The development of biocompatible and multifunctional inorganic nanomaterials is crucial in nanomedicine, requiring a balance of structural precision, safety, and therapeutic efficacy. In this work, we report the synthesis of nanometric dendritic gallium-containing MFI (d-Ga-MFI) zeolites from zeolite embryos functionalized with an amphiphilic organosilane, engineered as safe and bioactive inorganic interfaces. By systematically optimizing the synthesis, precise control over particle size, morphology, and hierarchical porosity was achieved. The final materials are highly crystalline dendritic zeolites with nanometric particle dimensions (<200 nm), high surface areas and pore volumes, with yields exceeding 90%. Optimization of the xerogel route enabled fine-tuning of gallium content and accessibility, yielding structurally balanced materials (d-Ga-MFI-X2-5) in which gallium is predominantly incorporated in tetrahedral coordination sites with a loading of 4 wt% Ga. In vitro evaluation using RAW 264.7 macrophages demonstrated excellent biocompatibility (cell viabilities above 90% across a wide concentration range), together with a marked attenuation of lipopolysaccharide-induced inflammatory responses, outperforming benchmark mesoporous silica nanoparticles. These results demonstrate that d-Ga-MFI zeolites can uniquely combine structural robustness, interconnected hierarchical porosity, and intrinsic immunomodulatory behavior. Overall, this study establishes d-Ga-MFI zeolites as a safe-by-design inorganic platform with strong potential for advanced biomedical applications.

This work explores low-pressure catalytic hydropyrolysis for upcycling plastics from Waste Electrical and Electronic Equipment (WEEE). Three Pd-based catalysts (using Al2O3, n-ZSM-5, and SiO2 as supports) were investigated. Experiments were performed in a custom-made reactor operating at 550 degrees C / 350 degrees C in the thermal / catalytic zones, respectively, under 50 vol% H2/N2 as the carrier / reactive gas and at 6 bar. The main product was the oil fraction (yields over 65 wt%), having a high concentration of valuable aromatic hydrocarbons, coming mainly from ABS and PS polymers contained in the raw WEEE plastics. Among the three catalysts, Pd/ SiO2 exhibited the best performance, sharply reducing the Cl content in the oil and achieving complete Br removal. A reference test with pure SiO2 indicated that the support alone possesses some halogen trapping capacity, although in quite lower extension than the Pd/SiO2 catalyst. The incorporation of Pd into the silica support enhanced both the oil dehalogenation and the conversion of oligomeric/heavy species, which is reflected in an increase in the GC-MS detected components. Therefore, these results denote that WEEE plastics hydropyrolysis over Pd/SiO2 catalyst is an effective treatment for the upgrading and dehalogenation of the so-produced oil fraction.

Aldol condensation of biomass-derived compounds offers a sustainable route to jet fuel precursors. This study explores catalysts based on nanocrystalline ZSM-5 zeolite (n-ZSM-5) modified with various metals (Ca, Mg, Sn, Ti, Zr) for the aldol condensation of furfural (FFL) and cyclopentanone (CPO). While both reactants can enter the ZSM-5 micropores, the resulting C10 (FC) and C15 (F2C) adducts are too large to be formed within or to exit the microporosity, being instead produced over the external acid sites. Metal modification significantly impacts catalytic activity: Ca and Mg reduce conversion, Sn is neutral, whereas Zr and Ti leads to enhanced performance. The TiO2/n-ZSM-5 catalyst shows by far the best behavior, doubling FFL conversion and sharply increasing the FC + F2C yield, which is attributed to a synergistic effect arising from the generation of accessible weak Lewis acid sites by highly dispersed TiO2 that complement the external Brønsted acidity of ZSM-5.

Electrical and electronic equipment waste (WEEE) is among the fastest-growing waste streams, posing recycling challenges due to its high heterogeneity and the presence of organo-halogenated compounds. Hydropyrolysis offers a promising way to convert WEEE plastics into valuable, dehalogenated organic liquids, facilitating their upcycling. This study examines catalytic hydropyrolysis at mild pressure of real WEEE plastics containing both chlorine and bromine. Nickel-based catalysts on various supports (Al2O3, n-ZSM-5 zeolite, SiO2, and activated carbon (AC)) were tested in batch and continuous systems. In the thermal reaction, over 70 wt% oil was obtained, decreasing slightly with catalyst use. Char played a key role in removing halogens, retaining up to 95%, which was reinforced by the dehalogenation activity of the catalysts. While all catalysts were highly efficient for oil dehalogenation, the best performance was shown by Ni/AC. The AC support alone contributed significantly to halogen trapping, while Ni incorporation into the catalyst further enhanced the oil dehalogenation degree, allowing total Br removal and reducing its Cl content to just 9 ppm, as well as enhancing the production of valuable monoaromatic hydrocarbons. The Ni/AC catalyst exhibited high stability over time on stream when using a continuous oil feeding reaction system and could be fully regenerated by water/dioxane washing, restoring its dehalogenation capability to the level of the fresh one. This work highlights the potential of catalytic hydropyrolysis to address the environmental challenges posed by WEEE plastics, offering a sustainable alternative for their dehalogenation and upcycling into valuable chemical products.

