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In this study the photo-response behaviour of Au/TiO2 systems in the preferential CO oxidation in a H2-rich stream (CO-PROX) was investigated by the first time under simulated solar light irradiation at room temperature and atmospheric pressure. Au nanoparticles, with an average size of 2–5 nm, were precipitated-deposited on a mesoporous TiO2, previously synthesized by sol-gel type procedure and thermally treated at different temperatures to obtain anatase/rutile mixed phases. Structural, chemical and optical properties were studied by means of AAS, N2 physisorption, XRD, HR-TEM, DRUV–vis and XPS, investigating the effects of TiO2 polymorphs (anatase, rutile and combination thereof). All samples, containing a very low amount of noble metal (0.5 wt%), resulted very active in the photocatalytic CO-PROX at ambient conditions, attaining very high CO conversion and CO2 selectivity values. The Au/TiO2 sample containing both anatase/rutile polymorphs in the support displayed the highest activity, both in dark and under simulated solar light, due to the simultaneous presence of these two titania crystalline phases, capable to lower the effective band gap of the composite system (2.90 eV) and improving the photocatalytic activity in the studied reaction. This kind of materials may provide a sustainable and feasible approach to selectively oxidize CO in H2-rich stream under solar light irradiation and ambient conditions.

The traditional SBA-15 was modified using pore 1,3,5-trimethylbenzene as pore expander to be evaluated in the adsorption of biomolecules bovine serum albumin (BSA) and cellulase (CEL). In order to study the influence of the acidity in the biomolecules adsorption, porous silicas with molar ratio in a range between 5 and 15 were synthesized. The obtained materials were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption at -196 °C, NH3 thermoprogrammed desorption, infrared spectroscopy and X-ray photoelectron spectroscopy. Then, their adsorption capacity for BSA and CEL was evaluated in batch experiments at 25 °C. The obtained data revealed that BSA adsorption is well-fitted to the Toth model in all adsorbents, while CEL adsorption is well-adjusted to the Henry model. In both cases, the adsorbent with a molar ratio Si/Zr = 15 and pore expander reached the highest adsorption values and showed high desorption capacity.

Pt-containing titanate nanotubes (PTNT) catalyst had PtOx and chlorined-Pt species dispersed on the alkali trititanate nanotube phase (TNT). This solid was morphologically and structurally stable during glycerol acetalization of glycerol with acetone. In contrast, a significant transformation of Ni2+ and Co3+/Co2+ surface species dispersed on TNT provoked morphological, textural and surface changes affecting the catalytic performance of these samples, as observed with the help of HRTEM, XPS, Raman and textural properties measurements. Leaching of Co and Ni species was identified as the main mechanism for the deactivation respectively on Co-containing titanate nanotubes (CTNT) and Ni-containing titanate nanotube (NTNT) catalysts. On the contrary, PTNT performed very well giving rise to 28% of conversion and 11% selectivity to solketal over three reaction cycles of 24 h. This was thanked to the suitable tuning of pore-structure and proper surface acidity of PTNT, resulting in a stable solid for the reaction.

[EN] Solid acid catalysts based on WO3¿SiO2 and WO3¿ZrO2¿SiO2 were prepared by one-pot non-hydrolytic sol¿gel method and tested in the gas phase glycerol dehydration to acrolein. Their structural and textural characteristics were determined by X-ray diffraction (XRD), N2 adsorption, X-ray energy dispersive spectroscopy (XEDS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Their acid characteristics were studied by both temperature programmed desorption of ammonia (NH3-TPD) and FTIR of adsorbed pyridine. Under our operating conditions, all the catalysts were active and selective in the transformation of glycerol to acrolein, which was always the main reaction product. The high selectivity to acrolein is achieved on catalysts presenting a higher proportion of Brønsted acid sites. In addition, the role of oxygen in the feed on catalytic performance of these catalysts is also discussed., The authors would like to acknowledge the DGICYT (CTQ2015-68951-C3-1-R, CTQ2015-68951-C3-3-R and SEV-2016-0683) and Secretary of State for International Cooperation in Spain (Project AP/040992/11) and Ministry of Higher Education and Scientific Research of Algeria for the National Exceptional Program for the fellowships. D. D. thanks MINECO and Severo Ochoa Excellence Program for his fellowship (SVP-2014-068669). Authors also would like to thank the Electron Microscopy Service of Universitat Politecnica de Valencia for their support.

A pore-expanded mesoporous silica (SBA-15) was investigated for the immobilization of a recombinant Candida antarctica lipase B (LIPB). The influence of contact time and medium pH during adsorption, as well as thermal and solvent stability of the immobilized enzyme were evaluated. The best prepared biocatalyst was then evaluated in a model esterification reaction, the production of two flavour esters (e.g. methyl and ethyl butyrate) and in a model hydrolysis reaction, the ethyl hexanoate hydrolysis. The biocatalyst maintained high activity and operational stability even after five successive cycles of synthesis. A commercial C. antarctica lipase B was also immobilized on SBA-15 and evaluated under the same conditions, achieving similar volumetric productivities. In addition, the biocatalyst SBA-15-LIPB was tested in ethyl hexanoate hydrolysis. The influence of reactional medium pH was conducted (pH 5, 7 and 9.2) and the highest biocatalyst activity was at pH 5 (about 636.3 U/genzyme). SBA-15-LIPB and SBA-15-LIPB-GA (crosslinked biocatalyst) were reused for 5 cycles, retaining, after the third cycle, 56.6 and 76.80%, respectively, of its initial activity. The prepared biocatalysts were able to catalyze the model reactions (esterification and hydrolysis) with high activity and reasonable stability.

Mixed Ti Si O materials prepared by non-hydrolytic xerogel method have been employed as diluters for nickel oxide and used in the catalytic oxidative dehydrogenation of ethane. These catalysts have been characterized by several physicochemical techniques such as N2 adsorption, XRD, TPR, TEM, HR-TEM, and XPS. Supported nickel oxide catalysts have been reported to be efficient but only if the nature and the amount of support are controlled. In the present article it is shown that highly loaded (80 wt% NiO) nickel catalysts are more efficient when diluted on mixed Ti Si O materials with appropriate Ti/Si ratios than on pure TiO2 and SiO2 diluters. The catalytic results have been explained on the basis of both the crystallite size and the reducibility of NiO crystallites, as a consequence of the interaction between nickel oxide particles and metal oxides diluters. The optimal Ti/Si ratio in the diluter ensures a good dispersion of NiO because Ti4+ sites and/or very small TiO2 crystallites are highly dispersed in the surface of the matrix allowing a close contact with NiO particles. Small NiO crystallites in contact with titania are highly selective to ethylene in the oxidative dehydrogenation of ethane.

