Scientific Papers in SCI

X-ray detectors and scintillators play a crucial role in society, with extensive applications in scientific research, security, manufacturing quality control, and medical imaging, including general radiography, computed tomography, and positron emission tomography. With aging populations globally, the demand for medical imaging is steadily growing, necessitating accessible and affordable X-ray technologies that can provide higher image quality with minimal radiation dosage. Existing commercial technologies possess several drawbacks, including slow response times, poor radioluminescence efficiencies, limited tunability range of X-ray energies, and reliance on costly and energy-intensive production processes. Metal-organic frameworks (MOFs) have recently attracted attention as promising materials for a new generation of X-ray detectors and scintillators that can revolutionise low-dose and high-throughput medical and security imaging and enable unique applications. In this work, we discuss the underlying mechanisms and recent progress made in MOF-based X-ray detectors and scintillators, and examine their unique potential to outperform existing technologies.

The conformation of a NiCo catalyst promoted by CePr on FeCrAlloy thermally pretreated micromonoliths was investigated via washcoating using a colloidal suspension of the catalytic precursor (hydrotalcite, HT) without the use of additives. A high affinity was established between the nature of the reconstructed HT and the layer of the formed alumina microstructures obtained after thermal treatment, which exhibited high material adhesion. The effect of the amount of catalyst incorporated into the sinusoidal microchannels of monoliths was also investigated. The catalytic performance was evaluated for the production of H-2 from oxidative steam reforming of ethanol (OSRE) and compared with that of a powder catalyst (slurry) and an uncoated micromonolith. The results indicated notable benefits from the micromonoliths, especially when incorporating low amounts of catalyst with low layer thicknesses-LT (8 gL-1, layer thickness similar to 0.3 mu m), achieved a hydrogen yield of 2.86 mol(H2)mol(EtOH)(-1), comparable to that of the powder catalyst benchmark (2.91 mol(H2)mol(EtOH)(-1)), but with enhanced stability at 65 h and improved heat and mass transport characteristics. Overall, this study opens the way for the promising feasibility of scaling up the OSRE reaction to produce H-2.

Formamidinium lead iodide perovskite compositions have a low open circuit voltage deficit and thus a higher power conversion efficiency (PCE) potential. However, their low bandgap makes it difficult to achieve a semitransparent perovskite solar cell (ST-PSC) with a high average visible transmittance (AVT) and thus, a high light utilization efficiency (LUE). Attaining a high AVT in such low bandgap perovskite-based semitransparent solar cells requires the perovskite layer to be very thin (thickness < approximate to 100 nm) and the rear electrode to be made of a transparent conductive oxide. Moreover, both the front and rear electrodes should exhibit minimal reflectance losses. In this work, meeting these requirements, fully vacuum-deposited, low bandgap (approximate to 1.55 eV, approximate to 100 nm thick) semitransparent perovskite solar cells are fabricated that demonstrate a high LUE value of 4.2 (PCE: 9.26% and AVT: 45.3%). Additionally, a high color rendering index of 82.4 along with a high AVT of approximate to 48.5% is achieved in a ST-PSC via modulation of the device reflectance by tuning both the perovskite layer thickness and the rear electrode stack. The ST-PSCs retained > 90% of their efficiency for >1000 h when thermally stressed at 85 degrees C in N-2 atmosphere.

Perovskite light-emitting diodes (PeLEDs) have emerged as a promising technology for next-generation display and lighting applications, thanks to their remarkable colour purity, tunability, and ease of fabrication. In this work, we explore the incorporation of plasmonic spherical nanoparticles (NPs) directly embedded into the green-emitting CsPbBr3 perovskite layer in a PeLED as a strategy to enhance both its optical and electrical properties. We find that plasmonic effects directly boost spontaneous emission while also influencing charge carrier recombination dynamics. We present a rigorous theoretical electro-optical analysis to systematically investigate the impact of NP metal, size, and concentration on device performance, with particular emphasis on the role of photon recycling (PR). Our results demonstrate that embedding carefully designed silver (Ag) NPs, selected through rigorous theoretical modelling, into PeLEDs leads to enhanced device performance across a wide range of operating currents. Notably, we observe a 4-fold improvement in external quantum efficiency (EQE) at injection currents as low as 0.02 mA cm-2, and a 2-fold enhancement at 0.2 mA cm-2, attributed to increased radiative recombination. Furthermore, results suggest improved efficiency retention at higher injection levels, pointing to reduced current roll-off limitations and extended high-brightness operation. Additionally, PR plays a crucial role in mitigating optical losses and improving outcoupling efficiency, especially in plasmonic-enhanced systems, where scattering effects increase the prevalence of trapping states. These findings open up exciting possibilities for devices requiring energy-efficient, compact, and high-performance light sources, such as portable electronics and low-power displays.

