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Advanced parametrisation of phase change materials through kinetic approach

Lizana, J; Perejon, A; Sanchez-Jimenez, PE; Perez-Maqueda, LA
Journal of Energy Storage, 44 (2021) 103441
Reactividad de Sólidos


Phase change materials (PCM) have been widely investigated for heat storage and transfer applications. Numerous numerical simulation approaches have been proposed for modelling their behaviour and predicting their performance in thermal applications. However, simulation approaches do not consider the kinetics of the phase transition processes, compromising the accuracy of their predictions. The phase change is a kinetically driven process in which both the reaction rate and the reaction progress depend on the heating schedule. This work evaluates and parametrises the influence of kinetics in the melting and crystallisation behaviour of a well-known PCM, PEG1500, and compares potential discrepancies with common phase change parametrisation alternatives. The kinetic dependence was experimentally evaluated through differential scanning calorimetry (DSC). The kinetic parameters required for modelling the kinetics of the processes were determined by both model-free and model-fitting procedures following ICTAC (International Confederation for Thermal Analysis and Calorimetry) recommendations. Then, the phase transition was parametrised through a kinetic model and compared with three conventional phase transition models: linear without hysteresis, non-linear without hysteresis, and non-linear with hysteresis. The statistical comparison between models demonstrates the higher accuracy of the kinetic approach to correctly represent the partial enthalpy distribution of latent heat storage materials during alternative phase change rates, obtaining a coefficient of determination (R-2) of 0.80. On the other hand, the accuracy of kinetic-independent models is limited to the range from 0.40 to 0.61. The results highlight the high discrepancies of conventional models compared to the kinetic approach and provide criteria and guidelines for efficient kinetic modelling of phase change in heat transfer evaluations.

Diciembre, 2021 | DOI: 10.1016/j.est.2021.103441

Fabrication and characterization of FeCoNiCrMn,(Al) high entropy alloy based (Ti,Ta,Nb)(C,N) cermet

Real, C; Alcala, MD; Trigo, I; Fombella, I; Cordoba, JM
International Journal of Refractory Metals & Hard Materials, 101 (2021) 105694
Reactividad de Sólidos


From nanostructured mechanically synthesized powder a set of FeCoNiCrMn,(Al) based (Ti,Ta,Nb)(C,N) cermets were fabricated and sintered by a pressureless procedure. Highly dense cermets were obtained, and the nature of chemical change, microstructure, mechanical properties and coarsening kinetic of ceramic phase were characterized by image analysis, microindentation, scanning electron microscopy and X-ray diffraction. The design of the material was performed using a set of three different chemical cermet composition and three different sintering temperatures, or comparative purposes.

Diciembre, 2021 | DOI: 10.1016/j.ijrmhm.2021.105694

White, blue, violet, and other colors from Tm3+/Tb3+/Eu3+ co-doped polymorph SrAl2O4 films, deposited by ultrasonic spray pyrolysis technique

Calderon-Olvera, RM; Garcia-Hipolito, M; Alvarez-Fregoso, O; Alvarez-Perez, MA; Baez-Rodriguez, A; Ramos-Brito, F; Garcia-Velasco, AC; Falcony, C
Opticalls Materials
Materiales Coloidales


SrAl2O4: Tm3+, SrAl2O4: (Tb3+; Eu3+) and SrAl2O4: (Tb3+; Eu3+; Tm3+) films were deposited by ultrasonic spray pyrolysis (USP) method at 550. C and subsequently heat-treated at 800 degrees C. XRD characterization showed a monoclinic/hexagonal polymorph phase of these films with orthorhombic Sr4Al14O25 as secondary phase. The incorporation of Tm3+ ions in strontium aluminate host lattice generated emissions of blue color for photoluminescence and violet color for cathodoluminescence. The violet emission was associated to the electronic transition from I-1(6) energy level of Tm3+. Photoluminescence of the SrAl2O4: (Tb3+; Eu3+) films resulted in two different colors, white emission was observed when excited with 210 nm and bluish-white emission was achieved by exciting with 275, and 286 nm. When three dopant ions (Tm3+; Tb3+; Eu3+) were incorporated inside strontium aluminate host lattice, it was observed (exciting under 252 nm) white photoluminescence emission (x = 0.3377, y = 0.3294); for excitation wavelengths (lambda(exc)) = 262, 315 and 375 nm, emissions in different shades of blue-green were achieved. Quantum efficiencies between 48 and 57% were obtained.

