The transition from petrochemical-based resources to renewable biomass is a key objective in sustainable chemical production. Biomass-derived polyols are promising feedstocks for the production of light olefins, which are essential intermediates in the polymer and fuel industries. However, their selective deoxygenation remains challenging due to the hydrophilicity of polyols, the reliance of deoxydehydration (DODH) reactions on expensive rhenium-based catalysts, and the harsh reaction conditions typically required. Herein, a series of rhenium-based heterogeneous catalysts was prepared by supporting ReOx species on either single oxides (SiO2, Nb2O5, CeO2, ZrO2) or mixed metal oxides (SiO2-Nb2O5, CeO2-ZrO2) prepared via soft-template (ST) method. Extensive catalytic screening using diethyl tartrate as a model substrate revealed a strong dependence of the activity on the nature of the support. Among the investigated systems, the ReOx/SiO2-Nb2O5 catalyst emerged as the most active and robust system, delivering high yields under significantly milder conditions (130–170 °C), compared to typical DODH protocols. A combined experimental and computational analysis demonstrated that catalytic activity is governed by the interplay between support properties and the oxidation states distribution of surface rhenium species. In particular, a high fraction of reduced Re species in combination with high surface area correlate with enhanced activity, thus being identified as key requirements for optimal performance. The SiO2-Nb2O5 support enables efficient stabilization of active species and mitigates rhenium leaching, resulting in excellent recyclability over multiple catalytic cycles. These findings underscore the critical role of support composition and synthesis methodology in tuning catalytic performance. Overall, this work delivers a practical and scalable DODH protocol, offering a valuable step forward in the catalytic conversion of renewable feedstocks into high-value chemicals within a circular economy framework.

A synthesis strategy combining an impregnation approach with a self-combustion process to develop Ni-based catalysts (5–15 wt% of Ni) supported on mesoporous CeO2 is proposed. This strategy favors an intimate Ni–CeO2 coupling enabling a fine NiO dispersion in form of ultrasmall particles/clusters on CeO2. Comprehensive characterization, including XRD, Raman, N2-physisorption, HRTEM, STEM-EDXS/EELS, H2-TPR, CO2-TPD, and H2-TPD, revealed a strong metal–support interaction and promotion of oxygen vacancy formation. CO2 methanation testing under atmospheric pressure demonstrated high CO2 conversion and near-complete CH4 selectivity. At lower reaction temperatures, CO₂ conversion increased with Ni loading, which can be reasonably attributed to the higher concentration of oxygen vacancies. However, above 325 °C, the catalyst with the lowest Ni content exhibited performances comparable to the other samples, likely due to its very high Ni dispersion. Notably, a critical comparison with state-of-the-art systems, despite differences in operating conditions, highlighted the outstanding performance of the catalysts, particularly in terms of methane productivity (256-486 ), CO2 conversion (68-85 mol%) and CH4 selectivity (close to 100%) under mild conditions. The results place the obtained Ni–CeO2 catalysts among the most effective systems reported to date for CO2 methanation with strong potential for integration in sustainable catalytic technologies.

Developing metal-organic frameworks (MOFs) that combine high CO2 uptake, ultramicroporosity, and stability under humid conditions remains a challenge for practical carbon capture. Here, a rational and optimized synthetic strategy allows to eliminate Co(OH)2 impurities, unlocking previously inaccessible ultramicroporosity in a robust cobalt-based MOF, constructed from Co(II) nodes and the multitopic 3,6 N-ditriazolyl-2,5-dihydroxy-1,4-benzoquinone (trz2An) linker. This protocol increases the accessible surface area of 50% while preserving a narrow pore size distribution centered at 3.6 Å, critical for CO2:N2 selectivity. Static CO2 adsorption measurements reveal uptake values of 5 and 4 mmol g-1 at 0 and 30 °C, respectively. Dynamic breakthrough experiments with 5-10% CO2:N2 mixtures demonstrate excellent separation performance and stability over 15 cycles, with mild regeneration in N2 at room temperature. Notably, the optimized material exhibits a 24% and 46% increase in CO2 uptake at 10 and 25 °C, respectively, compared to the nonoptimized analogue. In addition, and notably in contrast to most CO2 adsorbents, CO2 uptake further increases under humid conditions, reaching a 65% enhancement, highlighting a beneficial role of water in the adsorption process. This increase is reasonably attributed to transient pore opening due to guest-induced linker flexibility, allowing ultramicropore accessibility without compromising structural integrity. These findings demonstrate how targeted synthetic control can activate latent porosity in rigid ultramicroporous MOFs, offering a viable pathway toward CO2 capture under realistic operating conditions.