Nanofiber mats were fabricated by combining cellulose, xylan, and organosolv lignin. The biopolymers, and a small amount (15 wt. %) of polyethylene oxide, were dissolved in a mixture of trifluoroacetic acid and trifluoroacetic anhydride, then blended in various ratios (keeping cellulose as the main component and changing the proportions of lignin and hemicellulose) and processed via electrospinning. The resulting nanofiber mats were systematically characterized for their CIELAB color parameters, morphology, chemical composition, mechanical strength, thermal stability, hydrodynamic behavior, antioxidant capacity, and wettability. The incorporation of organosolv lignin significantly altered the color of the nanofiber mats, making them more brownish, with luminosity values from 90 for L-0 to 58 for L-50. It also disrupted the hydrogen bonding network, as evidenced by the chemical shift of the ATR-FTIR spectra. Additionally, organosolv lignin affected key mechanical properties with mechanical values similar to other polymer nanofibers, while thermogravimetric analysis revealed an enhancement of about 10 degrees C in the heat resistant index, thereby broadening the potential applications of the nanofiber mats. Finally, the presence of organosolv lignin improved antioxidant capacity to values of 100 % of RSA, reduced water uptake, and increased water contact angle to values of 110 degrees for L-50.

Ternary AgSbS2 semiconductor was prepared by one-step mechanochemical synthesis using a planetary ball mill from elemental silver, antimony, and sulfur after 30 min of milling. The cubic AgSbS2 with an approximate crystallite size of 56 nm was successfully produced, as confirmed by the Rietveld refinement. The Raman spectrum confirmed the formation of pure AgSbS2. Morphology characterization using SEM demonstrated the homogeneity of the prepared AgSbS2. UV-Vis spectroscopy showed the suitability of the prepared AgSbS2 for photovoltaic applications, as the optical band gap energy value of 1.67 eV and 1.68 eV was determined from absorbance and transmission measurements for AgSbS2 powder and AgSbS2 thin film, respectively. Photoresponse of AgSbS2 was verified by photocurrent spectroscopy as well as I-V measurements. The photoresponsive current showed 2.3 times increase at 1 V for AgSbS2 powder and 1.6 times increase for AgSbS2 thin film under illumination compared to the current in the dark state. To verify the photoelectric properties for photovoltaic application Si/AgSbS2 diodes were prepared by depositing a thin AgSbS2 film from the AgSbS2 powder on n- Si substrate. The I-V characteristics of diodes show a relatively good rectification effect and sensitivity to illumination in spectral range 500-1100 nm.

The demand for sustainable energy technologies is high due to the depletion and risks linked to fossil fuel usage. Diverse energy technologies, such as regenerative fuel cells, zinc-air batteries, and comprehensive water-splitting devices, possess significant potential for the advancement of green energy. MOFs hold a prominent position among the various kinds of materials utilized in renewable energy technologies. MOFs are highly promising catalysts for renewable energy technologies due to their elevated surface area, diverse chemical functionalities, and tunable pore structure. Consequently, it is essential to develop more conductive MOFs that can be directly employed in modern energy applications. This review offers a comprehensive analysis of renewable energy technologies, such as energy conversion (catalysis), electrochemical energy storage (supercapacitors and batteries), and gas storage (CO2 and hydrogen) which play a key role in the transition toward clean and green resources. Additionally, recent developments in the field are discussed, highlighting emerging trends and future opportunities for broadening the applications and overcoming the current limitations of MOFs. This review aims to present the current landscape of MOFs, emphasizing extensive initiatives, functional alterations, and AI & ML forecasts that will persist in advancing the field, providing transformative remedies to worldwide issues, and representing a new era of innovative materials to tackle future scientific and technological challenges in energy and energy-related applications.