Diciembre, 2021 | DOI: 10.1016/j.optmat.2021.111737

Designed organomicaceous materials for efficient adsorption of iodine

Osuna, FJ; Pavon, E; Pazos, MC; Alba, MD
Journal of Environmental Chemical Engineering, 9 (2021) 106577
Materiales de Diseño para la Energía y Medioambiente


The anionic iodine I-129 has a significant contribution to overall long-term dose resulting from the nuclear waste storage and its immobilization by clay barrier is crucial. Organoclays have been tested as ideal adsorption materials, being the clay layer charge and the length and type of organic molecules the most relevant parameters affecting the adsorption. In this work, a family of designed organomicas are explored in term of iodine adsorption capacity. Their adsorption capacities were always higher than that of the traditional clays and organoclays. C-18-M4 shows a maximum monolayer adsorption capacity one order of magnitude higher than natural organoclays, with a free energy typical of physical adsorption and adsorption sites of high affinity. However, its surface is not homogeneous in terms of stability constant according to the Scatchard adsorption parameters. Hence, this study can provide a guidance for the design and construction of ultrahigh-capacity iodine adsorbents.

Diciembre, 2021 | DOI: 10.1016/j.jece.2021.106577

LaFeO3 Modified with Ni for Hydrogen Evolution Via Photocatalytic Glucose Reforming in Liquid Phase

G. Iervolino; V. Vaiano; D. Sannino; F. Puga; J.A. Navío; M.C. Hidalgo
Catalysts, 11 (2021) 1558
Fotocatálisis Heterogénea: Aplicaciones


In this work, the optimization of Ni amount on LaFeO3 photocatalyst was studied in the photocatalytic molecular hydrogen production from glucose aqueous solution under UV light irradiation. LaFeO3 was synthesized via solution combustion synthesis and different amount of Ni were dispersed on LaFeO3 surface through deposition method in aqueous solution and using NaBH4 as reducing agent. The prepared samples were characterized with different techniques: Raman spectroscopy, UltraViolet-Visible Diffuse Reflectance Spettroscopy (UV–Vis-DRS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), X-ray Fluorescence (XRF), Transmission Electron microscopy (TEM), and Scanning Electron microscopy (SEM) analyses. For all the investigated photocatalysts, the presence of Ni on perovskite surface resulted in a better activity compared to pure LaFeO3. In particular, it is possible to identify an optimal amount of Ni for which it is possible to obtain the best hydrogen production. Specifically, the results showed that the optimal Ni amount was equal to nominal 0.12 wt% (0.12Ni/LaFeO3), for which the photocatalytic H2 production was equal to 2574 μmol/L after 4 h of UV irradiation. The influence of different of photocatalyst dosage and initial glucose concentration was also evaluated. The results of the optimization of operating parameters indicated that the highest molecular hydrogen production was achieved on 0.12Ni/LaFeO3 sample with 1.5 g/L of catalyst dosage and 1000 ppm initial glucose concentration. To determine the reactive species that play the most significant role in the photocatalytic hydrogen production, photocatalytic tests in the presence of different radical scavengers were performed. The results showed that •OH radical plays a significant role in the photocatalytic conversion of glucose in H2. Moreover, photocatalytic tests carried out with D2O instead of H2O evidenced the role of water molecules in the photocatalytic production of molecular hydrogen in glucose aqueous solution.

