Scientific Papers in SCI

Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) experiments have been carried out in N-2 and N-2-H2O atmospheres on a Pt-based catalyst physically mixed with an Eu-doped ZrO2 ionic conductor as a function of temperature under realistic conditions of the water gas shift (WGS) reaction. This work aims to demonstrate the significant effect of having active H2O on the ionic conductor surface at reaction temperatures to provide it to Pt metal sites. The ionic conductor, Eu-doped zirconia matrix, presents defects (oxygen vacancies, O-v) that allows upon H2O dissociation the formation of a hydrogen-bonded molecular water layer favoring diffusion through a Grotthuss mechanism below 300 degrees C. In the presence of H2O, the O-v are occupied by hydroxyl species as observed in the Eu 4d spectra, which differentiate two types of Eu oxidation states. The Eu3+-to-Eu2+ atomic ratio increases with the occupancy of the O-v by hydroxyls. Moreover, while the Pt-based catalyst alone is unable to create Pt-OH bonds, the physical mixture of the Pt-based catalyst and the ionic conductor allows the formation of Pt-OH bonds from room temperature up to 300 degrees C. These data demonstrate that the increase in molecular water concentration on the ionic conductor surface up to 300 degrees C acts as a reservoir to provide water to the Pt surface, enhancing the catalyst performance in the WGS reaction, supporting the importance of the surface H2O concentration in the reaction kinetics.

Solid-state oxide ion and proton conductors are garnering significant attention due to their high ionic conductivity and potential applications in a range of electrochemical devices, including solid oxide fuel cells and gas sensors. In this study, we report the influence of partial substitution of La³⁺ in isolated tetrahedral LaVO₄ ceramics with 0.01 mol of alkaline-earth metals Ca²⁺, Sr²⁺ and Ba²⁺ on the phase stability and electrical properties. It was found that acceptor doping effectively enhances mixed oxide ion and proton conductivities, with Sr²⁺ substitution yielding the highest conductivity, achieving ∼10⁻³ S cm⁻¹ at 900 °C under a wet O₂ atmosphere. DFT calculations and ab initio molecular dynamics simulations revealed that protons preferentially form hydrogen bonds with the lattice oxygen near the dopants and migrate through a continuous process of hopping and rotation between inter- and intra-tetrahedral VO₄ groups. Additionally, the existence of oxygen vacancies facilitates the formation of V₂O₇ dimers through sharing corners with adjacent isolated VO₄ tetrahedra, enabling ion exchange through a synergistic mechanism involving V₂O₇ dimer breaking and reforming. This research highlights the critical role of the deformation and rotational flexibility of isolated tetrahedral units in facilitating oxide ion and proton transport, underscoring the potential for developing mixed oxide ion and proton conductors in oxygen vacancy-deficient oxides with tetrahedral-based structures.

The discovery of a set of beads, comprising both Sicilian amber and resin-coated beads in the Middle Bronze Age burial site of Cova del Gegant (Sitges, Barcelona, Spain), has sparked inquiries into whether the coating was intended for imitation or counterfeiting of amber. We assert that human-made materials, such as bead coatings, are intentionally conceived, designed, and crafted to fulfill specific functions. Thus, for an object to effectively fulfill its intended purpose, it must meet particular performance criteria influenced by situational factors. This paper aims to construct an empirically grounded narrative elucidating the development and function of resin-coated bead technology. Our methodology includes a comprehensive quantitative analysis of the coating and beads, an exploration of the interplay between technical choices and situational factors, and an investigation into whether the simulation of sensory performance characteristics played a pivotal role in the concept and design of resin-coated beads. Additionally, we synthesize data to unveil broader patterns related to the crafting and utilization of resin-coated and amber beads across time and space. We have documented resin-coated beads in the Iberian Peninsula from the Neolithic period (5th to 3rd millennia BCE) until at least the Middle Bronze Age (first half of the 2nd millennium BCE), where they coexisted with amber beads. Analysis employing ATR-FTIR and mu-CT imaging has revealed a composite coating comprising pine resin, beeswax, and carotene, adhered to shell beads with bone glue. This composite material represents the earliest known development in human history, unique to the Iberian Peninsula and without parallel in Prehistoric Europe. Our examination of the performance characteristics and functional roles of resin-coated beads suggests their potential as substitutes for amber beads, particularly in regions where amber was scarce or inaccessible. Despite being crafted from commonplace materials, these coated beads exhibit intentional design choices likely aimed at simulating the visual performance characteristics of amber. This deliberate effort, alongside their widespread distribution across time and space, indicates that composite-coated beads held symbolic and social significance akin to amber beads.