The preparation of hierarchical USY zeolite, exhibiting uniform mesoporosity and high Si/Al atomic ratio (48-52), has been investigated by means of a surfactant/ammonia post-treatment applied to a commercial USY sample. The procedure involved the use of temperatures within 40-135 degrees C, a low ammonia concentration solution (0.05 N) and hydrothermal synthesis times of 20 h. When working at 40-80 degrees C, the obtained USY samples exhibit enhanced intraparticular mesoporosity (324-418 m2 g-1), showing increasingly uniform mesopores around 4.0 nm, while holding a remarkable zeolitic microporosity (413-363 m2 g-1). In contrast, higher temperatures resulted in a steady abatement of crystalline zeolitic domains, with a total collapse of the zeolite structure at 135 degrees C. These hierarchical USY materials were tested in the alkylation of phenol with isopropanol, wherein one of the obtained products, e.g. 2,6-diisopropylphenol (Propofol), is the most important intravenous anaesthetic in the market. Interestingly, the generation of the uniform mesoporosity in USY samples led to an enhancement of both the phenol conversion and the selectivity towards C-alkylation products. Thus, the sample treated at 60 degrees C (USY-60) gave rise to the highest selectivity towards C-alkylation products (84 %) and polyalkylphenols formation (72 %), with an encouraging selectivity towards 2,6-diisopropylphenol (43 %).

This study investigates the influence of lignocellulosic biomass properties on aromatic hydrocarbon (AR) production by catalytic pyrolysis using a ZSM-5 zeolite as catalyst in a fixed-bed reactor. First, using a batch reaction system, vine and olive pruning, oak, and wheat straw were tested as feedstocks. A high lignin content in the biomass increased both char yield and bio-oil oxygen content, although not affecting AR production. In contrast, a high alkali and alkaline metal content reduced the AR yield. Oak was selected for the catalyst-bed temperature optimisation in a continuous reactor, as this biomass led to a low char yield and a bio-oil with a reduced oxygen content and a significant AR share. The highest AR carbon yield (15.1 wt% during the first hour of reaction) was achieved at 450 °C. Higher temperatures (500 °C) promoted severe cracking reactions leading to gases, while lower temperatures (400 °C) provoked a faster catalyst deactivation due to enhanced deposition of carbonaceous matter with a higher concentration of oxygenated oligomeric/heavy species. AR formation from light oxygenates, followed by the oligomerization/cyclization/aromatization pathway, is affected earlier along the time on stream than through Diels-Alder condensation reactions.

A fast and simple post-synthesis method for creating secondary mesoporosity in EMT zeolites was developed using an ammonium fluoride / cetyltrimethylammonium bromide (NH4F/CTAB) solution at low temperature with ultrasound irradiation. This strategy is shown to be highly effective for producing hierarchical EMT structured zeolites through the etching of both Si and Al species. The catalytic performance of these materials were assessed using glycerol dehydration as a reaction test, which is in addition a relevant reaction due to the high amounts of glycerol generated as a by-product of biodiesel production. The resulting hierarchical EMT structured zeolites exhibited improved catalytic activity and high selectivity towards acrolein (around 80%). This innovative approach creates new opportunities for using hierarchical EMT structured zeolites in processes related with biodiesel manufacture.