The activity of heterogeneous photo-Fenton catalysts based on iron and supported on commercial alumina was studied for the degradation of rhodamine B, methyl orange and methylene blue under UV irradiation. The catalysts were prepared by impregnation, drying, and calcination or omitting this last step and referred to as dried or calcined samples. All samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption, diffuse reflectance UV–vis absorption spectroscopy and X-ray photoelectron spectroscopy (XPS). The XRD results revealed that all catalysts showed peaks of α-Al2O3 and FeSO4. The band gap of the catalysts compared with alumina decreased, due to the presences of Fe species which functioned as traps inhibiting the electron-hole recombination. The XPS results revealed the presence hydroxyl groups on the surface and the presence of both Fe3+ and Fe2+ in both catalysts. The photodegradation experiments showed that the heterogeneous photo-Fenton process was much faster compared with the heterogenous photocatalyst on all the tested dyes. The dried Fe/Al2O3 with the presence of H2O2 under UV irradiation showed the best degradation of rhodamine B, methyl orange, and methylene blue at 99.6, 100, and 99.1% at 5, 10, and 5 min, respectively. This could probably be ascribed to a good dispersion of Fe particle species on Al2O3, a low band gap and a proper concentration of hydroxyl groups and sulfate groups on the surface. The scavenger test revealed that the hydroxyl radicals played the main role in the photodegradation of dyes in this process compared with the superoxide radicals and positive holes.

Carbon nitride based materials doped with boron were used as support to deposit platinum. The systems were tested in the photo-production of hydrogen using methanol as a sacrificial molecule. Tests under UV and sunlight-type illumination conditions showed an important promoting effect of boron, irrespective of the illumination nature. The measurement of the quantum efficiency was used to assess quantitatively the performance of the catalysts. The outstanding properties of the solids, particularly using sunlight as an energy source of the reaction, were interpreted on the basis of the multitechnique spectroscopic/kinetic study. The results showed that boron affects a significant number of physico-chemical properties. The approach here developed quantitatively assesses the catalytic influence of all such phenomena and shows a complex trade-off between the adsorption of reactants and kinetic steps related to charge carrier attack to methanol.

Gum Acacia (GA) was evaluated for steel inhibition in acidic medium. Weight loss, EIS, and by polarization potentiodynamic curves were used to test it. GA showed a high efficiency in protecting steel from acid, and found as dependent on its concentration (1.0 g/L). AFM allowed comparing the morphology of steel with GA, which was complemented with XPS spectroscopy, which confirmed the complete adsorption of GA by evaluating the surface film composition. Polarization resistance increases when GA concentration does, based on EIS characterization, indicating the formation of a protective layer whereas PDP results showed that, GA behaves as a mixed-type inhibitor.

[EN] NiO and metal-promoted NiO catalysts (M-NiO, with a M/(M+Ni) atomic ratio of 0.08, with M = Nb, Sn, or La) have been prepared, tested in the oxidative dehydrogenation (ODH) of ethane, and characterized by means of XRD, TPR, HRTEM, Raman, XPS, and in situ XAS (using H-2/He, air or C2H6/He mixtures). The selectivity to ethylene during the ODH of ethane decreases according to the following trend: Nb NiO Sn NiO > La NiO > NiO, whereas the catalyst reducibility (determined by both TPR and XAS using H-2/He mixtures) shows the opposite trend. However, different reducibility and catalytic behavior in the absence of oxygen (ethane/He mixtures) have been observed, especially when comparing Nb- and Sn-promoted NiO samples. These differences can be ascribed mainly to a different phase distribution of the promoter. The results presented here are discussed in terms of the nature of active and selective sites for ODH of ethane in selective and unselective catalysts, but also the role of promoters and the importance of their phase distribution., The authors would like to acknowledge the DGICYT in Spain CTQ2012-37925-C03-2, CTQ2015-68951-C3-1-R, and CTQ2015-68951-C3-3-R. Authors thank European Synchrotron Radiation Facility, ESRF (Project CH-4512; BM25-SpLine Beamlime). Authors from ITQ also thank Project SEV-2016-0683 for financial support. D.D. thanks MINECO and Severo Ochoa Excellence Program for his fellowship (SVP-2014-068669). B.S. also thanks UV-INV-AE16-484416. Finally, the authors thank the Electron Microscopy Service of Universitat Politecnica de Valencia for their support.

In this study the removal of benzothiophene (BT) from a synthetic solution with n-octane was evaluated using batch adsorption on modified mesoporous silicas impregnated with iron and cobalt species. The silica was modified to limit the aggregation and enlargement of mesochannels and produce a less ordered structure if compared to SBA-15. The synthesized adsorbents were characterized by X-ray diffraction (XRD), N2 adsorption/desorption isotherms at −196 °C, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Adsorption equilibrium was investigated using different sulphur concentrations (3–15 mmol/L) and temperatures (30–50 °C). Under optimized conditions, the SBA-15 sample modified with NH4F containing 10 g/g of Co showed the highest adsorption capacity (0.101 mmol/g), at 30 °C. Thus it may be inferred that these materials are promising for removal of sulphur in low concentrations from liquid fuels. This article is protected by copyright. All rights reserved

Three cationic exchange resins (PD206, CT269DR and CT275DR), supplied by Purolite ® , with different physicochemical properties have been evaluated in the esterification reaction of the free fatty acid from the castor oil with 2-ethylhexanol in order to obtain products with interesting properties to be used as biolubricant basestock. These resins have been characterized by SEM, elemental analysis (CNHS), TG/DTA and XPS. Likewise, these catalysts have been analyzed after the catalytic reaction to evaluate changes in the active phase during the esterification reaction. The catalytic data reveal that the macroreticular-type resins (CT269DR and CT275DR) show higher conversion values, about 95% after 4 h, than a gel-type resin (PD206) due to several factors, such as the higher amount of available acid sites or the denser divinylbenze matrix, which provides higher thermal and mechanical resistance and minimizes sulfur leaching. The deactivation of the active phase has been ascribed to the strong adsorption of reagents and products on the sulfonic groups located at the surface, as indicated in the XPS spectra of the spent catalysts. The products characterization showed that 2-ethylhexyl ricinoleate exhibited excellent properties at low temperature (pour point −39 °C), viscosity index value compatible with commercial synthetic basestock oils, higher biodegradability than mineral oil and better oxidation stability than the original feedstock.