There is relevant interest concerning beehives, taking into account climate change and its influence on bees’ behavior. A part of the industrial engineering sector is focusing on beekeeping applications. More specifically, the present study aims to develop a trailer for the transport of beehives adapted to be placed or fixed to a tractor or a vehicle trailer, with the objective of transporting the beehives safely and stably during transhumance. The proposed novel design relates to a trailer that incorporates a device for housing a rectangular section of the beehives, which can be adapted for fixing or housing in a vehicle or in a vehicle trailer. The device comprises a lower support structure, adapted to support a plurality of rectangular sections of beehives stacked horizontally on the lower structure, an upper frame adapted to house the beehives inside, and two or more connecting elements between the lower structure and the upper frame. The connection of the trailer with the device facilitates the loading and unloading of the beehives by mechanical means. The different parts have been designed as individual pieces and then assembly is carried out to achieve the complete design. This method of implementation is because the simulation of individual components is simpler and easier, since if it is carried out through assembly, the type of joint, such as welding, and the length of the weld would have to be indicated at each point of contact between components, along with its thickness and all the necessary parameters. Therefore, in those welding points, fixed fastenings are indicated and so will simplify it. In accordance with the individual creation of each part, its own load simulation has been carried out. Static analyses are performed taking into account structural elements of this proposed design, with restrictions and loads being established. The analysis, including upper bars and supports, has been completed with several situations. Based on stress values, deformations have been determined and calculations evaluated. The trays have been manufactured using flat steel bars and angled bars for the legs and support of the hives.

Water quality and usability are global concerns due to microbial and chemical pollution resulting from anthropogenic activities. Therefore, strategies for eliminating contaminants are required. In this context, the removal and decrease in antibiotic activity (AA) associated with levofloxacin (LEV), using TiO₂ and Ag/TiO₂ catalysts, with and without sunlight and peroxydisulfate, was evaluated. Additionally, the disinfection capacity of catalytic systems was assessed. The catalysts were synthesized and characterized. Moreover, the effect of Ag doping on visible light absorption was determined. Then, the photocatalytic treatment of LEV in water was performed. The materials characterization and EPR analyses revealed that LEV degradation and AA decrease were ascribed to a combined action of solar light, sulfate radical, and photocatalytic activity of the TiO₂-based materials. Also, the primary byproducts were elucidated using theoretical analyses (predictions about moieties on LEV more susceptible to being attacked by the degrading species) and experimental techniques (LC-MS), which evidenced transformations on the piperazyl ring, carboxylic acid, and cyclic ether on LEV. Moreover, the AA decrease was linked to the antibiotic transformations. In addition, the combined system (i.e., light/catalyst/peroxydisulfate) was shown to be effective for E. coli inactivation, indicating the versatility of this system for decontamination and disinfection.

In this piece, we explore the transformative potential of sustainable biofuel production as a solution to the energy crisis and a pivotal element in realizing the environmental and societal ambitions of Society 5.0. Through a critical examination of "bottom-up"and "topdown"strategies for converting bio-feedstocks sourced from anthropogenic activities into renewable fuels, the work underscores the need for innovation in catalysts and process intensification. By highlighting the advances and challenges in harnessing unconventional feedstocks and integrating renewable energy, this work points to a future where biofuels stand as a cornerstone of a sustainable energy landscape. The significance of this discussion extends beyond the technical realm, offering a vision for a circular economy that reduces dependence on fossil fuels, addresses climate change, and promotes global energy security. It calls for a united front among researchers, industry leaders, and policymakers to drive the biofuel sector toward efficiency, scalability, and widespread adoption.