This study reports a dual function material (DFM) composed entirely of non-precious metals for methanol production (13.8 mu mol/g material) at ambient pressure from passively captured CO2 from the air. While state of the art carbon capture and utilisation (CCU) processes rely on expensive CO2 capture systems and a high-pressure catalytic reactor for methanol synthesis, this Ni-Ga-Ca DFM can be an enabler for significant energy efficiency gains in methanol synthesis from CO2 through the direct utilisation of dilute emissions and substantially lower operating pressures. Using operando DRIFT spectroscopy coupled with density functional theory, XAFS, XRD, and TEM-HAADF, a combination of Ni-Ga intermetallic species and their oxides are identified as the active sites. During cyclic operation a shift in selectivity towards methane is observed, which is associated with dynamic restructuring of the DFM. Guided by mechanistic and structural understanding, a synthesis strategy is developed to enhance cyclic stability by mitigating dealloying and Ni particle agglomeration. It is indicated that cyclic stability can be achieved by strengthening the Ni-Ga-Ca interaction, however, there remains a gradual shift in selectivity towards methane which highlights the need for further material optimisation.

Oxide-ion conductors based on tetrahedral anion-related oxides have attracted considerable attention due to their high oxygen-ion conductivity and potential applications in clean energy devices, such as solid-state fuel cells. In this study, we report the improvement of oxide-ion conductivity by Sr2+ doping in isolated tetrahedral zircon-type PrVO4. It is found that Pr0.975Sr0.025VO4-delta features the highest oxide-ion conductivity of 2.62 x 10-3 Scm-1 at 800 degrees C under air, with an oxygen transport number of 0.93. The formation and stabilization of oxygen vacancy defects, as well as the oxide-ion migration mechanism in PrVO4, were investigated through combining experimental characterizations and computing simulations. The results indicate that the concentration of oxygen vacancy defects increases with Sr2+ substitution, and the vacancies are accommodated by the formation of corner-sharing V2O7 dimers. Oxygen-ion migration proceeds via a cooperative mechanism involving V2O7-dimer breaking and reforming assisted by synergistic rotation and deformation of neighboring VO4 tetrahedra. The results provide valuable insights for further investigation and optimization of zircon-type oxides as potential oxide-ion conductors for electrochemical devices.

The Fischer-Tropsch process can be considered as an alternative route to convert fossil fuels such as crude oil, coal, and methane for the production of more environmentally friendly liquid fuels and chemicals. As recoverable sources of carbon, Fischer-Tropsch synthesis (FTS) converts a mixture of CO and H2 to a range of hydrocarbons, which is free of sulfur and nitrogen and low in aromatics. The surface-sensitive investigation of the temperature and pressure effects on the FT synthesis performance over mesoporous carbon-supported iron catalysts was examined by in situ X-ray photoelectron spectroscopy analyses. Raman and Mossbauer spectroscopy measurements illustrated the structural properties of mesoporous Fe-based oxides. Under FTS reaction conditions of 20 and 30 atm, and temperatures of 240, 255, and 270 degrees C with a CO-to- H2 ratio of 1, the solids were active with 38-45% of CO conversion and a rate of 1 x 10-5 molCOg-1s-1. The product distribution gave C1-C4, C5-C9, and C10 + products with the structure of the solid marginally affected by the type of product obtained. The in situ surface XPS analyses were conducted at similar to 240-270 degrees C and 10 atm with a CO-to-H2 ratio of 1 for 1 h. The alpha-Fe2O3 phase was reduced to Fe3O4 resulting in well-dispersed magnetite nanoparticles with further reduction to metallic iron on the mesoporous carbon support. Such alpha-Fe phase demonstrated accessibility of the syngas resulting in the activity of the solids. The chemical evolution of the Fe 2p, O 1s, C 1s, and K 2s core levels during the FTS with increasing the temperature up to 255 degrees C suggested that the surface carburization formed chi-Fe5C2 and theta-Fe3C iron carbide phases along with Fe3O4 and, tentatively, the metallic iron phase. The mesoporous carbon-supported iron catalysts having chi-Fe5C2 carbide determined the activity and stability during the FTS synthesis.