Diciembre, 2021 | DOI: 10.3390/catal11121558

Nanophotonics for current and future white light-emitting devices

Galisteo-Lopez, JF; Lozano, G
Journal of Applied Physics, 130 (2021) 200901
Materiales Ópticos Multifuncionales


Photonic nanostructures have proven useful to enhance the performance of a wide variety of materials and devices for sensing, catalysis, light harvesting, or light conversion. Herein, we discuss the role of nanophotonics in current and next-generation designs of white light-emitting diodes (LEDs). We discuss recent developments on luminescent materials designed as alternatives to rare earth-doped inorganic microcrystals, i.e., phosphors, for color conversion in LEDs, which has opened the door to the integration of resonant photonic architectures. Nanophotonics enables the devised light-matter interaction with luminescent materials in the nanoscale, which allows providing emitting devices with both enhanced performance and novel functionalities to tackle technological challenges

Noviembre, 2021 | DOI: 10.1063/5.0065825

Zinc Polyaleuritate Ionomer Coatings as a Sustainable, Alternative Technology for Bisphenol A-Free Metal Packaging

Morselli, D; Cataldi, P; Paul, UC; Ceseracciu, L; Benitez, JJ; Scarpellini, A; Guzman-Puyol, S; Heredia, A; Valentini, P; Pompa, PP; Marrero-López, D; Athanassiou, A; Heredia-Guerrero, A
ACS Sustainable Chemistry & Engineering, 9 (2021) 15484-15495
Materiales de Diseño para la Energía y Medioambiente


Sustainable coatings for metal food packaging were prepared from ZnO nanoparticles (obtained by the thermal decomposition of zinc acetate) and a naturally occurring polyhydroxylated fatty acid named aleuritic (or 9,10,16-trihydroxy-hexadecanoic) acid. Both components reacted, originating under specific conditions zinc polyaleuritate ionomers. The polymerization of aleuritic acid into polyaleuritate by a solvent-free, melt polycondensation reaction was investigated at different times (15, 30, 45, and 60 min), temperatures (140, 160, 180, and 200 degrees C), and proportions of zinc oxide and aleuritic acid (0:100, 5:95, 10:90, and 50:50, w/w). Kinetic rate constants calculated by infrared spectroscopy decreased with the amount of Zn due to the consumption of reactive carboxyl groups, while the activation energy of the polymerization decreased as a consequence of the catalyst effect of the metal. The adhesion and hardness of coatings were determined from scratch tests, obtaining values similar to robust polymers with high adherence. Water contact angles were typical of hydrophobic materials with values >= 94 degrees. Both mechanical properties and wettability were better than those of bisphenol A (BPA)-based resins and most likely are related to the low migration values determined using a hydrophilic food simulant. The presence of zinc provided a certain degree of antibacterial properties. The performance of the coatings against corrosion was studied by electrochemical impedance spectroscopy at different immersion times in an aqueous solution of NaCl. Considering the features of these biobased lacquers, they can be potential materials for bisphenol A-free metal packaging.

Noviembre, 2021 | DOI: 10.1021/acssuschemeng.1c04815

Recent Advances in Alkaline Exchange Membrane Water Electrolysis and Electrode Manufacturing

Lopez-Fernandez, E; Sacedon, CG; Gil-Rostra, J; Yubero, F; Gonzalez-Elipe, AR; De Lucas-Consuegra, A
Molecules, 26 (2021) 6326
Nanotecnología en Superficies y Plasma


Water electrolysis to obtain hydrogen in combination with intermittent renewable energy resources is an emerging sustainable alternative to fossil fuels. Among the available electrolyzer technologies, anion exchange membrane water electrolysis (AEMWE) has been paid much attention because of its advantageous behavior compared to other more traditional approaches such as solid oxide electrolyzer cells, and alkaline or proton exchange membrane water electrolyzers. Recently, very promising results have been obtained in the AEMWE technology. This review paper is focused on recent advances in membrane electrode assembly components, paying particular attention to the preparation methods for catalyst coated on gas diffusion layers, which has not been previously reported in the literature for this type of electrolyzers. The most successful methodologies utilized for the preparation of catalysts, including co-precipitation, electrodeposition, sol-gel, hydrothermal, chemical vapor deposition, atomic layer deposition, ion beam sputtering, and magnetron sputtering deposition techniques, have been detailed. Besides a description of these procedures, in this review, we also present a critical appraisal of the efficiency of the water electrolysis carried out with cells fitted with electrodes prepared with these procedures. Based on this analysis, a critical comparison of cell performance is carried out, and future prospects and expected developments of the AEMWE are discussed.

