often prone to degradation under intense beam irradiation and have insufficient 3He content for use with lowintensity exotic beams. In a recent AGATA experiment at LNL, designed to study the astrophysically relevant lifetime of a 15O excited state, two types of 3He targets were tested. One was produced using ion implantation and the other with a novel magnetron sputtering technique, in both cases on Au substrates. Following irradiation with a stable 16O beam, they were characterized using Nuclear Reaction Analysis (NRA) and Elastic Recoil Detection Analysis (ERDA). Results demonstrated that, under the here used fabrication conditions, sputtered targets present a higher 3He content, while implanted ones exhibit thinner profiles. This highlights the possibilities and complementarity of these targets, suggesting their tailored use for future experimental campaigns.Artículo Gas temperature equation in a high-frequency argon plasma column at low pressures(American Institute of Physics, 2002-01) Palmero Acebedo, Alberto; Cotrino Bautista, José; Barranco Quero, Ángel; Rodríguez González-Elipe, Agustín; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Comisión Interministerial de Ciencia y Tecnología (CICYT). España; European Union (UE)Using a collisional-radiative model and taking into account an energy balance equation in a surface-wave-produced and -sustained argon plasma, it is possible to obtain the dependence of the gas temperature on the plasma parameters. If only heat conduction and radiative losses are considered for the neutral system, as well as the interaction with the electrons, the plasma parameters that determine the gas temperature will be the elastic absorbed power per electron and the electron number density. In a first approximation the axial dependence of the neutral gas temperature can be considered lineal with the product of these two parameters.Artículo Collisional radiative model of an argon atmospheric capillary surface-wave discharge(American Institute of Physics, 2004-11-03) Yanguas Gil, A.; Cotrino Bautista, José; Rodríguez González-Elipe, Agustín; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Dirección General de Investigación Científica y Técnica (DGICYT). EspañaThe characteristics of a microwave surface-wave sustained plasma operated at atmospheric pressure in an open-ended dielectric tube are investigated theoretically as a first step in the development of a self-consistent model for these discharges. The plasma column is sustained in flowing argon. A surface-wave discharge that fills the whole radial cross section of the discharge tube is considered. With experimental electron temperature profiles [García et al., Spectrochim. Acta, Part B 55, 1733 (2000)] the numerical model is used to test the validity of the different approximations and to study the influence of the different kinetic processes and power loss mechanisms on the discharge.Artículo Impact of Tb4+ and morphology on the Thermal Evolution of Tb-doped TiO2 Nanostructured Hollow Spheres and Nanoparticles(Elsevier, 2021-02-05) Colomer, M. T.; Rodríguez, E.; Morán Pedroso, María; Vattier Lagarrigue, María Florencia; Andrés, A. de; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Union (UE)Tb-doped TiO2 hollow spheres (HSs) in the range 0.0-2.0 at.% have been,synthesized by the first time to the best of our knowledge. The HSs are compared with,nanoparticles (NPs) to evaluate the impact of morphology on their physicochemical and,photoluminescence (PL) behavior upon increasing calcination temperature. After,calcination at 550ºC, the particles are anatase with a primary average size of 10.0 ± 0.2,nm for the NPs and 12.0 ± 0.2 nm for those that form the micron sized hollow spheres of,1.8 µm diameter and ca. 64 nm shell thickness. The temperature of the anatase–rutile,transition is found to be strongly dependent on the presence of Tb as well as on,morphology. Contrarily to the usual stabilization of anatase when doping with trivalent,rare-earth ions, the transition temperature is reduced when doping with Tb. The rutile,phase is further favored for the HSs compared to the NPs probably related to the low,density of the HSs and/or a more efficient packing of the nanoparticles that form those,spheres with respect to the packing of the NPs. A slight unit-cell volume decrease for the,anatase structure is observed upon Tb doping, in both the NPs and in the HSs, contrary to,the expected increment due to the larger ionic radius of Tb3+ compared to Ti4+,. In addition,,2,the intensity of the