Molybdenum was incorporated into catalysts based on noble metals (Pt or Pd) and supported on silica in order to evaluate how its presence can modify the catalytic response of monometallic catalysts for hydrodeoxygenation (HDO). To this end, the catalysts were evaluated in the hydrodeoxygenation (HDO) reaction of dibenzofuran (DBF) and characterized by different experimental techniques to understand its structure, texture and acidic properties. Catalytic results showed that the active phase had much influence on the activity and selectivity to different reaction products, although, in all cases, bicyclohexane (BCH) was the main reaction product observed. Molybdenum played a very important role in the case of bimetallic catalysts, mainly in the case of palladium. Molybdenum species improved the selectivity to O-free products related to its capacity to break the C O bond. However, molybdenum activity was nil in the absence of noble metal. Moreover, regardless of the noble metal employed, the reducibility, acidity and dispersion of the molybdenum species changed and this is possibly associated to a synergism effect between noble metal and Mo.

Porous clay heterostructures (PCH) have been synthesized from raw bentonite, obtaining porous materials with high surface area and micro-, meso- and macroporosity. Both raw bentonite and PCH have been evaluated in CO2 adsorption processes at 1 bar and 25 °C. In both cases, adsorption isotherms were well fitted using the Langmuir model, obtaining an increase of the CO2 adsorption from 0.112 mmol CO2 g−1 for the raw bentonite to 0.640 mmol CO2 g−1 in the PCH. In order to improve the CO2 adsorption capacity, raw bentonite and PCH were functionalized with amine species, via grafting using 3-aminopropyltriethoxysilane (APTES) and via impregnation with polyethylenimine (PEI) or tetraethylenepentamine (TEPA). The isotherms of the amine-functionalized samples were adjusted to the Dual-Langmuir model, which assumes the coexistence of physical and chemical adsorption sites. From the profiles of the CO2 isotherms, it can been observed that grafted-PCH with APTES shows the coexistence of physical and chemical interactions, reaching 1.023 mmol CO2 g−1. The adsorption of CO2 on PCH impregnated with TEPA and mainly with PEI is governed by chemical interactions between the amine species located in the porous structure and/or on the surface of the adsorbent and the CO2 molecules, attaining maximum values of 1.644 and 1.465 mmol CO2 g−1 for TEPA and PEI, respectively.

Silica-supported catalysts based on mono and bimetallic nickel and iron phosphides with different Ni:Fe molar ratios (1:0, 3:1, 2:1 and 0:1) were synthesised and tested in the hydrodeoxygenation (HDO) reaction of phenol, a model molecule present in bio-oil derived from pyrolysis of biomass. Tests were performed in a fixed bed reactor under hydrogen pressure (1.5 and 3 MPa) for different contact times. Freshly reduced catalysts were characterised by physisorption of N 2 at −196 °C, CO chemisorption, X-ray diffraction, transmission electronic microscopy, temperature-programmed desorption of ammonia and hydrogen, and X-ray photoelectron spectroscopy. Characterization results revealed that the presence of Ni increased their ability to activate hydrogen and the number of active sites, while the presence of Fe favored the spillover process. By increasing the amount of Ni, the surface became enriched with P, and this was associated with the presence of surface P-OH groups that provided Bronsted acid sites to activate O-containing compounds as well as surface hydrogen species that minimised deactivation by coke deposition. Ni-containing phases presented higher HDO capabilities than FeP ones, but generated some O-containing intermediates. In contrast, the FeP catalyst transformed all phenol molecules into O-free compounds (cyclohexane and mainly cyclohexene).

In this study, the influence of the pore size in mesoporous silica (SBA-15) and the loading of niobium oxide species (Nb 2 O 5 ) have been evaluated on the esterification reaction of free fatty acids from castor oil to obtain products that can be used as bio-based lubricant feedstocks. Characterization techniques such as XRD, N 2 sorption, Raman spectroscopy, NH 3 -TPD, XPS and TEM have been employed to characterize the synthesized catalysts, demonstrating the high dispersion of the niobia species. The catalytic results showed that the SBA-15 support with an average pore size of 8.5 nm and a loading of 12 wt.% of Nb 2 O 5 was the best catalyst to obtain higher conversion values in the esterification reaction of ricinoleic acid. This fact was probably due to the pore diameter of this catalyst was the most suitable for the diffusion of reagents and products. The textural properties were more relevant than the acidic properties for Nb 2 O 5 supported on silica catalysts. The reuse data indicated that the conversion values decrease after each cycle probably due to the formation of carbonaceous deposits in the active sites, discarding the niobium leaching which is negligible. The catalytic activity could be almost thoroughly recovered by using a thermal regeneration treatment.

Sepiolite was treated in HNO 3 solutions with the assistance of microwave radiation. This treatment caused the progressive depletion of Mg 2+ , the gradual degradation of the sepiolite structure and the formation of an amorphous silica phase, which contributes to a noticeable increase of the surface area. The use of microwaves during acid treatment, after few minutes, led to materials with similar S BET to those obtained after 48 h with conventional heating methods. The influence of mineralogical impurities, crystallinity and chemical composition in the reactivity of sepiolite to this treatment was also studied. The obtained materials were impregnated with polyethylenimine and assessed for CO 2 capture and CO 2 /N 2 selectivity at different temperatures. Experimental equilibrium data were fitted to Langmuir and Sips models. The adsorption data revealed that sepiolite can be an interesting adsorbent for CO 2 capture, achieving a capacity of 1.70 mmol g −1 at 338 K and 1 bar, providing a high CO 2 /N 2 selectivity (440 mol CO 2 /mol N 2 ).

Four different preparation routes were applied to obtain Fe-containing carbon catalysts for Fischer Tropsch Synthesis (FTS) including copolymer assisted co-precipitation of iron precursor, chemical modification of ferrocene, sol-gel and wetness impregnation of iron on polymeric carbon. The effects of the FTS reaction temperature and pressure were also examined. Using ferrocene as a starting precursor and applying sol-gel method to prepare the solid, the syngas is readily converted to C10+ hydrocarbons with a conversion of up to 56% and a productivity of 34 mg hydrocarbon.gcat−1.h−1 at 240 °C and 20 atm. Impregnation method gave a Fe/C based catalyst with the highest exposure of active sites, including surface Fe3+ and Fe2+ redox sites with great properties in FTS. Chemical modification of ferrocene route enables the formation of hematite and maghemite nanoparticles on carbon, which were in situ reduced to magnetite and iron carbides, being the latter mostly active for the water gas shift reaction. It is found that copolymer assisted co-precipitation of ferrocene facilitates the production of large crystals of magnetite, which suffered from sintering and coking exhibiting low performance in FTS. Among these methods, sol-gel based catalyst proved to have superior performance due to the good dispersion of Fe, stable magnetite and iron carbide and Fe-doped nitrogen carbon phases production. Based on spent catalysts characterizations, the synergetic effect between magnetite and the iron carbides phases in the sol-gel based catalyst plays an important role in heavy hydrocarbon formation.