In this paper, 8 mol% yttria cubic stabilized zirconia (8YCSZ) composites with reduced graphene oxide (rGO) contents up to 10 vol% were consolidated by spark plasma sintering (SPS) at two different temperatures with the aim of evaluating the relationship of their electrical properties with the graphene content, the rGO crystallinity, and the microstructural features. Successful in situ reduction of GO was accomplished during SPS, and highly densified composites with homogeneous rGO distribution, even at the highest contents, were obtained. The electrical properties were analyzed using impedance spectroscopy. Measurements were taken up to 700 degrees C, revealing an inductive response for the composites with 5 and 10 vol% rGO and a capacitive response for the composites with 1 and 2.5 vol% rGO. The results indicate that, along with the ionic conduction typical of zirconia, there are additional polarization mechanisms associated with the presence of graphene at ceramic grain boundaries that substantially modify the impedance response. A minor electronic conductivity contribution was identified in the composites below the percolation threshold. These characteristics make the 8YCSZ composites promising candidates for application as SOFC components, as ceramic interconnects when the graphene content is above the percolation threshold, or as electrolytes when the graphene content is below this limit.

Fabricating Al2O3-Y3Al5O12-ZrO2 ceramic composites with a eutectic microstructure is challenging and costly, as it requires high-temperature melting of precursor materials. Here, we report on the successful production of Al2O3-Y3Al5O12- 5 mol% ZrO2 composites with lamellar eutectic microstructure through single-step spark plasma sintering (SPS) of sol-gel synthesized powder. The release of volatile species from partially calcined powders, due to limited calcination at 1000 degrees C for 2 h, as well as their fine particle size, were used to create the conditions for local electric discharge and plasma formation during SPS; this resulted in the local formation of eutectic liquids, enabling the formation of lamellar microstructures. The microstructural features can be tailored by modifying the calcination process.

In this study, the potential of a bimetallic Metal-Organic Framework Zn-MIL53(Fe) for electro-Fenton catalysis was evaluated. After the material characterisation, its catalytic activity was validated in Fenton reaction to degrade a model organic pollutant: Rhodamine B. After that, the evaluation of Zn-MIL53(Fe) as electro-Fenton catalyst was performed and improved outcomes were reached by electro-Fenton regarding anodic oxidation. Then, electro-Fenton treatment optimisation was carried out using response surface methodology assays considering different catalyst dosages (7.2-43.2 mg), current intensities (5-45 mA) and treatment time (30-90 min) in a volume of 0.1 L. Under optimal conditions, a degradation rate over 90 % for Fluoxetine and Sulfamethoxazole in synthetic wastewater was achieved within 90 min, using graphite sheet as anode and nickel foam as cathode (25 mA), with a catalyst dosage of 43.2 mg in a volume of 0.1 L. Additionally, its application in the pathogen inactivation was evaluated using different gram-negative and gram-positive bacteria. Complete eliminations of both types of bacteria were reached in 5 min using the optimal conditions. In the end, Zn-MIL53(Fe) was proven as a reusable material, capable of performing 3 complete cycles of electro-Fenton treatment for both types of pollutants bacteria and pharmaceuticals, which makes it a promising candidate for more efficient wastewater treatment applications which involve the Fenton reaction.

The high-temperature stability of solar absorber paints is critical for the efficiency of concentrating solar power systems, particularly central towers operating at similar to 800 degrees C, where ion interdiffusion at the coating/substrate interface is significant. This work examines the effect of a diffusion barrier (DB) formed by controlled surface oxidation of stainless steel 316L (SS316) and Inconel 625 (INC625) at 800 degrees C to improve the thermal stability and optical performance. A CrAlSiN/AlSiO solar absorber tandem structure was deposited on oxidized and unoxidized substrates, with their stability compared after annealing at 800 degrees C for 2 h. The presence of the DB layer resulted in improved thermal stability and optical performance, with post-annealing absorptance values of 0.953 (SS316) and 0.949 (INC625), surpassing those of the reference samples, without the diffusion barrier (0.932 and 0.901, respectively). Microstructural and spectroscopic analyses confirmed the effectiveness of the DB, highlighting its potential for advanced concentrating solar power applications.