characteristic f-f Tb3+ emission bands is extremely weak both in the,anatase and rutile phases. The transition is accompanied with the emergence of an infrared,emission band centered at 810 nm related to the formation of defects during the structural,transformation providing deep levels in the gap that partly quench the f-f emissions in the,rutile phase. The results are consistent with the presence of Tb in both +3 and +4 valence,states. XPS measurements confirmed the presence of Tb3+ as well as of Tb4+ in both HSs,and NPs with a Tb4+ fraction that increases with increasing Tb doping. The large fraction,of Tb4+ present in the samples originates the weak f-f emission intensity, the slight,decrease of the cell parameters and the destabilization of the anatase phaseArtículo Quantification of the H Content in Diamondlike Carbon and Polymeric Thin Films by Reflection Electron Energy Loss Spectroscopy(American Institute of Physics, 2005) Yubero, Francisco; Rico, Víctor; Espinós Manzano, Juan Pedro; Cotrino Bautista, José; Rodríguez González-Elipe, Agustín; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Ministerio de Educación y Ciencia (MEC). EspañaA nondestructive method to determine the hydrogen content at the surface of diamondlike carbon and polymeric thin films is proposed. The method relies on the analysis of the elastic peak produced by backscattering of electrons from the hydrogen atoms present at the sample surface. Quantitative analysis of the H content at the surface is achieved through use of a phenomenological sensitivity factor for elastic electron backscattering by H atoms with respect to other atoms present at the surface of reference polymeric samples. The validity of the method is checked with elastic recoil detection measurements and infrared spectroscopy analysis of the same samples. The accuracy of the method in the determination of H content at the sample surface is estimated to be ±10%.Artículo Solid-state spectroscopic, thermokinetics and thermal analysis of aceclofenac coordination complexes with lanthanum and gadolinium(Soc Brasileira Quimica, 2024-05-24) Melo, Laís D. S. M. K; Carvalho, Cláudio T.; Sánchez Jiménez, Pedro Enrique ; Sequinel, Thiago; Perejón Pazo, Antonio; Pérez Maqueda, Luis Allan ; Colman, Tiago A. D.; Universidad de Sevilla. Departamento de Química Inorgánica; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Brasil; Finaciadora de Estudos e Projetos (FINEP). BrasilIn recent years, the field of coordination chemistry has experienced a surge in interest regarding the synthesis and characterization of coordination complexes for diverse applications. This study is dedicated to investigating coordination compounds resulting from the interaction of nonsteroidal anti-inflammatory drugs (NSAIDs) with metal ions. The study research places significant emphasis on understanding the stability and thermal behavior of these coordination compounds. The utilization of thermoanalytical techniques is crucial in achieving this goal. Thermal analysis and thermokinetics provide valuable insights into the underlying mechanisms, kinetics, and energetics of these reactions, thereby facilitating the optimization of synthesis procedures. The research employs concurrent techniques, namely thermogravimetric analysis (TG) and differential scanning calorimetry (DSC), to explore the thermal stability and decomposition pathways of these coordination compounds. Thermokinetic models and optimization methodologies are subsequently applied to identify key reaction parameters. The primary aim of this research is to unveil the thermal behavior, stability, and reaction kinetics of aceclofenac coordination compounds, thus contributing significantly to the understanding of thermokinetics and thermal analysis in the domain of coordination chemistry. Specifically, this study is focused on aceclofenac coordination complexes involving lanthanum and gadolinium, with the ultimate goal of advancing the field of coordination chemistryArtículo Integrated CO2 capture and dynamic catalysis for CO2 recycling in a microbrewery(Elsevier, 2025-02) Merkouri, Loukia Pantzechroula; Bobadilla Baladrón, Luis Francisco; Martín Espejo, Juan Luis; Odriozola Gordón, José Antonio; Penkova, Anna Dimitrova; Torres Sempere, Guillermo; Ramírez Reina, Tomás; Short, Michael; Duyar, Melis S.; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Union (UE)In this study, we used fermentation off-gases from a brewery for integrated CO2 capture and utilisation in order to produce CH4 with a dual-function material (DFM) containing NiRu as catalyst and dispersed CaO as adsorbent. CH4 was produced from captured CO2 via 2 pathways (fast and slow), proceeding through formyl intermediates according to the operando DRIFTS-MS results. The NiRuCa DFM showed a stable CH4 capacity over 8 cycles (105 μmol/gDFM) with fermentation off-gases being used as a CO2 capture feed. H2O and O2, which were present in small amounts in the emissions feed, resulted in the passivation of Ni in the form of a NiO layer and hence, the DFM did not undergo excessive oxidation and deactivation. This work constitutes a first in terms of validating the use of DFMs with real industrial emissions, and it directly correlates the DFM activity performance with its reaction mechanism and intermediate species.Artículo Textile microfibers valorization by catalytic hydrothermal carbonization toward high-tech carbonaceous materials(American Association for the Advancement of Science, 2024-11-18) Parrilla Lahoz, Silvia; Zambrano, Marielis C.; Pawlak, Joel J.; Venditti, Richard A.; Ramírez Reina, Tomás; Odriozola Gordón, José Antonio; Duyar, Melis S.; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Next Generation EuropeMicroplastics fibers shed from washing synthetic textiles are released directly into the waters and make up 35% of primary microplastics discharged to the aquatic environment. While filtration devices and regulations are in development, safe disposal methods remain absent. Herein, we investigate catalytic hydrothermal carbonization (HTC) as a means of integrating this waste (0.28 million tons of microfibers per year) into the circular economy by catalytic upcycling to carbon nanomaterials. Herein, we show that cotton and polyester can be converted to filamentous solid carbon nanostructures using a Fe-Ni catalyst during HTC. Results revealed the conversion of microfibers into amorphous and graphitic carbon structures, including carbon nanotubes from a cotton/polyethylene terephthalate (PET) mixture. HTC at 200°C and 22 bar pressure produced graphitic carbon in all samples, demonstrating that mixed microfiber wastes can be valorized to provide potentially valuable carbon structures by modifying reaction parameters and catalyst formulation.Artículo The impact of interfacial quality and nanoscale performance disorder on the stability of alloyed perovskite solar cells(Nature Research, 2024-10-30) Frohna, Kyle; Chosy, Cullen; Al-Ashouri, Amral; Scheler, Florian; Chiang, Yu-Hsien; Dubajic, Milos; Anaya Martín, Miguel; Stranks, Samuel D.; Universidad de Sevilla. Departamento de Física de la Materia Condensada; European Union (UE). H2020; Engineering Physical Sciences Research Council (EPSCR) U. K.Microscopy provides a proxy for assessing the operation of perovskite solar cells, yet most works in the literature have focused on bare perovskite thin flms, missing charge transport and recombination losses present in full devices. Here we demonstrate a multimodal operando microscopy toolkit to measure and spatially correlate nanoscale charge transport losses, recombination losses and chemical composition. By applying this toolkit to the same scan areas of state-of-the-art, alloyed perovskite cells before and after extended operation, we show that devices with the highest macroscopic performance have the lowest initial performance spatial heterogeneity—a crucial link that is missed in conventional microscopy. We show that engineering stable interfaces is critical to achieving robust devices. Once the interfaces are stabilized, we show that compositional engineering to homogenize charge extraction and to minimize variations in local power conversion efciency is critical to improve performance and stability. We fnd that in our device space, perovskites can tolerate spatial disorder in chemistry, but not charge extraction.Artículo Revisiting Stability Criteria in Ball-Milled High-Entropy Alloys: Do Hume–Rothery and Thermodynamic Rules Equally Apply?