Highly efficient (MFe)zeolite catalysts were employed to degrade and mineralize the non-steroidal anti-inflammatory drug nimesulide (NIM) via a Fenton-type reaction. NIM was successfully extracted from generic tablets with an 80% yield, and its purity was confirmed through FTIR, H-1 NMR, and UV-Vis spectroscopy. The (MFe)zeolite catalysts-where M represents Co, Ni, Cu, or Zn-were prepared via ion exchange starting from NaY zeolite and thoroughly characterized by different techniques. In the absence of metal species, both NIM and total organic carbon (TOC) removals were low (<17%). Conversely, a significant enhancement was observed with the (CoFe)NaY catalyst, which achieved 47% NIM degradation and 25% TOC removal at natural pH and 25 degrees C. The optimal reaction conditions obtained by the central composite design (CCD), pH 3.0, 48 degrees C, 100 mg/L H2O2, 0.5 g/L (CoFe)NaY catalyst, and 180 min of reaction time, allowed achieving complete NIM removal (100%) and TOC reduction (88%). The catalyst demonstrated high stability, maintaining activity over five consecutive reuse cycles in a batch reactor and for similar to 200 h of time-on-stream in a continuous flow reactor. The oxidation mechanism was confirmed to be hydroxyl radical-based, as demonstrated by the inhibition in the presence of dimethyl sulfoxide (DMSO) as scavenger. Temperature influenced the nature of intermediate by-products: at the optimal temperature (48 degrees C), only oxalic acid was detected, while at 25 degrees C, both oxalic and oxamic acids were quantified. In the experiment conducted under optimal operating conditions, in addition to oxalic acid, other intermediate compounds were identified, however their concentrations were negligible.

Solutions containing equal concentrations of each metal ion pair (Zn/Fe, Co/Fe, Ni/Fe) were simultaneously added to the zeolite NaY using the ion-exchange method. The resulting bimetallic-zeolites were used as heterogeneous catalysts for the Fenton-like reaction for azorubine dye degradation. The optimization of the reaction parameters was assessed using the Box-Behnken design by studying the influence of H2O2 concentration, catalyst mass, and temperature. For each catalyst, the reaction kinetic was well fitted to the pseudo-first-order model. The best result was obtained with the (ZnFe) NaY catalyst obtaining 98 % of degradation within 60 min, with a rate constant of 0.0424 min-1, followed by (CoFe)NaY and (NiFe)NaY, which achieved 89 % and 81 % of removal after 90 min, with rate constants of 0.0246 min-1 and 0.0162 min-1, respectively. Finally, the highest efficiency of (ZnFe)NaY opens up its applicability for large-scale wastewater treatment, using low-cost materials which further underscores its commercial potential.

The heat of water adsorption on large-pores mesoporous silica suitable for hemostatic applications has been assessed. The values were determined by means of microcalorimetry (as differential heat of adsorption, Q diff, at 318 K) and variable temperature IR (VTIR) spectroscopy through the thermodynamic analysis of spectroscopic data based on the van't Hoff equation (as standard enthalpy of adsorption, Delta H 0, in the temperature range 318-360 K). The results obtained by the two different techniques are in satisfactory agreement, leading to a value of the water heat of adsorption between 30 and 37 kJ/mol, ascribed to the interaction of water molecules with terminal silanols via one H-bond. The heat of water adsorption (below 44 kJ/mol) reveals that the surface of the large-pores mesoporous silica herein investigated may be considered mainly hydrophobic. For the first time, VTIR spectroscopy of water adsorption has been applied for the characterization of the surface hydrophilicity/hydrophobicity of a silica material.

Hemorrhages are still considered a common cause of death and despite the availability of different hemostatic agents it is still necessary to develop more effective hemostats for bleeding managements in emergency situations. Herein, large-pores mesoporous silica microspheres (MSM) were synthesized, and their surface was modified to enrich the hydroxyls population with the aim of achieving a material with enhanced water adsorption capacity and high hemostatic ability. The success of surface modification was investigated by Fourier Transform Infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA), which confirmed the increase in the amount of surface hydroxyl groups. A hemolysis assay as well as a clotting test were carried out to evaluate the hemocompatibility and hemostatic ability, respectively. It was found that the modified material presented the lowest hemolytic ratio and the lowest clotting time. The novelty of the paper is mainly due to the coupling of the hemostatic ability test with the adsorption microcalorimetry of water. In fact, being the water adsorption on the material surface a crucial factor in the hemostatic activity, microcalorimetry was used for the first time to study the adsorption of water and estimate its heat of adsorption. The data obtained showed that the modified MSM presents a surface able to adsorb a higher amount of water, compared to the pristine MSM, with a low molar heat of adsorption (about 35 kJ/mol), which renders the modified MSM presented in the present study an excellent candidate for producing novel hemostats.