This 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 degrees 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 (tau similar to 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.

The valorization of carbon dioxide into high-value-added hydrocarbons, especially light olefins (C2-C4=) through sustainable energy input holds significant industrial value, offering a route for producing essential chemical feedstocks while simultaneously mitigating the emission of this potent greenhouse gas. Despite significant advancements in CO2 hydrogenation technologies, developing efficient catalysts capable of effectively managing C-O bond activation and facilitating C-C bond growth with high conversion rates and desired selectivity for low-carbon olefins, remains a significant challenge. This high-caliber review explores the transformative potential of CO2 valorization into C2-C4=, offering an innovative pathway to produce vital chemical feedstocks while addressing greenhouse gas emissions. Focusing on the CO2-modified Fischer-Tropsch synthesis through iron- catalyst, recognized for its energy efficiency and suitability for C2-C4= production through thermocatalytic CO2 hydrogenation. Key highlights include in-depth analyses of the dynamic nature of catalytically active iron phases, novel materials, and state-of-the-art catalyst design strategies to overcome the challenges of Anderson-Schulz- Flory (ASF) limitations and low olefin selectivity. With a comprehensive discussion on reaction mechanisms, catalyst composition, and performance-driving factors, this review sets the stage for pioneering advancements in catalyst development. Thus, by bridging fundamental insights with cutting-edge technologies, this work provides strategic guidance for developing the next generation of efficient and sustainable catalytic systems for CO2 hydrogenation.

Single-atom catalysts (SACs) have emerged as a promising class of materials, leveraging the benefits of both homogeneous and heterogeneous catalysis to enhance efficiency and selectivity. In this work we have investigated the catalytic performance of SACs supported on graphitic carbon nitride (g-C3N4) for hydroformylation reactions. A systematic evaluation of nine transition metal SACs (Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, and Pt) anchored on g-C3N4 was conducted using a combination of Density Functional Theory (DFT) calculations and experimental validation. Computational results indicate that at higher metal loadings, most metal atoms tend to migrate into the interlayers of g-C3N4, reducing their accessibility to reactant species and limiting their involvement in the catalytic process. However, Ru, Os, Ir, and Co single atoms remain stabilized on the heptazine rings, residing on the outermost layer and preserving active sites, albeit with lower predicted catalytic activity compared to Rh, while Fe, Ni, Pd, and Pt preferentially localize within the interlayers. Ru, Rh, and Co SACs anchored on g-C3N4 were experimentally synthesized and characterized using Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), along with catalytic testing, confirming the single-atom nature of the catalysts and corroborating the theoretical findings.

In this study, we successfully enhanced the electrochemical energy storage properties of commercial carbon felts by modifying their surface with metal-organic frameworks (MOFs) of the zeolitic imidazolate framework (ZIF) type, incorporating Fe, Co, Ni, Cu, and Zn as metal centres. These modifications were achieved through two distinct processes: layer-by-layer deposition and a hydrothermal synthesis method. The resulting materials were thoroughly characterized using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/ EDX), X-ray diffraction (XRD), inductively coupled plasma spectroscopy (ICP), and cyclic voltammetry (CV) in a three-electrode cell. Our findings indicate that the materials synthesized via the hydrothermal process exhibited superior electrochemical performance compared to those obtained through the layer-by-layer method. In light of the findings, the study progressed to the device stage, specifically a single-cell vanadium redox flow battery. In this stage of the study, the modified electrodes were characterized using two key techniques: galvanostatic charge-discharge and electrochemical impedance spectroscopy. This characterization revealed that electrodes modified with ZIF structures displayed significantly reduced polarization compared to those fabricated with the unmodified commercial felt. The ZIFs that exhibited the most significant enhancements in electrocatalytic performance were those based on Zn, Cu, and Ni (in this order), as these metals demonstrated higher deposition levels on the carbon felt electrodes and exhibited superior dispersion. The enhancements resulted in significant performance improvements, with energy efficiency increases of up to 29 % and accessible capacity improvements of up to 33 %. This research demonstrates the potential of ZIF-modified carbon felt as a highly effective electrode material for vanadium redox flow batteries, paving the way for more efficient and scalable energy storage systems. Despite the minimal metal content present in the MOFs, our results demonstrate a significant enhancement in electrode performance, highlighting the efficiency of this approach and its potential to optimize the electrochemical activity of VRFB electrodes with minimal material usage.