(Willey, 2024-10-07) Blázquez Gámez, Javier Sebastián; Manchón Gordón, Alejandro F.; Vidal Crespo, Antonio; Caballero Flores, Rafael; Ipus Bados, Jhon Jairo; Conde Amiano, Clara Francisca; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Junta de Andalucía; Universidad de SevillaStability descriptors for the formation of solid solutions can be divided into two categories: inspired by Hume–Rothery rules (HRR) and derived from thermodynamic approaches. Herein, HRRs are extended from binary to high-entropy alloys (HEAs) focusing on compositions prepared by ball milling. Parameters describing stability criteria are interrelated and implicitly account for the microstrains’ storage energy, more determinant than entropy increase in stabilization of HEAs and more effective in bcc structures than close-packed ones (fcc and hcp). An effective temperature, Teff, is defined as the ratio between increase in metallic bonding energy of solid solutions with respect to segregated pure constituents and configurational entropy. This versatile parameter is used as a threshold for stabilization of HEAs at equilibrium and out of equilibrium. When Teff is below room temperature, HEA would be stable at equilibrium. When Teff is below melting temperature, HEA would be obtained by rapid quenching. Limitations related to electronegativity differences remain valid in mechanically alloyed solid solutions. However, ball milling broadens the allowed differences in atomic size to form HEA. Moreover, thermodynamic criteria can be surpassed in these systems, allowing the formation of single-phase solid solutions beyond the compositional range predicted by those criteria.Artículo Navigating the Legislative Interventions, Challenges, andOpportunities in Revolutionizing Textile Upcycling/RecyclingProcesses for a Circular Economy(American Chemical Society (ACS), 2024) Saif, Maria; Blay Roger, José Rubén; Zeeshan, Muhammad; Bobadilla Baladrón, Luis Francisco; Ramírez Reina, Tomás; Nawaz, Muhammad Asif; Odriozola Gordón, José Antonio; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; European Union (UE)Embracing a circular economy in the textile industry represents a crucial steptoward sustainability, where fashion and textile sectors contribute significantly to CO2emissions. However, transitioning from a linear “take-make-waste” model to circularity,poses multifaceted challenges, that highlight the staggering volume of annual textile wastesurpassing industry predictions, thus emphasizing the urgent need for comprehensivestrategies. Despite advancements in recycling technologies, challenges persist in collectingand sorting textile waste, where fragmentation in waste management and recycling processeshinders effective management of post-consumer waste. Addressing these challenges demandselevated efforts in collection, sorting, and pre-processing, alongside regulatory interventions todrive enhanced waste collection and circular business models. Efforts are underway to promotesustainable textile recycling, with initiatives like the EU’s Sustainable and Circular TextilesStrategy aiming to reduce reliance on virgin resources. However, achieving a circular textilemarket in the near future requires collaborative action and innovative solutions. Thoughchallenges in scaling and technological limitations still remain, recent breakthroughs in textile-recycling technologies offer promise,signaling a shift toward scalable and sustainable alternatives to virgin fibers, where bio-based chemical processes, andthermochemical recycling processes present transformative opportunities. Where, bold scaling targets, collaborative efforts, andshort-term funding support narrated in this perspective article are imperative to accelerate the transition to a circular textileeconomy, thus delving into the pivotal role of textile recycling, tracing the evolution of recycling technologies, and addressing criticalchallenges hindering widespread adoption.Artículo Interplay between connectivity and passivating agents in perovskite quantum dot networks(Royal Society of Chemistry, 2024-10-02) Morán Pedroso, María; Tiede, David O.; Romero-Pérez, Carlos; Calvo, Mauricio E.; Galisteo López, Juan F.; Míguez, Hernán; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Unión Europea NextGeneration; Junta de AndalucíaIntroducing quantum dots (QDs) as the active element of an optoelectronic device demands its incorporation in the shape of interconnected arrays that allow for some degree of electronic coupling in order to inject/extract charge carriers. In doing so, beyond reducing the degree of quantum confinement, carriers are exposed to an enhanced defect landscape as they can access adjacent QDs, which is at the origin of the strong reduction of photoluminescence observed in QD solids when compared to that of the isolated QDs. In this work we demonstrate how a proper defect passivating strategy or atmospheric treatment can greatly enhance charge diffusion in a QD film, needed for an optimal carrier injection/extraction demanded for optoelectronic applications, and also improved its stability against external radiation. From