Cobalt phosphide catalysts supporting on SiO2 presenting different CoxPy stoichiometry were proved in hydrodeoxygenation (HDO) of two different model molecules present in biomass derived bio-oil such as phenol (Ph) and dibenzofuran (DBF). To investigate composition effects a series of cobalt phosphide catalysts presenting different initial P/Co atomic ratio were prepared. The catalysts were characterized by a range of techniques (N2 physisorption, XRD, TEM, NH3-TPD and XPS) and tested for DBF and Ph HDO activity and selectivity. Characterization results evidenced good textural properties, high dispersion of the active phase, as well as the presence of acid sites after P and Co incorporation. The highest activity was observed for catalysts containing an intermediate P/Co content were the CoP phase was the predominat one. Those catalyst containing Co2P or CoP2 phases were less active in these reactions.

A study was conducted to investigate the effect of the preparation route of ZrO2 in CuO–CeO2/ZrO2 catalysts for the oxidation of carbon monoxide at low temperature (COX). Four ZrO2 supports were synthetized via either type sol-gel methodology or precipitation. The final Cu-Ce-Zr oxide catalysts were prepared by incipient wetness co-impregnation with copper and cerium solutions (with a loading of 6 wt% of CuO and 20 wt% of CeO2). The catalyst crystalline phases, texture and active species reducibility were determined by XRD, N2 physisorption at −196 °C and H2-TPR, respectively; meanwhile the surface composition and copper-cerium electronic states were studied by XPS. The catalytic activity was evaluated in the oxidation of CO to CO2, in the 40–215 °C temperature range. Catalytic results evidenced that the samples prepared by a sol-gel methodology showed, after the impregnation, a severe decrease of specific surface area and pore volume attributable to a wide degree of pore blockage caused by the presence of metal oxide particles and a collapse of the structure partially burying the active sites. A simple co-impregnation of a zirconia support, obtained through facile and fast precipitation, provided instead a catalyst with very good redox properties and high dispersion of the active phases, which completely oxidizes CO in the range 115–215 °C with T50 of 65 °C. This higher observed activity was ascribed to the formation of a larger fraction of highly dispersed and easily reducible Cu species and ceria nanocrystallites, mainly present as Ce(IV), with an average size of 5 nm.

The porous Fe-based catalysts supported on polystyrene mesoporous carbon were studied in the Fischer-Tropsch Synthesis. The solids were pretreated at different calcination temperatures and their characterizations were examined by X-ray diffraction (XRD), Raman spectroscopy, Scanning and Transmission electron microcopies (SEM and TEM), textural properties, elemental composition by X-ray dispersive spectroscopy (EDS), temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). It was shown that the preexistent carbides phases, obtained upon using elevated temperatures of calcinations procedure, were not completely reoxidized during the reaction, while the formation of carbides through the polymeric carbon reaction with magnetite and/or metallic iron resulted in highly active catalyst for FTS.

We present an effective chemical synthesis of bimetallic Nickel-Molybdenum catalysts. The catalysts were made using a sol-gel method with alumina modified by zirconia (Al2O3-xZrO2) support with x = 0, 10 and 15 wt-% respectively. In order to measure their catalytic activity, they were evaluated through hydrodesulfurization (HDS) reaction using industrial gas oil 2 wt-% sulfur content. Results, indicate an important increase of their catalytic activity in presence of zirconia, probably as caused by electron donation from atoms as presented in zirconia tetragonal structure (XRD). Furthermore, using high resolution characterization techniques such as X-ray Photoelectron Spectroscopy (XPS) and Temperature Programmed Reduction of Sulfides (TPR-S) has revealed a special interaction between zirconia and active sites, confirming the electron donation, mainly at Mo octahedral sites, as occurred due to formation of so-called NiMoS phase. In order to complete our analysis, images of High-Resolution Transmission Electron Microscopy (HRTEM) shown dispersed laminar molybdenum sulfide structures with some bending, high stacking over c-axis when the sol-gel alumina was modified by zirconium domains.

A new silicon carbide ceramic membrane consisting of a unique top layer on a SiC support for application in oily wastewaters filtration was produced and characterized in terms of morphology and chemical surface composition by scanning electron microscopy and X-ray photoelectron spectroscopy measurements. The manufacturing process of this new membrane allows time and economic savings when compared with a two layers membrane previously obtained. The new membrane has a smooth top layer with controlled porosity and a higher permeability compared to already developed commercial membranes. Moreover, it is extremely efficient to remove total suspended solids as well as oil and grease and, consequently, it can be applied to effective treatment of industrial oily wastewaters.

A series of samples where platinum is deposited onto titania P25 using a chemical deposition method was tested in the photo-production of hydrogen using methanol as a sacrificial agent. The optimization of the platinum titania contact was analyzed as a function of the synthesis conditions. The catalysts’ structural and electronic properties were measured using a combination of porosimetry, X-ray diffraction, X-ray photoelectron, photoluminescence, and UV–visible spectroscopies, together with a microscopy study of the noble metal particle size distribution and an in situ infrared study of the catalysts under reaction conditions. The measurement of the optical properties of the catalyst suspensions and the subsequent calculation of the true quantum efficiency were used to show that a significant enhancement of ca. 250% can be achieved through the series of Pt-containing catalysts. The study provides solid evidence concerning the physical roots of the photoactivity behavior. For catalysts having equal Pt properties in terms of primary particle size and electron handling capability, a synergy between the noble metal and the oxide support at interface sites is shown to promote the conversion of carboxylate-type surface species into carbon dioxide and maximize the hydrogen yield of the reaction.

In this work, solid wastes from the flocculation step of a drinking water treatment plant were used as starting material to obtain CO2 adsorbents upon thermal treatment and a pillaring strategy. Thermally treated solid waste and pillared materials were characterized by XRD, FTIR, TGA, N2 adsorption–desorption isotherms at 77 K, XPS and elemental analysis. From the characterization results, it was found that the introduction of silica pillars was successful, leading to heterostructured materials with higher specific surface area and pore volume. In order to improve the CO2 adsorption capacity, pillared materials were functionalized by grafting with (3-aminopropyl)triethoxysilane (APTES)and impregnation with polyethylenimine (PEI). Pillared materials could be loaded with up to 50 wt% PEI. PEI-impregnated pillared adsorbents were tested for CO2 adsorption at 298 and 348 K and CO2/N2 adsorption at 348 K using a Magnetic Suspension Balance equipped with a mixture gas dosing (Rubotherm, Germany). Langmuir and Sips models were used to fit monocomponent and mixture experimental data, considering two different sites for CO2 adsorption. At 1 bar, 50PEI-SiFe (loaded with 50 wt% PEI) adsorbed 2.5 and 3.6 mmol CO2 g−1 at 298 and 348 K, respectively and exhibited an extremely high CO2/N2 selectivity (above 150 mol CO2/mol N2 at 348 K). Nevertheless, PEI loaded adsorbents still exhibit a lower amine efficiency as compared to APTES-grafted counterparts, due to diffusion restrictions caused by the high viscosity of the impregnated polymer.