Synthesised H-ZSM-5 and H-Beta zeolites with hierarchical porosity (h-H-ZSM-5 and h-H-Beta) have been ionexchanged with alkali (Na+ and K+) and alkaline-earth (Mg2+) metals and have been evaluated as catalysts to produce high value-added products through catalytic pyrolysis of lignin. In comparison with the thermal test, hierarchical zeolites in acid form are effective catalysts for lignin pyrolysis, favouring the production of valuable light compounds although reducing bio-oil* yield and increasing gas and coke formation. In this way, h-H-ZSM-5 zeolite promotes the formation of oxygenated aromatics, being guaiacols and syringols the major products. Alkali-exchanged variants of this zeolite enhance demethylation reactions improving the selectivity towards 2methoxy-phenol and syringol, by modifying acid site properties. On the other hand, h-H-Beta zeolite, with larger pore size and stronger acidity, leads to higher concentration of oxygenated aromatics for both parent and ion-exchanged catalysts. Specifically, h-KH-Beta promotes the production of 2-methoxy-phenol and syringol. Besides, h-MgH-Beta stands out for its greater selectivity towards phenol and alkylphenols, such as dimethylphenol. Overall, the combination of accessibility, provided by the hierarchical porosity, with the different nature and strength of the acid sites, induced by the ion-exchange with alkali and alkaline-earth metals, allows tailoring the lignin catalytic pyrolysis process to selectively produce high value-added compounds.

In the critical context of global warming, the diversification of the energy sources is urgently required. Regarding mobility, in addition to vehicles electrification and advanced biofuels, hydrogen holds the potential to address significant emission reduction for internal combustion engines. This approach preserves the advantages of current fossil fuel engines, such as established and proven technology, long lifespan, controlled costs, and an ultra-low carbon footprint. Hydrogen is convenient for heavy-duty and off-road applications for which battery capacity is challenging. Currently, two approaches cohabit in the engineering of hydrogen internal combustion engines: the adaptation of a Diesel-based engine or the design of a brand-new engine dedicated to hydrogen. The presented study focuses on a dedicated combustion chamber for hydrogen combustion for heavy-duty applications with a pent-roof cylinder head and a specific piston shape. The key features of the combustion system have been defined through numerical analysis, focusing on the main challenges of hydrogen combustion engine: fuel/air mixing quality, combustion process, and resistance to abnormal combustions. A heavy-duty single-cylinder engine equipped with this optimized combustion system has been tested on a test bench using hydrogen with realistic conditions for the air loop. The test campaign has been focused on the injection strategy and the identification of the optimal settings. A new methodology for characterization of abnormal combustion has been developed to precisely detect pre-ignition or knock at high load. The main limitations have been identified to operate the engine at full load. Finally, the engine has been tuned in the whole operating range with optimal settings and the performances have been benchmarked by comparing with current engines fueled with Diesel or natural gas. 3D simulation feedback has been done also through the test campaign to assess the validity of the numerical approach used to design this hydrogen combustion system.

Dry reforming of methane (DRM) was studied over 5 wt%Ni/MFI catalysts with different Si/Al atomic ratios (40, 100 and infinity). The 5Ni/ZSM-5(40) catalyst, showing the highest acidity (largest Al content), led to the best Ni dispersion with smaller particles (similar to 6 nm). Additionally, for this material the only reduction peak observed at very high temperature (715 degrees C) through H-2-TPR analysis, together with the binding energy of Ni2+ (856.19 eV) in the XPS spectra, denoted a strong interaction of the NiO nanoparticles with the zeolite. In contrast, the same techniques applied to the other catalysts with lower or no Al content showed larger Ni particles with little interaction with the support. Through temperature-programmed DRM tests, it was found that the onset temperature of CH4 conversion was much lower (327 degrees C) for 5Ni/ZSM-5(40) than for the other catalysts prepared with supports of lower acidity (367-474 degrees C). Isothermal tests over 5Ni/ZSM-5(40) denoted that DRM was the predominant reaction at 500, 550 and 600 degrees C, according to the obtained H-2/CO ratio (similar to 1). However, DRM only prevailed at 600 degrees C with the other two catalysts while other competing reactions (mainly catalytic decomposition of methane) occurred at 500 and 550 degrees C. 5Ni/ZSM-5(40) produced the lowest amount of carbon, especially at 600 degrees C (similar to 2 wt%). Therefore, these results evidence the key beneficial role of acidity of the zeolite in the development of selective and stable DRM catalysts operating at relatively low temperatures.

Valorization of waste polyolefins by a sequential combination of thermal pyrolysis and catalytic hydroconversion over a bifunctional metal/acid catalyst (e.g. zeolite) is an efficient route to produce transportation fuels. However, the zeolite strong acidity typically causes extensive cracking and loss of liquid fuels. In this work, mild dealumination with oxalic acid of a hierarchical Beta zeolite was used to achieve Ni 7%/h-Beta catalysts with Si/ Al ratios within the 25 - 130 range. These catalysts were tested in the hydroconversion of a model mixture of LDPE thermal pyrolysis product (1-dodecene/n-dodecane, 50/50 w/w). The highest share of liquid fuels (similar to 90%) was achieved over 7% Ni/h-Beta (SiAl = 130). Besides, due to its high accessibility and tailored acidity, the product contained a meaningful amount of isoparaffins (12%) and a negligible content of olefins (< 3.5%). Thus, this catalyst holds promise for plastic waste hydroconversion towards transportation fuels.