Noviembre, 2021 | DOI: 10.3390/molecules26216326

Recent Advances in the Bronsted/Lewis Acid Catalyzed Conversion of Glucose to HMF and Lactic Acid: Pathways toward Bio-Based Plastics

Megias-Sayago, C; Navarro-Jaen, S; Drault, F; Ivanova, S
Catalysts, 11 (2021) 1395
Química de Superficies y Catálisis


One of the most trending topics in catalysis recently is the use of renewable sources and/or non-waste technologies to generate products with high added value. That is why, the present review resumes the advances in catalyst design for biomass chemical valorization. The variety of involved reactions and functionality of obtained molecules requires the use of multifunctional catalyst able to increase the efficiency and selectivity of the selected process. The use of glucose as platform molecule is proposed here and its use as starting point for biobased plastics production is revised with special attention paid to the proposed tandem Bronsted/Lewis acid catalysts.

Noviembre, 2021 | DOI: 10.3390/catal11111395

Polyaniline coated tungsten trioxide as an effective adsorbent for the removal of orange G dye from aqueous media

Hsini, A.; Naciri, Y.; Bouziani, A.; Aarab, N.; Essekri, A; Imgharn, A.; Laabd. M.; Navío, J.A.;Puga, F.; Lakhmirid, R.; Albourine, A.
RSC Advances, 11 (2021) 31272-31283
Fotocatálisis Heterogénea: Aplicaciones


In this work, the core–shell PANI@WO3 composite was obtained from the reaction of aniline monomer polymerization with WO3 particles; sodium persulfate was used as an oxidant. Various analytical techniques such as scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-prepared PANI@WO3 adsorbent, which well confirmed that the WO3 particles were coated by polyaniline polymer. The PANI@WO3 composite was tested as an adsorbent to remove reactive orange G (OG) for the first time. pH, adsorbent dose, contact time, initial dye concentration, and temperature were systematically investigated in order to study their effect on the adsorption process. The experimental findings showed that the PANI@WO3 composite has considerable potential to remove an aqueous OG dye. Langmuir and Freundlich's models were used to analyze the equilibrium isotherms of OG dye adsorption on the PANI@WO3 composite. As a result, the best correlation of the experimental data was provided by the Langmuir model, and the maximum capacity of adsorption was 226.50 mg g−1. From a thermodynamic point of view, the OG dye adsorption process occurred spontaneously and endothermically. Importantly, PANI@WO3 still exhibited an excellent adsorption capability after four regeneration cycles, indicating the potential reusability of the PANI@WO3 composite. These results indicate that the as prepared PANI@WO3 composite could be employed as an efficient adsorbent and was much better than the parent material adsorption of OG dye.

Noviembre, 2021 | DOI: 10.1039/D1RA04135E

Ultrastrong Exciton-Photon Coupling in Broadband Solar Absorbers

Bujalance, C; Esteso, V; Calio, L; Lavarda, G; Torres, T; Feist, J; Garcia-Vidal, FJ; Bottari, G; Miguez, H
Journal of Physical Chemistry Letters, 12 (2021) 10706-10712
Materiales Ópticos Multifuncionales


The recent development of organic polaritonic solar cells, in which sunlight absorbers and photon modes of a resonator are hybridized as a result of their strong coupling, has revealed the potential this interaction offers to control and enhance the performance of these devices. In this approach, the photovoltaic cell is built in such a way that it also behaves as an optical cavity supporting spectrally well-defined resonances, which match the broad absorption bands of the dyes employed. Herein we focus on the experimental and theoretical analysis of the specific spectral and angular optical absorption characteristics of a broadband light harvester, namely a subphthalocyanine, when operating in the ultrastrong coupling regime. We discuss the implications of having a broad distribution of oscillator strengths and demonstrate that rational design of the layered structure is needed to optimize both the spectral and the angular response of the sunlight harvester dye.