Two hierarchical Y and ZSM5 zeolites were prepared with a surfactant-mediated desilication method. Both the conventional and hierarchical forms were used to prepare NiCu-zeolites via the ion-exchange method. All samples were characterised using different techniques. For the hierarchical materials, N2 physisorption and TEM analyses confirmed the appearance of mesoporosity. Transition metal-containing zeolites were used as novel electrocatalysts for the glycerol electrochemical oxidation reaction (GEOR) in the form of modified electrodes. Cyclic voltammetry was used to investigate the surface properties of the modified electrodes and their activity toward GEOR at different pH provided by different supporting electrolyte solutions, indicating alkaline conditions as the most promising ones. The hierarchical forms showed a remarkable higher activity compared to the conventional ones, together with appreciable yields towards partially oxidized products of industrial interest. Noteworthy, a stable current higher than 10 mA was generated, which is interesting to produce H2 by coupling GEOR and hydrogen evolution reaction.

Solution combustion (SC) remains among the most promising synthetic strategies for the production of crystalline nanopowders from an aqueous medium, due to its easiness, time and cost-effectiveness, scalability and eco-friendliness. In this work, this method was selected to obtain anisometric ceria-based nanoparticles applied as catalysts for the direct synthesis of dimethyl carbonate. The catalytic performances were studied for the ceria and Fe-doped ceria from SC (CeO2-SC, Ce0.9Fe0.1O2-SC) in comparison with the ceria nanorods (CeO2-HT, Ce0.9Fe0.1O2-HT) obtained by hydrothermal (HT) method, one of the most studied systems in the literature. Indeed, the ceria nanoparticles obtained by SC were found to be highly crystalline, platelet-shaped, arranged in a mosaic-like assembly and with smaller crystallite size (≈6 nm vs. ≈17 nm) and higher surface area (80 m2 g-1 vs. 26 m2 g-1) for the undoped sample with respect to the Fe-doped counterpart. Although all samples exhibit an anisometric morphology that should favor the exposition of specific crystalline planes, HT-samples showed better performances due to higher oxygen vacancies concentration and lower amount of strong basic and acid sites.

Diffusional limitations associated with zeolite microporous systems can be overcome by developing hierarchical zeolites, i.e., materials with a micro- and mesoporous framework. In this work, Y and ZSM-5 zeolites were modified using a surfactant-mediated hydrothermal alkaline method, with NaOH and cetyltrimethylammonium bromide (CTAB). For Y zeolite, after a mild acidic pretreatment, the effect of the NaOH+CTAB treatment time was investigated. For ZSM-5 zeolite, different concentrations of the base and acid solutions were tested in the two-step pretreatment preceding the hydrothermal treatment. The properties of the materials were studied with different physical–chemical techniques. Hierarchical Y zeolites were characterized by 3.3–5 nm pores formed during the alkaline treatment through the structure reconstruction around the surfactant aggregates. The effectiveness of the NaOH+CTAB treatment was highly dependent on the duration. For intermediate treatment times (6–12 h), both smaller and larger mesopores were also obtained. Hierarchical ZSM-5 zeolites showed a disordered mesoporosity, mainly resulting from the pretreatment rather than from the subsequent hydrothermal treatment. High mesoporosity was obtained when the concentration of the pretreating base solution was sufficiently high and that of the acid one was not excessive. Hierarchical materials can be obtained for both zeolite structures, but the pretreatment and treatment conditions must be tailored to the starting zeolite and the desired type of mesoporosity.