A variety of oxides (titanium, tin, calcium, magnesium, and gallium) were supported over nano-crystalline ZSM-5 zeolite (n-ZSM-5) by wet impregnation, characterized and evaluated for propane dehydrogenation (PDH) reaction. To enhance the catalytic performance of the oxide-modified n-ZSM-5, Pt nanoparticles were also dispersed over the oxides-supported zeolite catalysts by wet impregnation. Finally, Ga-containing MFI zeolites were used as catalysts in the PDH. Ga was incorporated into the zeolite by two different methods, via hydrothermal synthesis and via wet impregnation. In the PDH reaction, Pt-containing samples exhibited a high initial catalytic activity although they suffered a fast deactivation by coke deposition. On the contrary, Ga-containing MFI catalysts showed a remarkable stability in the PDH reaction. In particular, the catalyst in which Ga was incorporated into the MFI structure by hydrothermal synthesis (Ga-MFI (nSH)) achieved the highest catalytic performance in PDH (9% conversion and 80% propylene selectivity) due to the synergy between the Brønsted and Lewis acid sites (BAS and LAS) and the optimal strength of its LAS sites. These results denote the great potential of Ga-MFI zeolites as catalysts in PDH reactions.

The need to develop green and cost-effective industrial catalytic processes has led to growing interest in preparing more robust, efficient, and selective heterogeneous catalysts at a large scale. In this regard, microwave-assisted synthesis is a fast method for fabricating heterogeneous catalysts (including metal oxides, zeolites, metal-organic frameworks, and supported metal nanoparticles) with enhanced catalytic properties, enabling synthesis scale-up. Herein, the synthesis of nanosized UiO-66-NH2 was optimized via a microwave-assisted hydrothermal method to obtain defective matrices essential for the stabilization of metal nanoparticles, promoting catalytically active sites for hydrogenation reactions (760 kgm(-3)day(-1) space time yield, STY). Then, this protocol was scaled up in a multimodal microwave reactor, reaching 86% yield (ca. 1 g, 1450 kgm(-3)day(-1) STY) in only 30 min. Afterward, Pd nanoparticles were formed in situ decorating the nanoMOF by an effective and fast microwave-assisted hydrothermal method, resulting in the formation of Pd@UiO-66-NH2 composites. Both the localization and oxidation states of Pd nanoparticles (NPs) in the MOF were achieved using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray photoelectron spectroscopy (XPS), respectively. The optimal composite, loaded with 1.7 wt % Pd, exhibited an extraordinary catalytic activity (>95% yield, 100% selectivity) under mild conditions (1 bar H-2, 25 degrees C, 1 h reaction time), not only in the selective hydrogenation of a variety of single alkenes (1-hexene, 1-octene, 1-tridecene, cyclohexene, and tetraphenyl ethylene) but also in the conversion of a complex mixture of alkenes (i.e., 1-hexene, 1-tridecene, and anethole). The results showed a powerful interaction and synergy between the active phase (Pd NPs) and the catalytic porous scaffold (UiO-66-NH2), which are essential for the selectivity and recyclability.

Dimethyl carbonate is an environmentally friendly molecule with increasing applications as reactant, solvent, and fuel additive. Oxidative carbonylation of methanol, with reactants in the gas phase and catalyzed by copper- exchanged Y zeolites, is a promising alternative route for dimethyl carbonate production. This work is focused on the improvement of the catalyst formulation and preparation methods. Catalysts were prepared using two methodologies: solid-state ion exchange and liquid-ethanol ion exchange. Five different copper salts were used as precursors and the NH4+ and Na+ forms of the Y zeolite as supports. The Na+ form of the Y zeolite removed the Bronsted acidity of the support and, therefore, the reaction rate of acid-catalyzed undesired dehydration and decomposition reactions was reduced. The use of copper chloride salts as precursors was crucial to obtain suitable catalysts for dimethyl carbonate formation. Among all the tested catalysts, those prepared using CuCl2 precursor and the Na-Y zeolite by the liquid-ethanol ion exchange method showed the best performance (0.72 molDMC/molCu h). This catalyst exhibited the highest surface chloride content and Lewis acidity.