a fundamental perspective, we provide evidence showing that trap density distribution, rather than QD size distribution, is mostly responsible for the observed variations in emission decay rates present in the QD networks under analysis.Artículo Better together: Monolithic halide perovskite@metal-organic framework composites(Cell Press, 2024-12-04) Ávila, Elena; Salway, Hayden; Ruggeri, Edoardo; Çamur, Ceren; Rampal, Nakul; Doherty, Tiarnan A. S.; Moseley, Oliver D. I.; Stranks, Samuel D.; Fairen Jiménez, David; Anaya Martín, Miguel; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. EspañaA few years ago, we theoretically studied the production of a stellar neutron spectrum at kT 30 keV using a shaped proton beam impinging on a thick lithium target. Here, we first measure the proton distribution to better control the produced neutron spectrum. Then, we measure the forward-emitted angle-integrated neutron spectrum of the 7Li(p,n)7Be reaction via time-of-flight neutron spectrometry with such proton distribution. The result resembles a stellar neutron spectrum at kT 30 keV. This method avoids in activation experiments the need for spectrum correction. In the case of spherical samples, no knowledge of the crosssection of the isotope being measured by activation would be necessary. Therefore, the present method is of interest for isotopes with unknown or poorly known cross-sections, such as branching points in astrophysics. The key point of our method is the experimental control of the proton distribution that impinges on the lithium target.
Artículo Design of catalysts for selective CO2 hydrogenation(Springer Nature, 2025-02-27) Ye, Runping; Ding, Jie; Ramírez Reina, Tomás; Duyar, Melis Seher; Li, Haitao; Luo, Wenhao; Zhang, Rongbin; Fan, Maohong; Feng, Gang; Sun, Jian; Liu, Jian; Universidad de Sevilla. Departamento de Química Inorgánica; Natural Science Foundation of Jiangxi Province; National Natural Science Foundation of China; National Key Research and Development Program of ChinaCO2 hydrogenation with green hydrogen is a practical approach for the reduction of CO2 emissions and the generation of high-value-added chemicals. Generally, product selectivity is affected by the associated reaction mechanisms, internal catalyst identity and structure, and external reaction conditions. Here we examine typical CO2 hydrogenation reaction pathways, which can provide insight useful for the atomic-level design of catalysts. We discuss how catalyst chemical states, particle sizes, crystal facets, synergistic effects and unique structures can tune product selectivity. Different catalysts, such as Fe-, Co-, Ni-, Cu-, Ru-, Rh-, Pd-based and bifunctional structured catalysts, and their influence on CO2 hydrogenation products (such as CO, methane, methanol, ethanol and light olefins) are discussed. Beyond catalyst design, emerging catalytic reaction engineering methods for assisting the tuning of product selectivity are also discussed. Future challenges and perspectives in this field are explored to inspire the design of next-generation selective CO2 hydrogenation processes to facilitate the transition towards carbon neutrality. (Figure presented.)Artículo Tailoring of Self-Healable Polydimethylsiloxane Films for Mechanical Energy Harvesting(American Chemical Society, 2024) Ghosh, K.; Morgan, A.; García Casas, Xabier; Kar-Narayan, S.; Universidad de Sevilla. Departamento de Electrónica y Electromagnetismo; European Union (UE). H2020; Newton International Fellowships. U.K.; Ministerio de Ciencia e Innovación (MICIN). EspañaTriboelectric nanogenerators (TENGs) have emerged as potential energy sources, as they are capable of harvesting energy from low-frequency mechanical actions such as biological movements, moving parts of machines, mild wind, rain droplets, and others. However, periodic mechanical motion can have a detrimental effect on the triboelectric materials that constitute a TENG device. This study introduces a self-healable triboelectric layer consisting of an Ecoflex-coated self-healable polydimethylsiloxane (SH-PDMS) polymer that can autonomously repair mechanical injury at room temperature and regain its functionality. Different compositions of bis(3-aminopropyl)-terminated PDMS and 1,3,5-triformylbenzene were used to synthesize SH-PDMS films to determine the optimum healing time. The SH-PDMS films contain reversible imine bonds that break when the material is damaged and are subsequently restored by an autonomous healing process. However, the inherent stickiness of the