A carbon quantum dots (CQDs) based ratiometric nanosensor exhibiting dual emission fluorescence was developed. The spherical fluorescent carbon nanoparticles were obtained from lactose using a hydrothermal method. Under a single excitation at 355 nm they showed the typical blue emission at 417 nm and a red emission at 550 nm attributed to the coating effect of vitamin B12. The latter is explained by the fluorescence resonance energy transfer (FRET) and it consists of 61% of total emission. Upon the presence of carbofuran phenol 3-Keto, a phenolic metabolite of carbofuran, the red emission was quenched, resulting in a ratiometric fluorescence response in the blue range. This ratiometric nanosensor exhibited a good selectivity to carbofuran phenol 3-Keto. The ratio of I417/I550 linearly decreased with an increasing carbofuran phenol 3-Keto concentration in the range 9.8 μM–1.40 × 10−4 M. A detection limit for carbofuran phenol 3-Keto pesticide was 12.2 μM. The pesticide tested was extracted from soy sauce. Recovery values ranged from 98% to 114% with RSD values from 1.50% to 6.50%.

Chitosan is a biopolymer with potential applications in various fields. Recently, it has been used for heavy metals removal like copper, due to the presence of amino and hydroxyl groups in its structure. Chitosan membranes were crosslinked with epichlorohydrin and bisoxirano and functionalized with chelating agents, such as iminodiacetic acid, aspartic acid and tris-(2-amino-ethyl) polyamine. These membranes were used for copper adsorption and the formed complexes were characterized. Thermal and crystalline properties of chitosan membranes were studied by TG-DCS and X-ray diffraction. Raman, XPS and FT-IR data confirmed that copper is linked to the modified chitosan membranes by the amino groups. The oxidation state of copper-chitosan membranes were also studied by angle resolved XPS, and by UV–Vis diffuse reflectance spectroscopy.

Two series of materials based on graphitic carbon nitride (GCN) and sulfur-containing carbon (physical mixture and composite) were synthesized. The stability of their surface features upon exposure to either water, CO2 or to water and CO2 combined conditions in solar light was tested. Both materials generated photocurrent upon light exposure. The estimated band gap alignments indicate that although on both composite and physical mixture water splitting and CO2 reduction can take place in visible light, differences are expected in their extents. The results suggest that oxidation of water is more favorable on the composite while the physical mixture favors water and CO2 reduction, owing to the preserved s-triazine structure. While the surface of the former is oxidized by released oxygen, on the physical mixture material some degree of self-reduction is also noticed. The decrease in the porosity of the composite is linked to the oxidation of the carbon matrix.

Graphitic carbon nitride and S-doped carbon catalysts were exposed to CO2 and/or water either in the dark or under visible light irradiation. The surface chemistry of the initial and exposed samples was studied by XPS and potentiometric titration. In the case of porous carbon catalysts the changes in porosity were also estimated based on the adsorption of nitrogen. The results showed that exposure to water and CO2 caused changes in its surface chemistry. The changes were especially pronounced when the surfaces were exposed to CO2 under visible light irradiation. Mainly, oxidation of surface carbon atoms was observed, which was accompanied by the reduction of surface nitrogen in the case of g-C3N4, and removal of some sulfur species in the case of S-doped carbons. These changes were the consequence of photosensitivity and the oxidation of water and reduction of CO2. Moreover, the chemical reactivity of water and CO2 was also noticed in the dark, which was linked to hydrolysis and redox reactions, respectively. The changes in the chemistry were apparently affected by the extent of photoactivity and surface reactions, the amount of generated oxygen and the reactivity of the surface atoms. The results showed small but consistent changes in the chemistry and texture of catalysts, which might affect their applications.

The oxidation of glycerol into lactic acid using activated carbon with Pd or Pt as heterogeneous catalysts was study. Several reaction parameters were evaluated: catalyst loading, catalyst weight, NaOH/glycerol molar ratio, temperature and reaction time. The textural and structural properties of the carbon supported catalysts (fresh and spent) were evaluated by N 2 adsorption-desorption isotherms at −196 °C, XRD, SEM, EDX, TEM and XPS. It was possible to achieve a glycerol conversion of about 99% with selectivity to lactic acid of 68% and 74% using 10% Pd/C and 5% Pt/C as catalysts, respectively, at 230 °C of reaction temperature. Moreover, Pd/C and Pt/C catalysts were used in five reaction cycles without significant loss of activity, highlighting the great stability of the prepared catalysts.

El estudio de los compuestos metal-orgánicos MOFs ha experimentado un rápido crecimiento en las últimas dos décadas debido a sus interesantes propiedades: flexibilidad en el diseño y funcionalización de sus poros, elevada superficie específica y síntesis menos complejas. Dentro de esta gran familia de materiales, los que contienen Zr como metal activo, rodeado por ligandos de ácido tereftalico (UiO-66) son buenos catalizadores y estables para la esterificación de ácido levulínico con etanol, con actividades comparables a otros catalizadores ácidos sólidos. El objetivo del presente trabajo fue sintetizar compuestos del tipo MOF UIO-66 con circonio como precursor metálico y tetracloruro de circonio como fuente metálica, empleando una ruta alternativa de síntesis, con condiciones más favorables desde el punto de vista económico y ambiental. Es por ello que se propone el uso de solventes alternativos. La síntesis se realizó mediante el método solvotermal a 120 °C durante 24hs. Se utilizó dimetilformamida como solvente y se reemplazó entre un 0 y 75%, de dicho solvente, por acetona. Estos materiales luego se evaluaron catalíticamente en la reacción de esterificación del ácido levulínico con etanol. Las propiedades del material fueron caracterizadas por difracción de rayos X, microscopía electrónica de barrido, espectroscopia infrarroja, espectroscopía fotoelectrónica de rayos X, espectroscopia de emisión atómica por plasma de microondasy área superficial. El progreso de la reacción fue seguido por cromatografía gaseosa y espectroscopía de masa. El material más activo fue el MOF100% con 17,42% de conversión y 27,17 % de selectividad a levulinato de etilo.