Noviembre, 2021 | DOI: 10.1021/acs.jpclett.1c02898

K-Promoted Ni-Based Catalysts for Gas-Phase CO2 Conversion: Catalysts Design and Process Modelling Validation

Gandara-Loe, J; Portillo, E; Odriozola, JA; Reina, TR; Pastor-Perez, L
Frontiers in Chemistry, 9 (2021) 785571
Química de Superficies y Catálisis


The exponential growth of greenhouse gas emissions and their associated climate change problems have motivated the development of strategies to reduce CO2 levels via CO2 capture and conversion. Reverse water gas shift (RWGS) reaction has been targeted as a promising pathway to convert CO2 into syngas which is the primary reactive in several reactions to obtain high-value chemicals. Among the different catalysts reported for RWGS, the nickel-based catalyst has been proposed as an alternative to the expensive noble metal catalyst. However, Ni-based catalysts tend to be less active in RWGS reaction conditions due to preference to CO2 methanation reaction and to the sintering and coke formation. Due to this, the aim of this work is to study the effect of the potassium (K) in Ni/CeO2 catalyst seeking the optimal catalyst for low-temperature RWGS reaction. We synthesised Ni-based catalyst with different amounts of K:Ni ratio (0.5:10, 1:10, and 2:10) and fully characterised using different physicochemical techniques where was observed the modification on the surface characteristics as a function of the amount of K. Furthermore, it was observed an improvement in the CO selectivity at a lower temperature as a result of the K-Ni-support interactions but also a decrease on the CO2 conversion. The 1K catalyst presented the best compromise between CO2 conversion, suppression of CO2 methanation and enhancing CO selectivity. Finally, the experimental results were contrasted with the trends obtained from the thermodynamics process modelling observing that the result follows in good agreement with the modelling trends giving evidence of the promising behaviour of the designed catalysts in CO2 high-scale units.

Noviembre, 2021 | DOI: 10.3389/fchem.2021.785571

Influence of helium incorporation on growth process and properties of aluminum thin films deposited by DC magnetron sputtering

Ibrahim, S; Lahboub, FZ; Brault, P; Petit, A; Caillard, A; Millon, E; Sauvage, T; Fernandez, A; Thomann, Al
Surface & Coatings Technology, 426 (2021)
Materiales Nanoestructurados y Microestructura


The effect of helium content on the morphology, crystallinity, and composition of aluminum films was investigated by depositing He-loaded Al films onto Si substrates via direct current (DC) magnetron sputtering in different Ar/He plasma mixtures. Three different plasma regimes were identified depending on the percentage of He in the gas phase. For a low He to total gas ratio (ΓHe ≤ 70%), the plasma is dominated by argon, where Ar+ ions contribute to sputter out the target atoms. The films deposited in this regime exhibited the classical dense columnar structure and contain very low amount of He (below 2%). Then, as ΓHe increases, helium ions begin to be formed and more fast He neutrals reach the substrate, affecting the film growth. As He amount increased in the gas phase up to 95%, the proportion of He inserted in the films rised up to ⁓15 at. %. Moreover, bubbles/porosity were formed inside the films; those obtained in pure He plasma presented a highly porous fiberform nanostructure. All results confirmed that the modification of the film characteristics was related to the change of the deposition conditions when Ar was replaced by He and to the insertion/release mechanisms of He during the growth.

Noviembre, 2021 | DOI: 10.1016/j.surfcoat.2021.127808

By-products revaluation in the production of design micaceous materials

Mouchet, A; Raffin, F; Cota, A; Osuna, FJ; Pavon, E; Alba, MD
Aplied Clay Science, 214 (2021) 106292
Materiales de Diseño para la Energía y Medioambiente


One of the main objectives of a sustainable development and circular economy is the recycling of by-products generated in industrial and agricultural production processes. One of the possible solution is the use of such by-product materials in the synthesis of environmental adsorbents. In the current research, we present the synthesis of a high charge swelling mica with enhance adsorbent properties from blast furnace slag and rice husk ash. Moreover, to ensure the sustainable synthesis a natural bentoniteis used as Si and Al source. Thus, the current study investigated the fabrication of swelling high charged micas, Na-Mn (n (layer charge) = 2 or 4), from FEBEX bentonite, blast furnace slag and rice husk ash thorough the NaCl melt method. The reaction yield, cation framework distribution and structural characteristic of micas have been studied thorough X-ray Diffraction and Solid State Nuclear Magnetic Resonance. The yields of Na-Mn synthesis and degree of purity of the mica depends on the nature of these precursors. Thus, a sustainable, non-expensive and environmental friendly process has been evaluated.