Persistent luminescence materials have applications in diverse fields such as smart signaling, anticounterfeiting, and in vivo imaging. However, the lack of a thorough understanding of the precise mechanisms that govern persistent luminescence makes it difficult to develop ways to optimize it. Here we present an accurate model to describe the various processes that determine persistent luminescence in ZnGa2O4:Cr3+, a workhorse material in the field. A set of rate equations has been solved, and a global fit to both charge/discharge and thermoluminescence measurements has been performed. Our results establish a direct link between trap depth distribution and afterglow kinetics and shed light on the main challenges associated with persistent luminescence in ZnGa2O4:Cr3+ nanoparticles, identifying low trapping probability and optical detrapping as the main factors limiting the performance of ZnGa2O4:Cr3+, with a large margin for improvement. Our results highlight the importance of accurate modeling for the design of future afterglow materials and devices.

This paper deals with the effect of hydroxylated boron nitride nanosheets (BNNS) incorporation on the microstructural and mechanical features of zirconia ceramics. Few-layered BNNS were synthesized via a simple hydroxide-assisted planetary ball milling exfoliation technique. 3 mol% yttria tetragonal zirconia polycrystal (3Y-TZP) with 2.5 vol% BNNS powders were prepared by an environmentally friendly process in water, and spark-plasma sintered at three temperatures to explore the in-situ reduction of the functionalized BNNS. An exhaustive study by (S)TEM techniques was performed to elucidate the influence of the sintering temperature on the matrix and the 3Y-TZP/BNNS interfaces, revealing that BNNS were homogeneously distributed throughout the matrix with an abrupt transition at 3Y-TZP/BNNS interfaces. BNNS effectively hindered slow crack growth, thus increasing the composite's crack growth resistance by about 30 %. A 1 MPa·m^1/2 rising R-curve was also induced by crack bridging.

This scientific review delves into the innovative realm of polyolefins/light alkanes valorization through their catalytic dehydrogenation employing pincer-ligated iridium organometallic complexes. These widely studied catalysts exhibit outstanding properties, although the intrinsic characteristics of homogeneous catalysis (such as challenging product–catalyst separation, poor applicability to continuous-flow processes and low recyclability) limit their activity and industrial application, as well as their thermal stability. Through the immobilization of complexes on inorganic supports, these downsides have been bypassed, harnessing the true potential of these catalysts, affording more selective and stable catalysts in addition to facilitating their implementation in industrial processes. The findings described herein contribute to the advancement in the understanding of catalytic processes in hydrocarbon transformations, offering promising avenues for sustainable and selective production of valuable chemical intermediates from readily available feedstocks.

The ability to control the porosity of thin oxide films is a key factor determining their properties. Despite the abundance of dry processes for synthesizing oxide porous layers, a high porosity range is typically achieved by spin-coating-based wet chemical methods. Besides, special techniques such as supercritical drying are required to replace the pore liquid with air while maintaining the porous network. In this study, we propose a new method for the fabrication of ultraporous titanium dioxide thin films at room or mild temperatures (T <= 120 degrees C) by a sequential process involving plasma deposition and etching. These films are conformal to the substrate topography even for high-aspect-ratio substrates and show percolated porosity values above 85% that are comparable to those of advanced aerogels. The films deposited at room temperature are amorphous. However, they become partly crystalline at slightly higher temperatures, presenting a distribution of anatase clusters embedded in the sponge-like open porous structure. Surprisingly, the porous structure remains after annealing the films at 450 degrees C in air, which increases the fraction of embedded anatase nanocrystals. The films are antireflective, omniphobic, and photoactive, becoming superhydrophilic when subjected to ultraviolet light irradiation. The supported, percolated, and nanoporous structure can be used as an electron-conducting electrode in perovskite solar cells. The properties of the cells depend on the aerogel-like film thickness, which reaches efficiencies close to those of commercial mesoporous anatase electrodes. This generic solvent-free synthesis is scalable and applicable to ultrahigh porous conformal oxides of different compositions, with potential applications in photonics, optoelectronics, energy storage, and controlled wetting.