Acid mine drainage (AMD) is one of the main environmental problems associated with mining activity, whether the mine is operational or abandoned. In this work, several precipitates from this mine drainage generated by the oxidation of sulfide minerals, when exposed to weathering, were used as adsorbents. Such AMD precipitates from abandoned Portuguese mines (AGO, AGO-1, CF, and V9) were compared with two raw materials from Morocco (ClayMA and pyrophyllite) in terms of their efficiency in wastewater treatment. Different analytical techniques, such as XRD diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), N2 adsorption isotherms, and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) were used to characterize these natural materials. The adsorption properties were studied by optimizing different experimental factors, such as type of adsorbent, adsorbent mass, and dye concentration by the Box–Behnken Design model, using methylene blue (MB) and crystal violet (CV) compounds as organic pollutants. The obtained kinetic data were examined using the pseudo-first and pseudo-second order equations, and the equilibrium adsorption data were studied using the Freundlich and Langmuir models. The adsorption behavior of the different adsorbents was perfectly fitted by the pseudo-second order kinetic model and the Langmuir isotherm. The most efficient adsorbent for both dyes was AGO-1 due to the presence of the cellulose molecules, with qm equal to 40.5 and 16.0 mg/g for CV and MB, respectively. This study confirms the possibility of employing AMD precipitates to adsorb organic pollutants in water, providing valuable information for developing future affordable solutions to reduce the wastes associated with mining activity.

We present a series of Ni, Fe, and mixed NiFe-based catalysts, deposited onto ceria prepared with either soft templated (with CTAB) or hard templated (with SBA-15) syntheses. The prepared materials were thoroughly characterized with SEM, HRTEM, EDX, ICP-MS, PXRD, and N-2 adsorption techniques, to fully comprehend their physicochemical properties. All catalysts were then tested for carbon monoxide oxidation reaction at different temperatures, aiming to reach temperature and feed composition conditions typical of combustion exhausts from industrial and power plants (350-400 degrees C, in the presence of competitive species such as CO2 and H2O in the feed). Advanced reaction tests highlighted outstanding materials (especially NiFe catalyst deposited onto hard-templated ceria), displaying catalytic performances able to compete with those typical of noble metal-based catalysts. Such catalysts were further investigated by means of Raman, NEXAFS, H-2-TPR, and CO@FT-IR, unraveling their surface and reduction properties, which make them excellent candidates for replacing more costly noble metal-based catalysts currently employed for CO oxidation reaction.

A series of multicomponent oxide catalysts (CuO/ZnO/MemOn/ZrO2/SiO2, with Me = Mg, Ce, or La) was synthesized through a one-pot soft-template approach and used for CO2 hydrogenation to methanol. In the case of the La-containing catalysts, additional samples were prepared with CuO contents in the range 40–60 wt mg_CH_3OH h^ - 1 g_cat^ - 1 ) being obtained on the CuO/ZnO/La2O3/ZrO2/SiO2 catalyst containing 50 wt

Various heterogeneous catalysts based on rare earth elements (REE) and iron supported on zeolites were selected and analyzed using machine learning approaches. REE were used in the preparation of multiple REE/Fe-zeolite catalysts with lanthanum, praseodymium or cerium obtained by ion exchange or impregnation methods, using FAU or MFI structures as supports. The efficiency of these REE/Fe-zeolite catalysts was examined in Fenton-like reaction, in the degradation of tartrazine (Tar) and indigo carmine (IC) as selected organic pollutants in the aqueous solution. The REE/Fe-zeolite catalysts demonstrated outstanding performance, with Tar being degraded by over 80% and IC 95%. Machine learning algorithms were employed for clustering and classification of the different catalysts, based on their performance. Unsupervised learning algorithms like Principal Component Analysis and K-Means were used for pattern recognition while supervised classifiers were employed to classify the heterogeneous catalysts, considering their ability to degrade dyes by Fenton reaction.

To minimize greenhouse gas emissions, efficient carbon dioxide capture and utilization need to be addressed. In this study, to determine the structure-activity interplay, three different promising catalytic systems for the CO2 hydrogenation process were synthesized using mesoporous silica SBA-15 as a support material: copper-based catalyst with zinc, indium-based catalyst with palladium and iron-based catalyst with potassium. The role of metal-metal oxide interaction has been showed. The use of Cu/Zn catalytic system and SBA-15 allowed to obtain very small crystallite size of tenorite and zinc oxide, good dispersion of active phases with strong basic sites. In order to find the most effective catalyst providing the maximal methanol yield and selectivity, these catalytic systems were compared under the same reaction conditions (250 degrees C, 20 bar, H2 to CO2 molar ratio 4 to 1) using fixed-bed tubular micro-activity reactor. Results showed that the highest methanol yield can be obtained with Cu/Zn/SBA-15 catalyst as might be expected according to obtained characterization.