Noviembre, 2021 | DOI: 10.1016/j.clay.2021.106292

NaY(MoO4)(2)-based nanoparticles: synthesis, luminescence and photocatalytic properties

Nunez, NO; Gomez-Gonzalez, E; Calderon-Olvera, RM; Becerro, AI; Colon, G; Ocana, M
Dalton Transactions, 50 (2021) 16539-16547
Materiales Coloidales



We report on a novel synthesis method, which produces NaY(MoO4)(2) nanoparticles having an almost spherical shape and hydrophilic character. The procedure is also suitable for the preparation of NaY(MoO4)(2)-based nanophosphors by doping this host with lanthanide cations (Eu3+, Tb3+ and Dy3+), which, under UV illumination, exhibit intense luminescence whose color is determined by the selected doping cation (red for Eu3+, green for Tb3+ and yellow for Dy3+). The effects of the cations doping level on the luminescent properties are analyzed in terms of emission intensities and luminescent lifetime, to find the optimum phosphors. Finally, the performance of these nanophosphors and that of the undoped system for the photocatalytic degradation of rhodamine B, used as a model compound, is also analyzed.

Noviembre, 2021 | DOI: 10.1039/d1dt02365a

Extraction of microstructural parameters from sculptured thin films nanoindentation

Gaillard, Y; Jimenez-Pique, E; Oliva-Ramirez, M; Rico, VJ; Gonzalez-Elipe, AR
Surface & Coatings Technology, 425 (2021) 127696
Nanotecnología en Superficies y Plasma


This work deals with the indentation analysis of nanocolumnar thin films and the difficulties encountered to deduce relevant mechanical parameters by this methodology. SiO2 thin films prepared by physical vapour oblique angle deposition with different nanocolumnar microstructures have been subjected to indentation analysis. Despite the fact that the films had been made of the same material, deposited on the same substrate and had similar thickness, their indentation responses were different and depended on their particular microstructure. It has been also realised that the measured hardness and elastic modulus variation with the indentation depth were length scale dependent and that there is not a unique analytical thin-film nanoindentation model to extract the mechanical properties from the experimental nanoindentation curves. To overcome these limitations a numerical finite element model (FEM) of the nanocolumnar coatings has been built to figure out the contributions of the different physical phenomena intervening in the indentation process. This FEM simulation relies on a description of the elasto-plastic microstructural units of the coatings and the contact friction interactions between them. Based on this simulation a parametrical representation, incorporating two length scales and the contributions of densification and/or the buckling of nanocolumnar units, has been developed to account for the evolution of the apparent elastic modulus deduced from numerical indentation tests. A Hall-Petch modification of this description considering two length scales instead of the common approximation considering a single length scale has rendered the best agreement with the elastic values determined experimentally. Although, at the present stage, the particular microstructure of the films can not be deduced from the evolution of their elastic moduli with the indentation depth, the obtained results and their interpretation constitute a first though essential step for the elaboration of an inverse analysis methodology capable of correlating microstructure and elastic response of nanocolumnar coatings.

Noviembre, 2021 | DOI: 10.1016/j.surfcoat.2021.127696

Impact of flame confinement with inert ceramic foams on the particulate emissions of domestic heating systems

Ciria, D; Orihuela, MP; Becerra, JA; Chacartegui, R.; Ramirez-Rico, J.
Fuel, 304 (2021) 121264
Materiales y Procesos Catalíticos de Interés Ambiental y Energético


Small solid biomass combustion systems are among the main contributors to the global particulate emissions share, and cheap, efficient abatement systems are not yet available for them. The placement of inert porous material to confine the combustion region is being recently explored as a possible mitigation system for this kind of pollution. However, given the complexity of biomass thermochemical decomposition processes, it is challenging to justify the performance of these systems on the basis of a physicochemical understanding. A foundational experiment-based study is carried out in this work to understand how combustion confinement affects the particulate emissions production mechanisms. A combustion unit was designed and built to systematically test ceramic foams with different porosities: keeping constant airflow and fuel feed rates. A comprehensive characterisation study was carried out on the solid biomass fuel, the temperature profile, the particulate emissions, and the remaining solid residue. The results evidenced that the use of foams has a substantial impact on the temperature distribution in the combustion chamber. The higher the cell density of the foam, the higher and more homogeneous are the temperatures reached in the combustion bed. This fact improved the thermal decomposition process of the pellets due to a better air-fuel mixture, leading to a reduction of the solid particulate matter emissions by more than 70%. These findings suggest that the use of an inert porous material above the combustion region might be a feasible solution for particulate emission control in small-size biomass combustion technology.