En este trabajo, la Titania se modificó por sulfatación o fluorización y platino en superficie, con el objetivo de mejorar la eficiencia en la reducción de Cr (VI) en comparación con el material TiO2 base sintetizado por el método sol-gel. Los materiales fueron caracterizados por DRX, SBET, UV-Vis DRS, FRX, TEM, FTIR y XPS. Las modificaciones permitieron obtener una mayor estabilidad en la fase Anatasa y en el área superficial del semiconductor. La adición de F y Pt en el TiO2 provocaron aumentos de absorción en la región visible del espectro electromagnético. Se observó una correlación entre las nuevas propiedades fisicoquímicas obtenidas tras la modificación del TiO2 y el rendimiento fotocatalítico del material. El mejor resultado en la reducción de cromo se obtuvo utilizando Pt-S-TiO2 como fotocatalizador, este material mostró una combinación adecuada de área superficial, alta absorción UV-Vis, alta hidroxilación y la existencia de nanopartículas de Pt en la superficie que favorecen un aumento de la vida media del par electrón-hueco. También se evaluaron parámetros de reacción que demostraron que el mejor desempeño fotocatalítico se obtuvo bajo atmósfera de N2, intensidad de luz de 120 W/m2 y 2 horas de tiempo total de reacción. Así mismo, se observó que aumentar el tiempo de reacción de 2 a 5 horas tuvo un efecto perjudicial sobre la eficiencia en la reducción de Cr (VI).

Laser-induced graphene (LIG) on paper is a popular choice for fabricating flexible micro-supercapacitors (MSCs) as it is a simple and sustainable process. However, carbon-based MSC electrodes have limited energy densities. To address this challenge, this study presents a highly reproducible and cost-effective method for decorating manganese oxide (MnOx) x ) on interdigital LIG MSC electrodes, fabricated via a single-step direct laser writing (DLW) process on paper substrates. The paper fibers embedded with MnOx x precursors are transformed into graphene through laser processing while reducing the salt, resulting in the formation of MnOx-LIG. x-LIG. The resulting MnOx-LIG-MSC x-LIG-MSC exhibits a specific capacitance of 12.30 mF cm- 2 (0.05 mA cm- 2 ) with a 60 % retention at 1000 bending cycles (30 degrees), degrees ), due to the pseudocapacitive contribution of MnOx. x . Furthermore, the devices exhibit high electrochemical stability, retaining 190 % of the initial specific capacitance after 10,000 cycles, and a high energy density of 2.6 mu Wh cm-- 2 (at a power of 0.109 mW cm-- 2 ). The study demonstrates that manganese oxide- based LIG-MSCs have the potential to be used as energy storage devices for portable, low-cost, and flexible paper electronics.

This study focused on the development of vanadium-based catalysts for formic acid production from glucose. The influence of different vanadium precursors on the catalytic activity of titania supported catalysts was contemplated and compared to the performance of commercial and synthesized unsupported V2O5. The obtained results reveal a successful deposition of multiple vanadium species on TiO2 as confirmed by XRD, Raman, and UV-Vis measurements. Catalyst screening identifies V5+ species as main player indicating its important oxidizing potential. Afterwards, the key reaction conditions, as temperature, time, pressure and catalyst loading, were optimized as well as the state of the catalyst after the reaction characterized.