In this work, we utilize a top-down approach to synthesize nitrogen doped graphene quantum dots from a 3D-graphene precursor via an eco-friendly hydrothermal method. The nanoparticles obtained showed a 2–3 nm diameter and well dispersion behavior in aqueous media. The reaction mechanism of insertion of nitrogen from polyvinylpolypyrrolidone onto the 3D-graphene structure, via an esterification reaction, was studied by the density functional theory, in addition, the kinetic and thermodynamic magnitudes of the reaction was analyzed with the help of Eyring's transition state theory and statistical thermodynamics. After analysis by ss-NMR and XPS spectroscopies, the functional groups involved in this process were characterized, and N was found mainly as amide/amine groups. Fluorescence emission, which exhibited a red shift (552 nm) and an emission maximum at 512 nm when excited at 480 nm, demonstrated a low stoke shift (Δλ = 32 nm), explained by the proposed structural model. Fil: Algarra, Manuel. Universidade Da Madeira; Portugal Fil: Moreno, Virginia. Universidad de Castilla-La Mancha; España Fil: Lazaro Martinez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentina Fil: Rodríguez-Castellón, Enrique. Universidad de Málaga. Facultad de Ciencias; España Fil: Soto, Juan. Universidad de Málaga; España Fil: Morales, Julián. Universidad de Málaga; España Fil: Benítez, Almudena. Universidad de Córdoba; España

Reports about the influence of cerium-oxide nanoparticles (nCeO2) on plants are contradictory due to their positive and negative effects on plants. Surface modification may affect the interaction of nCeO2 with the environment, and hence its availability to plants. In this study, the uncoated and glucose-, levan-, and pullulan-coated nCeO2 were synthesized and characterized. The aim was to determine whether nontoxic carbohydrates alter the effect of nCeO2 on the seed germination, plant growth, and metabolism of wheat and pea. We applied 200 mgL-1 of nCeO2 on plants during germination (Ger treatment) or three week-growth (Gro treatment) in hydroponics. The plant response to nCeO2 was studied by measuring changes in Ce concentration, total antioxidative activity (TAA), total phenolic content (TPC), and phenolic profile. Our results generally revealed higher Ce concentration in plants after the treatment with coated nanoparticles compared to uncoated ones. Considering all obtained results, Ger treatment had a stronger impact on the later stages of plant development than Gro treatment. The Ger treatment had a stronger impact on TPC and plant elongation, whereas Gro treatment affected more TAA and phenolic profile. Among nanoparticles, levan-coated nCeO2 had the strongest and positive impact on tested plants. Wheat showed higher sensitivity to all treatments. Fil: Milenkovic, Ivana. Universidad de Belgrado; Serbia Fil: Mitrovic, Aleksandra. Universidad de Belgrado; Serbia Fil: Algarra, Manuel. Universidad de Madeira; Portugal Fil: Lazaro Martinez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentina Fil: Rodríguez Castellón, Enrique. Universidad de Málaga. Facultad de Ciencias; España Fil: Maksimovic, Vuk. Universidad de Belgrado; Serbia Fil: Spasic, Sladana Z.. Universidad de Belgrado; Serbia Fil: Beskoski, Vladimir P.. Universidad de Belgrado; Serbia Fil: Radotic, Ksenija. Universidad de Belgrado; Serbia

The efficient oxidation of alcohols remains a challenge, especially when using solid heterogeneous catalysts. Herein, the catalytic activity of mechanochemically prepared iron and palladium particles on various supports are compared for the oxidation of cinnamyl alcohol to cinnamaldehyde and benzaldehyde in acetonitrile using aqueous hydrogen peroxide as the oxidant assisted by microwave irradiation. Important insights into the mechanism of the reaction towards the differently observed products have been provided.

Investigations into nanoporous materials and their applications continue to afford a wealth of novel materials and new applications [...]

A metal-free oxygen reduction reaction (ORR) electrocatalyst with outstanding performance was obtained through an easy and one-pot synthesis of hemoglobin functionalized fructose@graphene-oxide (GO) nanocomposites. The active pyridinic nitrogen sites of the highly unfolded proteins together with the excellent electronic properties of GO appears to be the main factors causing the improved electrocatalytic activity.

Polyethylenimine (PEI)-decorated gold nanoparticles (AuNP) were electrodeposited on conductive surfaces in one-step procedure. Solution-state NMR evidenced that chloride from PEI.HCl was partially exchanged by AuCl 4 − prior to AuNP formation. XPS studies indicated the presence of Au° together with the interaction between AuNP with nitrogen atoms of the PEI polymer. The particle size by DLS was 49 nm. The electrochemical behavior of bare electrode and of glassy carbon electrode modified with PEI-decorated AuNP was compared using [Fe(CN) 6 ] 3-/4- redox probe, to determine the potential role of the nanomaterial and of the polymer in the detection of proteins. The most relevant experimental variables from cyclic voltammetry (CV), square-wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) were used for the characterization of protein uptake. The adsorption by electrostatic interaction between the biomolecules and the positively charged polymer (PEIH + ) affected negatively the current response (Ip) of the probe, especially when the negatively charged protein was involved. This platform resulted adequate to immobilize proteins and to characterize this process, for further applications as a tool in bioanalysis or biotechnology. Fil: Lazaro Martinez, Juan Manuel. Universidad de Málaga; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentina Fil: Byrne, Agustin Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentina Fil: Rodríguez Castellón, Enrique. Universidad de Málaga; España Fil: Manrique, Julieta Marina. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales y Ciencias de la Salud - Sede Trelew. Laboratorio de Virología y Genética Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Jones, Leandro Roberto. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales y Ciencias de la Salud - Sede Trelew. Laboratorio de Virología y Genética Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Campodallorto, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentina

Carbon Dots (CDs) were obtained using a hydrothermal method and used for the detection of fingerprints through fluorescent imaging. Synthesized CDs exhibited a brightness emission at 495 nm, which was related to their structural and chemical properties. The results of detailed surface characterizations by XPS, ss-NMR and fluorescence spectroscopies, suggested that the negative charge of the functionals groups promoted electrostatic interactions between the charged CDs surface functional groups (amine, amide and carboxylic) and the secretion components present in the thin layer of fluid left on the surface upon its direct contact with human fingers. The obtained results were validated by the scientific protocol of the Police Automated Fingerprint Identification System (AFIS) based on a biometric identification. Fil: Milenkovic, Ivana. University of Belgrade; Serbia Fil: Algarra, Manuel. Universidad de Málaga; España. Universidade Da Madeira; Portugal Fil: Alcoholado, Cristina. Universidad de Málaga; España Fil: Cifuentes, Manuel. Universidad de Málaga; España Fil: Lazaro Martinez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentina Fil: Rodríguez Castellón, Enrique. Universidad de Málaga; España Fil: Mutavdzic, Dragosav. University of Belgrade; Serbia Fil: Radotic, Ksenija. University of Belgrade; Serbia Fil: Bandosz, Teresa J.. The City College of New York; Estados Unidos