Nanocolumnar thin films deposited at oblique angle (OA) by magnetron sputtering or evaporation often show common structural aspects when grown under equivalent geometrical conditions. This is the case of the column tilt angle as a function of the geometrical deposition arrangement, which coincides for some materials no matter the technique. This feature has usually been taken as a sign of a common type of growth, even though no other morphological aspects have been systematically compared. In this paper, a comparison between nanocolumnar Pt thin films grown at OA by evaporation and magnetron sputtering has been carried out, demonstrating the existence of profound differences in film density, columnar width or preferential crystalline texture, despite exhibiting the same nanocolumnar tilt. Moreover, the size distribution of voids and nanopores embedded in the nanocolumns has been specifically analyzed by means of two Positron Annihilation Spectroscopy techniques, demonstrating the existence of large variations depending on the preparation method. With the help of a growth model, these differences are discussed under the light of the atomistic processes present in evaporation and magnetron sputtering and, more specifically, on mobility processes triggered by the arrival of deposition atoms with relatively high kinetic energy.

Electrolysis, the process of splitting water into hydrogen and oxygen using electrical current, stands as a pivotal technology in the current hydrogen economy. Among various electrolyser technologies, proton exchange membrane water electrolysers (PEMWEs) are favored for their high efficiency, durability, and suitability for commercial applications. However, the cost of PEMWE systems, particularly the bipolar plates (BPs), which account for similar to 25 % of system costs, remains a critical challenge. Stainless steel BPs has been explored as a cost-effective alternative to titanium BPs, but they require protective coatings to prevent corrosion under PEMWE conditions. This study focuses on developing titanium suboxide (Ti sub-oxide) coatings for stainless steel BPs to enhance corrosion resistance, maintaining a moderate contact resistance. Ti sub-oxide coatings were deposited using High-Power Impulse Magnetron Sputtering (HiPIMS), a technique enabling high-density and homogeneous material deposition. Key strategies to increase coating compactness, including substrate polarization and cyclic ion bombardment during deposition, were investigated. Morphological and compositional analyses were conducted, along with evaluations of corrosion resistance and electrical performance. The results demonstrate that Ti sub-oxide coatings developed with the selected approaches, exhibit improved compactness, which could potentially limit electrolyte infiltration, enhancing the durability and performance of stainless steel substrates. These findings highlight the promising behavior of Ti sub-oxide coatings under harsh PEMWE conditions. While further studies are needed in actual PEM electrolyzers, they suggest a cost-effective solution for advancing PEMWE technology and green hydrogen scalability toward Net Zero goals.

This study proposes a fast and simple method for the in situ growth of metal-organic frameworks (MOFs) on metal oxide substrates as an alternative to the traditional approaches of using gold substrates and self-assembled monolayers (SAMs). As a case study, zeolitic imidazolate framework 8 (ZIF-8) crystals were grown in micro columnar TiO2 films through simple alternate and successive immersions of the TiO2 films into solutions containing the MOFs precursors. The growth process of the MOF crystals in the interstitial spaces between the TiO2 columns was investigated by varying the metal-to-ligand ratio (1:2, 1:4, and 1:8) and by employing modulating agents such as triethylamine. It was found that the optimal deposition of ZIF-8 occurred when using a higher excess of ligand and the addition of triethylamine after a controlled number of immersion cycles. These results were obtained by using glancing angle X-ray diffraction (GAXRD) and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) as characterization techniques. Additionally, a density functional theory (DFT) study as well as Fourier-transform infrared spectroscopy (FTIR) and GAXRD experiments were conducted to elucidate the nucleation process. It was concluded that the starting point is the formation of a covalent bond between the Zn cations and the TiO2 on the metal oxide surface after immersion of the film into a Zinc (II) nitrate solution, allowing for the formation of MOF nuclei once the film is subsequently immersed in the 2-methylimidazole solution. The results demonstrate the feasibility of in situ growth of MOF crystals onto metal oxide structures by a layer-by-layer strategy, offering a promising alternative to conventional methods.