Magnetron sputtering of two materials (Aluminum and Silicon) was performed in He gas and led to the formation of very different porous thin films: a fiberform nanostructure or a gas/solid nanocomposite. The composition of the thin films obtained was analyzed by means of ion beam techniques: Rutherford backscattering and proton elastic backscattering spectroscopies to measure the amount of Al(Si) deposited atoms and that of He atoms inserted inside the films. Microstructural and crystalline properties were analyzed by scanning electron microscopy and X-ray diffraction. Transmission electron microscopy coupled with electron energy loss spectroscopy were used to investigate the presence of empty or He filled pores or even bubbles. Correlating the Al(Si) film properties with the deposition conditions evaluated by SRIM (sputtering process at the target) and by a homemade collision code (species transport to the substrate) gave a better insight into the reason for the formation of such different films. The role of both He ions backscattered at the target and surface mobility during the growth is discussed. Comparison with low kinetic energy He + implantation experiments indicates that similar mechanisms, such as He insertion, diffusion inside the lattice, release or accumulation into pores and bubbles, are certainly taking place.

The Intergovernmental Panel on Climate Change (IPCC) recognises the pivotal role of renewable energies in the future energy system and the achievement of the zero-emission target. The implementation of renewables should provide major opportunities and enable a more secure and decentralised energy supply system. Renewable fuels provide long-term solutions for the transport sector, particularly for applications where fuels with high energy density are required. In addition, it helps reducing the carbon footprint of these sectors in the long-term. Information on biomass characteristics feedstock is essential for scaling-up gasification from the laboratory to industrial-scale. This review deals with the transformation biogenic residues into a valuable bioenergy carrier like biomethanol as the liquid sunshine based on the combination of modified mature technologies such as gasification with other innovative solutions such as membranes and microchannel reactors. Tar abatement is a critical process in product gas upgrading since tars compromise downstream processes and equipment, for this, membrane technology for upgrading syngas quality is discussed in this paper. Microchannel reactor technology with the design of state-of-the-art multifunctional catalysts provides a path to develop decentralised biomethanol synthesis from biogenic residues. Finally, the development of a process chain for the production of (i) methanol as an intermediate energy carrier, (ii) electricity and (iii) heat for decentralised applications based on biomass feedstock flexible gasification, gas upgrading and methanol synthesis is analysed.

The increasing anthropogenic emissions of greenhouse gases (GHG) is encouraging extensive research in CO₂ utilisation. Dry reforming of methane (DRM) depicts a viable strategy to convert both CO₂ and CH₄ into syngas, a worthwhile chemical intermediate. Among the different active phases for DRM, the use of nickel as catalyst is economically favourable, but typically deactivates due to sintering and carbon deposition. The stabilisation of Ni at different loadings in cerium zirconate inorganic complex structures is investigated in this work as strategy to develop robust Ni-based DRM catalysts. XRD and TPR-H₂ analyses confirmed the existence of different phases according to the Ni loading in these materials. Besides, superficial Ni is observed as well as the existence of a CeNiO₃ perovskite structure. The catalytic activity was tested, proving that 10 wt.% Ni loading is the optimum which maximises conversion. This catalyst was also tested in long-term stability experiments at 600 and 800°C in order to study the potential deactivation issues at two different temperatures. At 600°C, carbon formation is the main cause of catalytic deactivation, whereas a robust stability is shown at 800°C, observing no sintering of the active phase evidencing the success of this strategy rendering a new family of economically appealing CO₂ and biogas mixtures upgrading catalysts.

Herein we study the economic performance of hydrochar and synthetic natural gas co-production from olive tree pruning. The process entails a combination of hydrothermal carbonization and methanation. In a previous work, we evidenced that standalone hydrochar production via HTC results unprofitable. Hence, we propose a step forward on the process design by implementing a methanation, adding value to the gas effluent in an attempt to boost the overall process techno-economic aspects. Three different plant capacities were analyzed (312.5, 625 and 1250 kg/hr). The baseline scenarios showed that, under the current circumstances, our circular economy strategy in unprofitable. An analysis of the revenues shows that hydrochar selling price have a high impact on NPV and subsidies for renewable coal production could help to boost the profitability of the process. On the contrary, the analysis for natural gas prices reveals that prices 8 times higher than the current ones in Spain must be achieved to reach profitability. This seems unlikely even under the presence of a strong subsidy scheme. The costs analysis suggests that a remarkable electricity cost reduction or electricity consumption of the HTC stage could be a potential strategy to reach profitability scenarios. Furthermore, significant reduction of green hydrogen production costs is deemed instrumental to improve the economic performance of the process. These results show the formidable techno-economic challenge that our society faces in the path towards circular economy societies.