SH-PDMS surface itself renders the material unsuitable for application in TENGs despite its attractive self-healing capability. We show that spin-coating a thin layer (≈32 μm) of Ecoflex on top of the SH-PDMS eliminates the stickiness issue while retaining the functionality of a triboelectric material. TENGs based on Ecoflex/SH-PDMS and nylon 6 films show excellent output and fatigue performance. Even after incisions were introduced at several locations in the Ecoflex/SH-PDMS film, the TENG spontaneously attained its original output performance after a period of 24 h of healing. This study presents a viable approach to enhancing the longevity of TENGs to harvest energy from continuous mechanical actions, paving the way for durable, self-healable mechanical energy harvesters.Artículo Size-tailored Ru nanoparticles deposited over γ-Al 2 O 3 for the CO 2 methanation reaction(Elsevier, 2019-07-31) Navarro Jaén, Sara; Navarro de Miguel, Juan Carlos; Bobadilla Baladrón, Luis Francisco; Centeno Gallego, Miguel Ángel; Laguna Espitia, Óscar Hernando; Odriozola Gordón, José Antonio; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Economía y Competitividad (MINECO). EspañaBy means of the polyol method, a series of 5 wt% Ru/Al 2 O 3 catalysts was synthesized controlling the particle size of the ruthenium species. The physico-chemical characterization demonstrated the successful particle size control of the Ru species, in such a way that higher the Ru/PVP ratio, higher the Ru particle size. Moreover, there are evidences that suggest preferential growth of the RuO 2 clusters depending on the Ru/PVP ratio. Regarding the catalytic activity during the CO 2 methanation, the total conversion and the CH 4 yield increased with the particle size of Ru. Nevertheless, a considerable enhancement of the catalytic performance of the most active system was evidenced at 4 bar, demonstrating the improvement of the thermodynamics (superior total conversion) and kinetics (superior reaction rate) of the CO 2 methanation at pressures above the atmospheric one. Finally, the in situ DRIFTS study allowed to establish that CO 2 was dissociated to CO* and O* species on the metallic Ru particles, followed by the consecutive hydrogenation of CO* towards CHO*, CH 2 O*, CH 3 O*, and finally CH 4 molecules, which were further desorbed from the catalyst. Thus from the mechanistic point of view, a suitable particle size of the Ru nanoparticles along with the high-pressure effects results in the enhancement of the availability of hydrogen and consequently in the formation of CH x O species that enhance the cleavage of the C–O bond, which is the rate-determining step of the overall CO 2 methanation process.Artículo Stability and Performance of BTC-based MOFs for Environmental Applications(Elsevier, 2024) Rodríguez Esteban, Corina; Ayala Espinar, Regla; López Cartes, Carlos; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Junta de AndalucíaTwo series of open metal site MOFs, HKUST-1 and MIL-100(Fe), have been successfully prepared using different methods of synthesis. Their features depend on the synthetic route as well as their role play in different environmental applications. The stability and performance of these BTC-based MOFs have been tested bearing in mind Congo Red (CR) removal, humidity adsorption and iodine capture and release. HKUST-1 and MIL-100(Fe) samples could offer a remarkable role in the adsorption of CR from aqueous solutions. However, the lability of HKUST-1 in water is revealed as a drawback for its reutilization in both static and agitation conditions. The former contrasts to the stability under ambient moisture. MIL-100(Fe) shows promising properties in both CR adsorption in aqueous solutions and humidity adsorption. Nonetheless, the performance largely depends on the synthesis conditions. Although CR removal is based on surface interaction, there is a relation between the adsorpted quantity and the specific surface area. The size and nature of iodine allows the diffusion in the pores of both HKUST-1 and MIL-100(Fe) MOFs. This way, the uptake of iodine is driving by the porosity and surface area of samples rather than their inherent nature. As a rule, the results of this work indicate that not only is it important the specific nature of the MOF chosen for a given application but also the way in which it has been synthesized and the conditions in which they are used. MIL-100(Fe)-R is revealed as the best suitable candidate to be used as a sorbent for CR in aqueous solutions, moisture and I2 gas.