In this work, we propose two bifunctional nanocomposite catalysts based on acidic mesostructured γ-Al2O3 and a Cu/ZnO/ZrO2 redox phase. γ-Al2O3 was synthesized by an Evaporation-Induced Self-Assembly (EISA) method using two different templating agents (block copolymers Pluronic P123 and F127) and subsequently functionalized with the redox phase using an impregnation method modified with a self-combustion reaction. These nanocomposite catalysts and their corresponding mesostructured supports were characterized in terms of structural, textural, and morphological features as well as their acidic properties. The bifunctional catalysts were tested for the CO2-to-DME process, and their performances were compared with a physical mixture consisting of the most promising support as a dehydration catalyst together with the most common Cu-based commercial redox catalyst (CZA). The results highlight that the most appropriate Pluronic for the synthesis of γ-Al2O3 is P123; the use of this templating agent allows us to obtain a mesostructure with a smaller pore size and a higher number of acid sites. Furthermore, the corresponding composite catalyst shows a better dispersion of the redox phase and, consequently, a higher CO2 conversion. However, the incorporation of the redox phase into the porous structure of the acidic support (chemical mixing), favoring an intimate contact between the two phases, has detrimental effects on the dehydration performances due to the coverage of the acid sites with the redox nanophase. On the other hand, the strategy involving the physical mixing of the two phases, distinctly preserving the two catalytic functions, assures better performances.

The catalytic performance in the direct CO2 methanation of a model biogas is investigated on NiO-CeO2 nanostructured mixed oxides synthesized by the soft-template procedure with different Ni/Ce molar ratios. The samples are thoroughly characterized by means of ICP-AES, XRD, TEM and HR-TEM, N2 physisorption at -196 & DEG;C, and H2-TPR. They result to be constituted of CeO2 rounded nanocrystals and of polycrystalline needle-like NiO particles. After a H2-treatment at 400 & DEG;C for 1 h, the surface basic properties and the metal surface area are also assessed using CO2 adsorption microcalorimetry and H2-pulse chemisorption measurements, respectively. At increasing Ni content the Ni0 surface area increases, while the opposite occurs for the number of basic sites. Using a CO2/CH4/H2 feed, at 11,000 cm3 h-1 gcat-1, CO2 conversions in the 83-89 mol% range and methane selectivities >99.5 mol% are reached at 275 & DEG;C and atmospheric pressure, highlighting the very good performances of the investigated catalysts.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Three raw clays from Morocco were used as heterogeneous catalysts for Fenton-like oxidation of organic pollutants in water. The selected pollutants were two dyes used in the textile industry, Congo Red (CR) and Tartrazine (Tar, known also as a food coloring compound, E102) and Caffeine (Caf), a stimulant drug present in popular beverages such as coffee and tea, commonly used in Morocco. Two different processes were used for their degradation: (i) Fenton-like reaction; and (ii) electro-Fenton-like reaction. Process (i) was used for Tar and Caf degradation in the presence of clays from different region of Morocco (Middle Atlas - ClayMA, Fez - ClayF, and Ourika - ClayO), the best results being obtained with ClayO and ClayMA, on which 60.0% and 23.4% of conversion and 41.0% and 20.5% of mineralization were achieved for Tar and Caf, respectively. Process (ii) was used for degrading CR by clay-modified electrodes (CME) using the rawclays from Fez and Ourika regions (ClayF and ClayO). The stability of the CME was assessed by cyclic voltammetry studies, which proved that they are stable in the experimental conditions used. The electrodegradation of CR dye, performed without hydrogen peroxide in the reaction medium, achieve 67.0% of mineralization at the end of electrolysis (2 h).

The effect of different parameters such as temperature, type of catalyst and hydrogen peroxide (H2O2) con-centration on the degradation of pollutants in water by Fenton-like oxidation was studied by using the Box-Behnken design (BBD), an effective statistical model to design the experiments. Concerning the heterogeneous catalysts, three bimetallic catalysts with lanthanum (La) and iron (Fe) ion-exchanged into zeolites (NaY and ZSM5) and a natural clay from Morocco were prepared and used for Fenton-like oxidation of organic pollutants in water. Tartrazine (Tar, a food coloring compound known as E102) and caffeine (Caf, a stimulant drug present in popular beverages such as coffee and tea) were selected as pollutants due to their presence in several com-mercial products for daily consumption. The BBD model indicated that the optimum catalytic conditions for Fenton-like reaction with an initial pollutant concentration of 30 ppm at pH 3.0 were T = 40 degrees C and 90 mM of H2O2. The maximum conversion values achieved with the best catalyst, LaFeZSM5, were 96.6% for Tar after 180 min and 51.0% for Caf after 300 min of reaction. To increase the conversion of Caf, a modified zeolite electrode was used for electro Fenton-like oxidation without H2O2, at room temperature.