The rapid growth of global energy consumption and the increasing demand for sustainable and renewable energy sources have urged vast research into harnessing energy from various sources. Among them, the most promising approaches are nanogenerators (NGs) and solar cells (SCs), which independently offer innovative solutions for energy harvesting. This review paper presents a comprehensive analysis of the integration of NGs and SCs, exploring advanced hybrid structures and their diverse applications. First, an overview of the principles and working mechanisms of NGs and SCs is provided for seamless hybrid integrations. Then, various design strategies are discussed, such as piezoelectric and triboelectric NGs with different types of SCs. Finally, a wide range of applications are explored that benefit from the synergistic integration of NGs and SCs, including self-powered electronics, wearable devices, environmental monitoring, and wireless sensor networks. The potential for these hybrid systems is highlighted to address real-world energy needs and contribute to developing sustainable and self-sufficient technologies. In conclusion, this review provides valuable insights into the state-of-the-art developments in NGs and SCs integration, shedding light on advanced hybrid structures and their diverse applications.

Among the challenges that wastewater treatment plants face in the path towards sustainability, reducing CO 2 emissions and decrease the amount of waste highlight. Within these wastes, those that can cause eutrophication, such as nutrients (nitrogen and phosphorous) are of great concern. Herein we study a novel process to concentrate nutrients via membrane technology. In particular, we propose the use of forward osmosis, applying the carbonated solvent which contains the CO 2 captured from the biogas stream as draw solution. This carbonated solvent has a high potential osmotic pressure, which can be used in forward osmosis to concentrate the nutrients stream. To this end, we present the results of an experimental plan specifically designed and performed to evaluate two main parameters: (1) nutrients concentration; and (2) water recovery. The process designed involves pH adjustment, membrane filtration to separate solids, pH reduction and forward osmosis concentration of nutrients. With this process, concentrations factor for nutrients in between 2 and 2.5 and water recovery of approximately 50 % with water flux of 7 to 8 L/(m 2 h) can be achieved.

Extensive research into green technologies is driven by the worldwide push for eco-friendly materials and energy solutions. The focus is on synergies that prioritize sustainability and environmental benefits. This study explores the potential of abundant, non-toxic, and sustainable resources such as paper, lignin-enriched paper, and cork for producing laser-induced graphene (LIG) supercapacitor electrodes with improved capacitance. A single-step methodology using a CO₂ laser system is developed for fabricating these electrodes under ambient conditions, providing an environmentally friendly alternative to conventional carbon sources. The resulting green micro-supercapacitors (MSCs) achieve impressive areal capacitance (≈7–10 mF cm⁻²) and power and energy densities (≈4 μW cm^-2 and ≈0.77 µWh cm⁻² at 0.01 mA cm⁻²). Stability tests conducted over 5000 charge–discharge cycles demonstrate a capacitance retention of ≈80–85%, highlighting the device durability. These LIG-based devices offer versatility, allowing voltage output adjustment through stacked and sandwich MSCs configurations (parallel or series), suitable for various large-scale applications. This study demonstrates that it is possible to create high-quality energy storage devices based on biodegradable materials. This development can lead to progress in renewable energy and off-grid technology, as well as a reduction in electronic waste.

We study the thermal properties of a bulk Ni₅₅Fe₁₉Ga₂₆ Heusler alloy in a conduction calorimeter. At slow heating and cooling rates (∼1Kh^-1), we compare as-cast and annealed samples. We report a smaller thermal hysteresis after the thermal treatment due to the stabilization of the 14 M modulated structure in the martensite phase. In ultraslow experiments (40mKh^-1), we detect and analyze the calorimetric avalanches associated with the direct and reverse martensitic transformation from cubic to 14 M phase. This reveals a distribution of events characterized by a power law with exponential cutoff p(u)∝u^-εexp(-u/ξ) where ε∼2 and damping energies ξ=370μJ (direct) and ξ=27μJ (reverse) that characterize the asymmetry of the transformation.