Pyrolysis affords the conversion of plastics from Waste of Electrical and Electronic Equipment (WEEE) into oils with potential applications in the production of valuable chemicals and the formulation of liquid fuels. However, the presence of significant concentrations of halogens (Cl and Br) in these wastes represents an important limitation as it can lead to the generation of hazardous species that negatively affect the environment. In this work, the catalytic pyrolysis of a real WEEE plastic has been investigated using a reaction system that operates with continuous feeding of the raw material. The catalysts assayed include bulk metal oxides (Fe2O3 and CaO) and zeolites (ZSM-5 and USY), as well as hybrid solids obtained by supporting those metal oxides on the zeolites. Pre-treatment of the raw WEEE plastics by water washing allows the Cl concentration to be significantly reduced, but it does not affect the Br content. Thermal pyrolysis produces an oil fraction with a high yield (> 70 wt.%) and a large concentration of halogens (700 ppm), even though the char produced effectively retains more than 90% of Br and Cl contained in the feedstock. During catalytic pyrolysis, the halogen content of the oil is further reduced obtaining the best dehalogenation results with the metal-modified zeolites. This fact evidences a synergetic effect derived from the high metal dispersion achieved over the zeolitic supports. Fe/ZSM-5 is the most promising catalyst, showing an almost constant dehalogenation activity along the time-on-stream and producing an oil enriched in monoaromatic hydrocarbons (mainly styrene).

The adsorptive dechlorination of a pyrolysis oil coming from real plastic waste was investigated using different Na-zeolites (4A, 13X, and Y) as adsorbents. The dechlorination experiments were performed in a fixed bed trap under inert atmosphere operating at moderate temperatures (< 180 °C). The dechlorination efficiency of the adsorbents was significantly improved by performing a dehydration pre-treatment due to the removal of water molecules physisorbed on the zeolite surface. Among the zeolitic materials tested, 13X zeolite showed the best dechlorination efficiency, which was related to its high content of Lewis acid sites (attributed to the presence of Na+ cations ionically interacting with the zeolite framework), acting as chemisorption sites, as well as the high accessibility of the FAU-zeolitic topology to the Cl-containing compounds. For that sample, a detailed study of the adsorption temperature (from 30 to 180 °C) and time on stream (1-6h) was further carried out. The maximum chlorine removal efficiency was achieved, reducing the chlorine content of the pyrolysis oil from 421 to 45 ppm, at temperatures of about 150 – 180 °C. Interestingly, under these conditions, thermal or catalytic cracking effects of the zeolite on the feedstock were not observed. However, the study of the time on stream showed that, after 3h, the chlorine removal efficiency of the zeolite started to decrease. Thus, different regeneration treatments were evaluated proving that, after a combustion at 600 °C, the zeolite recovered its initial dechlorination efficiency. This research reveals the potential of the adsorptive dechlorination process with Na-zeolites to reduce the chlorine content in plastic pyrolysis oils under mild operating conditions.

A new era of possibilities for dendritic zeolite The ERC Advanced Grant TODENZE project aims to develop a new type of highly accessible zeolites exhibiting a dendritic nanoarchitecture, which could provide remarkable benefits in a wide range of fields. In particular, the project explores the use of dendritic zeolites as catalysts for biomass valorisation and as nanocarriers for combined drug and gene therapies.

This study explores the isomerization of limonene-1,2-epoxide (LE) from kinetic and mechanistic viewpoints, using a dendritic ZSM-5 zeolite (d-ZSM-5) as a highly selective catalyst for the formation of dihydrocarvone (DHC) in the form of diastereoisomers (cis + trans). Ethyl acetate, a green solvent, was used at mild reaction temperatures (50---70 degrees C). DHC, which can also be extracted from caraway oil, is widely used as an intermediate for epoxylactone production and as a constituent in flavors and perfumes. Kinetic modeling of LE isomerization was performed using a reaction network with eight parallel reactions and the corresponding rate equations, derived from the assumption of the rate-limiting surface reactions. The large standard errors in the statistical results of some kinetic parameters of the initial data fitting suggested that three of those reactions can be neglected to describe the kinetic model more accurately. This refinement resulted in standard errors in the kinetic parameters lower than ca. 11 %, confirming the statistical reliability of the modified kinetic model. Activation energies of 41.1 and 162 kJ/mol were estimated for the formation of cis-DHC and trans-DHC, respectively. Density Functional Theory (DFT) calculations revealed the preferred pathway for both cis and trans-LE conversion to DHC and carveol. The rate-determining step, carbocation formation (Delta Eact = 234 kJ/mol), precedes near-instantaneous dihydrocarvone formation under the studied conditions.