This work presents the physicochemical characterization and activity of zirconia-supported silver catalysts for the oxidation of pollutants present in diesel engine exhaust (propane, propene, naphthalene and soot). A series of silver-supported catalysts AgxZ (x = 1, 5 and 10 wt.%, Z = zirconia) were prepared, which were studied by various characterization techniques. The results show that silver is mainly found under the form of small metal nanoparticles (&lt, 10 nm) dispersed over the support. The metallic phase coexists with the AgOx oxidic phases. Silver is introduced onto the zirconia, generating Ag&ndash, ZrO2 catalysts with high activity for the oxidation of propene and naphthalene. These catalysts also show some activity for soot combustion. Silver species can contribute with zirconia in the catalytic redox cycle, through a synergistic effect, providing sites that facilitate the migration and availability of oxygen, which is favored by the presence of structural defects. This is a novel application of the AgOx&ndash, Ag/ZrO2 system in the combustion reaction of propene and naphthalene. The results are highly promising, given that the T50 values found for both model molecules are quite low.

Graphene nanosheets are a promising scaffold to accommodate S for achieving high performanceLi/S battery. Nanosheet activation is used as a viable strategy to induce a micropore system and further improve the battery performance. Accordingly, chemical activation methods dominate despite the need of multiple stages, which slow down the process in addition to making them tiresome. Here, a three-dimensional (3D)N-doped graphene specimen was physically activated with CO2, a clean and single step process, and used for the preparation of a sulfur composite (A-3DNG/S). The A-3DNG/S composite exhibited outstanding electrochemical properties such as an excellent rate capability (1,000 mAh·g─1at 2C), high reversible capacity and cycling stability (average capacity ~ 800 mAh·g─1at 1C after 200cycles), values which exceed those measured in chemically activated graphene. Therefore, these results support the use of physical activation as a simple and efficient alternative to improve the performance of carbons as an S host for high-performance Li-S batteries.

[EN] We report on the effect of NiO-support interactions on the chemical nature of Ni species in a series of supported NiO catalysts for the ODH of ethane. SiO2, TiO2-anatase, a high surface area TiO2 and a porous clay hetero-structure (PCH) with TiO2 and SiO2 pillars were used as supports, which led to a selectivity to ethylene in the range 30-90% over supported NiO catalysts. The catalysts were characterized by means of XRD, N-2-Adsorption, H-2-TPR, XPS and in situ (under H-2 reductive atmosphere) and ex situ XAS spectroscopy. The catalytic performance of supported materials is discussed in terms of their reducibility and specific reduction kinetics, but also taking into account the specific chemical nature of Ni species on each catalyst. The influence of the particle size and the presence of Ni and O vacancies on the catalytic performance in the ODH of ethane is inferred., Authors would like to thank the DGICYT in Spain CTQ2015-68951-C3-1-R, CTQ2015-68951-C3-3-R, CTQ2012-37925-C03-2 and ENE2017-88818-C2-1-R. Also authors want to acknowledge the ALBA Synchrotron Light Source (Project ID: 2015021258 at CLAESS beamline). Authors from ITQ thank Project SEV-2016-0683 for financial support. D. D. also thanks MINECO and Severo Ochoa Excellence Program for his fellowship (SVP-2014-068669). Authors from UV thank the University of Valencia (UV-INV-AE16-484416 project) and MINECO (MAT2017-84118-C2-1-R project) for funding.

The present work explores the production of isopropyl levulinate from furfural by a two-step microwave assisted cascade process. Furfural is a versatile biomass-derived industrial feedstock with high annual production volume. Alkyl levulinates are promising bio-based molecules with several applications in many sectors, in particular, as biofuels, blended with transportation fuels including biodiesel, these compounds can significantly reduce the formation of soot in engines. Thus, in the first step, the catalytic transfer hydrogenation of furfural to furfuryl alcohol was studied employing a simply “ad hoc” synthesized magnetically recoverable Cu catalyst and 2-propanol as H-donor. Subsequently, the alcoholysis of the previously obtained liquors rich in furfuryl alcohol or of neat furfuryl alcohol solutions to isopropyl levulinate was investigated using commercial solid acid catalysts such as niobium phosphate and Amberlyst sulfonic resins (A15 and A70). The cascade process resulted feasible leading to good furfuryl alcohol yields in the transfer hydrogenation process with Cu-Fe3O4 magnetic catalyst using much lower Cu to furfural molar ratios than commonly reported. The subsequent alcoholysis step of furfuryl alcohol-rich liquors was highly efficient with A70 resin even in presence of unreacted furfural from the first step.

[EN] The present paper shows the influence of Cu-content in Cu-promoted V2O5 catalysts on both the physicochemical characteristics of catalysts and their catalytic performance in the partial oxidation of hydrogen sulfide. Both, the catalytic activity for H2S conversion and the selectivity to sulfur increased when increasing the Cu/V ratio of catalysts. The best catalyst gives a selectivity to sulfur at ca. 98% at total conversion of H2S. According to the characterization results (XRD, FTIR), V2O5 is partially transformed into vanadium oxide bronze, i.e. beta-Cu0.261V2O5, up to Cu/V ratios of 0.25. For higher Cu/V ratios, CuV2O6 and beta-Cu0.261V2O5 are observed. In the same way, the reducibility of V-species increased when increasing the Cu/V ratio of catalysts. On the other hand, the characterization of used catalysts indicates the transformation of V2O5 into V4O9, whereas the vanadium oxide bronze is stable under the studied reaction. The catalytic results are explained on the basis of the nature of crystalline phases and the presence of V5+-O-V4+ pairs in the more selective catalysts., The authors would like to acknowledge the Spanish MINECO Projects (CTQ2015-68951-C3-1-R and CTQ2015-68951-C3-3-R) and Severo Ochoa Program (SEV-2016-0683), and FEDER funds, for financial support. LRR thanks the MINECO for a predoctoral contract.

The oxygen reduction (ORR) and hydrogen evolution (HER) reactions are the most important cathodic processes involved in fuel cell and water splitting technologies, respectively. The development of bifunctional electrocatalyst materials plays a key role in the rapid advancement of these hydrogen-based renewable energy strategies. This work proposes citrate-stabilized gold nanoparticles (AuNPs) as a bifunctional electrocatalyst for ORR and HER. The capping ligand has a great influence on their resulting electrocatalytic performance. A simple ligand exchange method based on concentration gradients has been optimized. The surface structure of the different ligand-stabilized AuNPs was inferred by lead underpotential deposition (Pb-UPD). Static and dynamic electrochemical studies for both ORR and HER have been performed using different ligand-stabilized AuNPs as electrocatalysts, demonstrating that the citrate ligand confers the best performance. This work suggests that non-doped chemically synthesized AuNPs may be suitable as a bifunctional electrocatalyst in fuel cells and hydrogen production.