In this work, we have expanded the possibilities of the multiphase-flash sintering (MPFS) technique by investigating several configurations that involve multiple dogbone specimens (ranging from 1 to 3) and multiple phases (also ranging from 1 to 3). Unlike the traditional MPFS approach using complex 3D or cylindrical samples, this new method allows for a direct comparison with the established conventional flash sintering technique. Our experimental results with dense 8-mol% Yttria-stabilized zirconia demonstrate a significant reduction in the onset temperature as the number of phases and dogbones increases. Building on these findings, we achieved the preparation of pure bulk specimens of SrFe₁₂O₁₉ for the first time through reactive multiphase-flash sintering.

A bifunctional catalyst, comprising GaZr oxide and SAPO-34 zeolite, manifests enhanced catalytic activity in CO₂ hydrogenation to light olefins; nonetheless, the comprehensive analysis of the pivotal role played by the underlying structure of ZrO₂ in Ga-Zr oxide has not been investigated. Herein, different crystalline structures of ZrO₂ were prepared by the co-precipitation method and adopted as a support to deposit Ga to obtain ZrO₂ with different ratios of monoclinic ZrO₂ (m-ZrO₂) to tetragonal ZrO₂ (t-ZrO₂) in GaZr oxides for CO₂ hydrogenation to light olefins. Various characterizations demonstrated that the interface between Ga and the mixed phase of (m-t) ZrO₂ produces more oxygen vacancies which favors the adsorption and activation of CO₂, and the larger specific surface area and stronger H₂ adsorption and dissociation capacity promote CO₂ conversion. Interestingly, the GaZr oxide with high m-ZrO₂ content exhibits superior catalytic activity than the GaZr oxide with high content of t-ZrO₂. The highest light olefins yield (9.0%) and selectivity (77.9%) (CO free) with 27.9% CO₂ conversion was achieved. In-situ DRIFT spectra further elaborated that the GaZr oxides with different ZrO₂ crystalline phases follow the same reaction pathway to hydrogenate CO₂ first to HCOO* and then to CH₃O* on GaZr oxide surface. While compared with sole ZrO₂, the introduction of Ga significantly promotes the hydrogenation of HCOO* to CH₃O*, acting as a crucial reaction intermediate that subsequently diffuses into SAPO-34 pores to enhance the desired light olefins selectivity. 

Hybrid organometal halide perovskites (HP) present exceptional optoelectronic properties, but their poor long-term stability is a major bottleneck for their commercialization. Herein, a solvent-free approach to growing single-crystal organic nanowires (ONW) is presented, along with nanoporous metal oxide scaffolds and HP, to form a core@multishell architecture. The synthesis is carried out under mild vacuum conditions employing thermal evaporation for the metal-free phthalocyanine (H₂Pc) nanowires, which are the core, plasma-enhanced chemical vapor deposition (PECVD) for the TiO₂ shell, and co-evaporation of lead iodide (PbI₂) and methylammonium iodide (CH₃NH₃I/MAI) for the CH₃NH₃PbI₃ (MAPbI₃/MAPI) perovskite shell. A detailed characterization of the nanostructures by electron microscopy, (S)-TEM, and X-ray diffraction, XRD, is presented, revealing a different crystallization of the HP depending on the template: while the growth on H₂Pc nanowires induces the typical MAPI tetragonal structure, a low-dimensional phase (LDP) is observed on the 1D-TiO₂ nanotubes. Such a combination yields an unprecedentedly stable photoluminescence emission over 20 h and over 300 h after encapsulation in polymethyl methacrylate (PMMA) under different atmospheres including N₂, air, and high moisture levels. Moreover, the unique 1D morphology of the system, together with the high refractive index, allows for a strong waveguiding effect along the HP nanowire length.