In recent years, coffee waste by-products have been incorporated into polymer blends to reduce environmental pollution. In this study, coffee parchment (CP) was incorporated into biodegradable polylactic acid (PLA) and poly (butylene adipate-co-terephthalate) (PBAT) polymer blends to prepare ribbons through the extrusion process. Extracted green coffee bean oil (CO) was used as a plasticizer, and CP was used as a filler with and without functionalization. A solution of chitosan nanoparticles (ChNp) as a coating was applied to the ribbons. For the raw material, proximal analysis of the CP showed cellulose and lignin contents of 53.09 +/- 3.42% and 23.60 +/- 1.74%, respectively. The morphology of the blends was observed via scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) showed an increase in the ribbons' thermal stability with the functionalization. The results of differential scanning calorimetry (DSC) revealed better miscibility for the functionalized samples. The mechanical properties showed that with CP incorporation into the blends and with the ChNp coating, the Young's modulus and the tensile strength decreased with no significant changes in the elongation at break. This work highlights the potential of reusing different by-products from the coffee industry, such as coffee oil from green beans and coffee parchment as a filler, and incorporating them into PLA PBAT biodegradable polymer blend ribbons with a nanostructured antimicrobial coating based on chitosan for future applications in food packaging.

To commercialize lead halide perovskites as light-emitting diodes (LEDs), the operational device lifetime needs to be drastically improved. For this to be achieved, an understanding of degradation behavior under bias is crucial. Herein, we perform operando measurements of the structural, chemical, and electronic changes using synchrotron-based grazing-incidence wide-angle X-ray scattering and hard X-ray photoelectron spectroscopy on full-stack deep blue mixed bromide/chloride lead halide perovskite LEDs. While a clear drop in optoelectronic performance is recorded under electrical bias, the accompanying X-ray scattering data reveals only minor changes in structural properties. However, photoelectron spectroscopy reveals substantial chemical changes at the electron-injecting interface after bias is applied, including the formation of unwanted metallic lead and a new chlorine species that is not in the perovskite structure. These operando approaches give important structural and interfacial perspectives to reveal the degradation mechanisms in these LEDs and highlight the need to address the top electron-injecting interface to realize step-changes in operational stability.

Ferulic acid amides are naturally present in the cell walls of potato (Solanum tuberosum) periderms. In this study, we investigated their modes of incorporation into the periderm cell wall polymers. A lignin/suberin-enriched fraction was isolated and analyzed by GPC, DFRC, and 2D-NMR. The analyses revealed that the lignin domain of this fraction was predominantly composed of G-lignin units, with an H:G:S ratio of 2:70:28 (S/G ratio of 0.40). More importantly, the data also indicated the presence of two ferulic acid amides, feruloyltyramine and feruloyloctopamine, that are incorporated into the lignin/suberin structure of potato periderms through a variety of linkages, including 8-O-4' and 4-O-beta' ether linkages, as well as 8-5' linkages forming a phenylcoumaran structure involving the ferulate moiety. Although the phenolic groups of the tyramine and octopamine moieties could theoretically undergo oxidation, potentially creating additional sites for radical coupling, our research indicates that these groups remain predominantly as free phenolic entities that do not participate in radical coupling. On the other hand, all the phenolic groups of the ferulate moieties are bound through ether linkages reinforcing the conclusion that the feruloyltyramine and feruloyloctopamine moieties are linked to lignin/suberin within the cell wall via radical coupling reactions.

Two series of functionalized activated carbons have been prepared and used for the glucose to fructose isomerization reaction. Alkali earth chlorides and alkali halides have been chosen for the functionalization with the final goal to study the effect of cation and anion variation on isomerization activity. A part of the samples has been subjected to an activation procedure giving rise to the formation of new active sites of a distinct type and composition. The active site nature and density greatly influenced the reaction mechanism, giving rise to combined pathways catalyst with increased activity and fructose selectivity. The functionalization with MgCl2 resulted in a very stable and performant catalyst with an optimal fructose yield of 33% at 140 degrees C in only 20 min reaction time and during four cycles of reutilization.