Improvement of processes starting from renewable feedstocks to produce chemicals and biofuels up to now derived from fossil carbon feedstocks is paramount to creating environmentally sustainable industrial processes. Guerbet condensation of ethanol to give n-butanol represents a turning point not only respect to the traditional petrochemical “oxo” process, but also to the bio-chemical path (Acetone Butanol Ethanol “ABE” process). In this work, different Cu/Mg/Al hydrotalcite-derived mixed oxides catalysts, with Cu atomic content in the range 7.6–1.0%, were synthetised, characterized, and tested for the Guerbet reaction. The adopted catalysts are easy to produce, and based on available, cheap and non-toxic metals. Tailoring Cu-content in hydrotalcite-derived Cu/Mg/Al mixed oxides allowed us to selectively address this reaction towards n-butanol formation, highlighting how a low Cu-content favours the condensation to n-butanol and higher alcohols, in particular n-hexanol, decreasing the ester formation. The Guerbet selective co-production of [n-butanol + n-hexanol] is economically even more attractive than that of the sole n-butanol, being both saleable products. Good catalytic performances to n-butanol and n-hexanol were achieved, in a batch process carried out under subcritical conditions. These catalysts have required a simple procedure of recovery, showing good recyclability, in term of catalytic performances to give the target products, thus opening the way to applicative perspectives.

Semi-liquid configuration of sulfur cell is proposed as simple strategy to develop high-energy lithium battery. Two solutions of Li2S8 in diethylene glycol dimethyl ether (DEGDME), containing either lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or lithium trifluoromethansulfonate (LiCF3SO3), are studied as catholytes for Li/S cells exploiting the polysulfides electrochemical reaction at about 2.2 V vs. Li+/Li. X-ray photoelectron spectroscopy (XPS) and thermal analyses, respectively, reveal composition and high-temperature stability of the catholyte solutions. Ad hoc study conducted by impedance spectroscopy, voltammetry, and galvanostatic techniques suggests well suitable characteristics in terms of Li+-transport ability, electrochemical stability window, and electrode/electrolyte interphase features. Cells with sulfur loading ranging from about 3 to 5 mg cm−2 into the solution are successfully studied with remarkable performances in terms of current rates, efficiency and cycle life. Hence, the lithium cells based on the catholyte deliver maximum capacity of the order of 1100 mAh gS −1 at C/10 rate and stable capacity of about 800 mAh gS −1 at C/3 rate with Coulombic efficiency exceeding 99%. Therefore, the catholyte solutions studied herein are considered as a well suitable candidate for high-energy storage in next generation systems, such as the intriguing hybrid and electric vehicles

Sorbitol is a sugar alcohol of great importance in cosmetic, food and pharmaceutical industry as well as the production of biopolymers. This work aimed at the synthesis of sorbitol from the hydrogenation of glucose using Ru/Nb2O5 catalysts in the amorphous and crystalline phases. The catalysts were synthesized from the wet impregnation method and characterized by N2 adsorption isotherms, TGA/DTG, EDXRF, XRD, TPR-H2, XPS and SEM. The catalytic tests presented results of high conversion rates of glucose reaching 85 % and 99 % of selectivity to sorbitol when using Nb2O5 in the crystalline form as support, and 53 % and 55 % in the conversion and selectivity, respectively, when the amorphous phase of Nb2O5 was used as support. The structural modification of the catalytic support positively favored the catalyst activity and sorbitol production, allowing the formation of nanometric particles of the active metal on the surface alongside the increase of the mesoporosity, thereby facilitating the transport of reagents.

With the growing demand of gold for research laboratories and industrial technologies, there is high needed to extract gold from related waste other than natural resources. Herein, we designed a novel adsorbent denoted as PCN-222-MBA (Thiol-functionalized PCN-222), by functionalizing Zr6-nodes of PCN-222 (PCN = Porous Coordination Network) with 4-mercaptobenzoic acid (MBA) through solvent-assisted ligand incorporation (SALI) approach for selective and facile extraction of gold ions from aqueous media. The mesoporous MOF was characterized by different techniques. The performance of PCN-222-MBA as solid adsorbent was assessed under batch conditions, with significant parameters studied and optimized. The maximum adsorption capacity of the respective adsorbent was 714.3 mg/g at pH 6.1 and 1 min. PCN-222-MBA exhibited high affinity for Au(III) than other coexisting ions and could be regenerated at least six cycles. Gold ions were also extracted and determined in real samples.

The production of biodiesel from acidic non-edible oil and waste lipid feedstocks has the drawback of forming soaps in the conventional transesterification process. A solution is the esterification reaction that uses superacid homogenous catalysts; however, it generates dangerous effluents. To overcome this, heterogeneous acid catalysts such as heteropolyacid supported on activated carbon have been studied for the production of biofuel. Due to its high surface area, the activated carbon allows high dispersion of the active phase. The aim of this work was to study the esterification of oleic acid over 12-tungstophosphoric acid (HPW) supported on activated carbon derived from passion fruit biomass (ACP), prepared by chemical activation using ZnCl2. The composites (HPW/ACP) were prepared containing 10–30 wt% of HPW by following two procedures: aqueous impregnation method and incipient moisture. The results showed that the activated carbon prepared from the residue of the passion fruit seed presented a high surface area (465 m2. g−1) and that the HPW impregnation method on activated carbon was a decisive factor on the catalyst performance. XPS, SEM, NMR and N2 adsorption-desorption results showed that in the catalyst obtained by aqueous impregnation (HPW/ACP) surface area decreased (50 m2 g−1), HPW was highly dispersed in the internal pores of the ACP support and presented superior acidity. The incipient moisture impregnation (HPW/IACP) formed HPW particles on the external surface of the support with little interaction among them, resulting in surface area of 90 m2 g−1. The best result of oleic acid esterification with methanol led to 86.4% conversion with catalyst HPW30/ACP, at 100 °C, after 2 h of reaction. The leaching of HPW active phase after the reaction was low ∼1.0–2.6%. This study showed the importance of the HPW impregnation method on activated carbon to obtain a more stable and more active catalyst for the production of biodiesel. A detailed analysis of the catalyst synthesis from a fruit industry residue demonstrated the possibility of operating in a closed-loop system towards cleaner production.