In this work, we present the preparation of NaTaO₃/WO₃ systems, a broad-bandgap and a narrow-bandgap semiconductor, respectively, for photocatalytic applications. The samples were prepared by two different methods, microwave-assisted and conventional hydrothermal method, with different NaTaO₃/WO₃ molar ratios. All samples were extensively characterized, and the photocatalytic behavior was studied in the degradation reaction of rhodamine B under simulated solar illumination. A significant synergistic effect in the coupling of the two components could be observed, with an important improvement in the rhodamine degradation rate, especially for the microwave-prepared sample with 1:1 (NaTaO₃/WO₃) molar ratio. The enhancement of the activity can be explained by the formation of type II and Z-Scheme heterojunctions. The obtained results are promising for the development of more efficient photocatalyst materials under solar or visible illumination.

In the present work, fluorinated titanium dioxide (TiO2-F) with high exposition of facet {001} was prepared by following a facile and high yield hydrothermal method assisted by microwave. This faceted TiO2 was then modified by Au or Ag deposition at two different metal loadings (0.125 and 0.25 wt%). A wide physicochemical characterisation of the materials was performed. X-ray difractograms showed high {001} facet exposition in all materials. By X-ray fluorescence it was found that the different samples contained about 5% of fluor. All samples presented high surface area and high uniformity and homogeneity of particles, which highlights the good properties that can be achieved by the microwave synthesis method compared to conventional hydrothermal methods. Oxidation state of the noble metals was studied by XPS. On the other side, TiO2-F and the metallised titania powders were immobilised on polystyrene pellets (PS) for evaluating their gas photocatalytic activity in volatile organic compounds (VOCs) decontamination by following the reaction of photoxidation of ethanol in gas phase. It was found that activity was considerably improved by the addition of noble metals, obtaining high conversion and selectivity to CO2. It is remarkable that the selectivity to CO is almost zero. The highest efficiency was found for the faceted TiO2-F sample with the lowest Au loading (0.125 wt%) immobilised on PS where 91% ethanol conversion and 100% CO2 selectivity were achieved. Different reaction variables were also studied.

The review provides an overview of the latest innovations, trends, and challenges in the field of 3D-printed metal and metal-ion batteries. It focuses on the materials used in the printing of batteries, including electrodes, electrolytes, and other electroactive components. Compared to other high-quality reviews on the topic, this review provides a broader selection of materials that are expected to gain attention in the next few years, such as redox-active polymers and metal-organic frameworks. This work gives an overview and insight into the latest trends in printing techniques as well as a statistical review of their uses and strengths. We have also gathered the latest works done for each of the material types, and we have taken the opportunity to put them in context and use them to exemplify in which direction is the field going. The review concludes with a critical view of the challenges ahead and a discussion of the direction that the field is taking as well as the external factors that might help to define its future. 

PEPAdb (Prehistoric Europe's Personal Adornment Database) is a long-term, open-ended project that aims to improve access to archaeological data online. Its website (https://pepadb.us.es) publishes and analyses datasets about prehistoric personal adornment, drawing on the results of various research projects and bibliographic references.

The surface chemistry and inter-connectivity within perovskite nanocrystals play a critical role in determining the electronic interactions. They manifest in the Coulomb screening of electron-hole correlations and the carrier relaxation dynamics, among other many-body processes. Here, we characterize the coupling between the exciton and free carrier states close to the band-edge in a ligand-free formamidinium lead bromide nanocrystal assembly via two-dimensional coherent spectroscopy. The optical signatures observed in this work show: (i) a nonlinear spectral lineshape reminiscent of Fano-like interference that evidences the coupling between discrete electronic states and a continuum, (ii) symmetric excited state absorption cross-peaks that suggest the existence of a coupled exciton-carrier excited state, and (iii) ultrafast carrier thermalization and exciton formation. Our results highlight the presence of coherent coupling between exciton and free carriers, particularly in the sub-100 femtosecond timescales.