A novel and straightforward one-step method has been developed for the controlled deposition of gold nanoparticles (AuNPs) with uniform diameters onto the titanosilicate (TS-1) zeolitic surface via a direct anionic exchange (DAE) approach. This innovative process simultaneously introduces auxiliary mesoporosity into the zeolite framework, overcoming critical limitations associated with traditional microporous catalysts, including diffusion constraints and rapid deactivation. The resultant hierarchical Au/TS-1 catalyst demonstrates remarkable enhancements in catalytic performance for the liquid-phase propylene epoxidation with H2O2 coupled with outstanding stability, a challenge that has long hindered the application of such materials. With its exceptional catalytic properties and simplified preparation procedure, this system represents a significant advancement in catalyst design. The developed material shows great potential for industrial applications and paves the way for the creation of next-generation catalysts essential for sustainable development.

The utilization of nickel-ruthenium as bimetallic catalysts is widely recognized for its efficacy in enhancing the catalytic performance in the carbon dioxide methanation reaction. The present study focuses on the synergistic interplay between both active sites and their respective roles in the reaction mechanism through operando DRIFT-MS analysis. Findings reveal that the bimetallic catalyst is constituted by NiRu nanocrystallites with Ru atoms segregated at defect edge/corner sites, promoting the dissociation of carbon dioxide and the formation of CH x species. Furthermore, Ni atoms predominantly occupy facets or terrace sites, characterized by higher electron density conducive to carbon monoxide hydrogenation to methane. This research offers a comprehensive elucidation of the carbon dioxide methanation mechanism within a bimetallic system and underscores the efficacy of the operando methodology in advancing our fundamental understanding of heterogeneous catalysis.

This work describes the application of three different AgBr heterojunctions with TiO₂, SnO₂ and WO₃ in the treatment of two water sources: wastewater from a dairy industry facility (WDI) and water from a polluted river (WPR). All heterojunctions were widely characterised, and it was observed that the physicochemical properties of all the coupled materials were similar; however, the highest elimination of Enterobacteriaceae (>90%) was obtained with the AgBr/WO₃(20%) photocatalyst in WDI. Under the same conditions, with this photocatalyst, the complete removal of bacteria (i.e., E. coli, total coliforms and other Enterobacteriaceae) was achieved in WPR. The chlorides, hardness and colour in the two water samples decreased after photocatalytic treatment with all the coupled materials. However, nitrate levels and chemical oxygen demand increased due to the possible formation of intermediary species from the photodegradation of organic pollutants and the release of metabolic intermediates from bacterial degradation during the photocatalytic process. Overall, heterogeneous photocatalysis based on AgBr-coupled materials shows potential as a tertiary treatment for WDI and for the purification of vegetable irrigation water. However, it is still important to consider the need to optimise the integrity of photocatalytic materials in order to maintain their bactericidal effectiveness through continuous reuse.

The search for flexible piezoelectric materials to build adaptable sensors, electronics, and nanogenerators has become a key area of interest. The addition of piezoceramic particles to piezoelectric polymers, such as the copolymer poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE), is one of the strategies used to enhance the piezoelectric response. In this work, the effect of BaTiO3 content on the beta-phase formation, crystallization, and piezoelectric and dielectric properties of the polymer-based composites is investigated. High-energy ball milling was used as an effective, greener technique to achieve well-dispersed mixtures compared to those obtained using organic solvents. During the dispersion process, amorphization and reduction of the crystalline domain size occur. After compression molding and postprocessing, the crystallinity was recovered and was strongly dependent on the filler content. Although significant differences in the beta-phase fraction were not observed, conformational defects are induced with high BaTiO3 contents. The interlayer distances became smaller due to the presence of the ceramic particles after compression molding and remained almost unchanged after postprocessing. For the composites, the minimum voltage required to obtain a measurable piezoelectric coefficient (d 33 ) was significantly reduced compared to neat PVDF-TrFE, even for low contents, which is key for real applications. Three different piezoelectric behaviors were found depending on the BaTiO3 fraction. For composites with 40 vol %, where both matrix and filler contribute to the overall piezoelectric response, the use of a two-step poling method induced a synergistic effect with an increase in d 33 of similar to 180%. However, the relaxation of the ceramic contribution after 24 h returns the value of d 33 to that obtained by applying a one-step poling strategy.