Noviembre, 2021 | DOI: 10.1016/j.fuel.2021.121264

Assessing the impact of textural properties in Ni-Fe catalysts for CO2 methanation performance

Gonzalez-Castano, M; de Miguel, JCN; Boelte, JH; Centeno, MA; Klepel, O; Arellano-Garcia, H
Microporous and Mesoporous Materials, 327 (2021) 111405
Química de Superficies y Catálisis


In heterogeneous catalysis, the benefits of employing adequate textural properties on the catalytic performances are usually stated. Nevertheless, the quantification of the extent of improvement is not an easy task since variations on the catalysts' specific areas and pore structures might involve modifications on a number of other surface catalytic features. This study establishes the impact of the catalyst textural properties on the CO2 methanation performance by investigating bimetallic Ni–Fe catalysts supported over carbon supports with different textural properties regarding surface area and pore structure. The comparable metal loading and dispersions attained for all systems enabled establishing forthright relationships between the catalyst textural properties and CO2 methanation rate. Once the influence of the external mass diffusions on the catalysts’ performance was experimentally discarded, the estimated Thiele modulus and internal effectiveness (φ and ηEff) values showed that the catalyst performance was majorly governed by the surface reaction rate whilst the pore size affected in no significant manner within the examined range (Dpore = 10.2 to 5.8 nm). Therefore, the rapport between the catalyst performance and surface area was quantified for the CO2 methanation reaction over Ni–Fe catalysts: increasing the surface area from 572 to 802 m2/g permit obtaining ca. 10% higher CO2 conversions.

Noviembre, 2021 | DOI: 10.1016/j.micromeso.2021.111405

Waterproof-breathable films from multi-branched fluorinated cellulose esters

Tedeschi, G; Guzman-Puyol, S; Ceseracciu, L; Benitez, JJ; Goldoni, L; Koschella, A; Heinze, T; Cavallo, G; Dichiarante, V; Terraneo, G; Athanassiou, A; Metrangolo, P; Heredia-Guerrero, JA
Carbohydrate Polymers, 271 (2021) 118031
Materiales de Diseño para la Energía y Medioambiente


Cellulose ester films were prepared by esterification of cellulose with a multibranched fluorinated carboxylic acid, "BRFA" (BRanched Fluorinated Acid), at different anhydroglucose unit:BRFA molar ratios (i.e., 1:0, 10:1, 5:1, and 1:1). Morphological and optical analyses showed that cellulose-BRFA materials at molar ratios 10:1 and 5:1 formed flat and transparent films, while the one at 1:1 M ratio formed rough and translucent films. Degrees of substitution (DS) of 0.06, 0.09, and 0.23 were calculated by NMR for the samples at molar ratios 10:1, 5:1, and 1:1, respectively. ATR-FTIR spectroscopy confirmed the esterification. DSC thermograms showed a single glass transition, typical of amorphous polymers, at -11 degrees C. The presence of BRFA groups shifted the mechanical behavior from rigid to ductile and soft with increasing DS. Wettability was similar to standard fluoropolymers such as PTFE and PVDF. Finally, breathability and water uptake were characterized and found comparable to materials typically used in textiles.

Noviembre, 2021 | DOI: 10.1016/j.carbpol.2021.118031

Plasma-Assisted Deposition of TiO2 3D Nanomembranes: Selective Wetting, Superomniphobicity, and Self-Cleaning

Montes, L; Roman, JM; Garcia-Casas, X; Castillo-Seoane, J; Sanchez-Valencia, JR; Barranco, A; Lopez-Santos, C; Borras, A
Advanced Materials Interfaces (2021) 2100767
Nanotecnología en Superficies y Plasma


Fabrication of tunable wetting surfaces is sought for the last years given its importance on energy, biomaterials and antimicrobials, water purification, microfluidics, and smart surfaces. Liquid management on surfaces mainly depends on the control at the micro- and nanoscale of both roughness and chemical composition. Herein, the combination of a soft-template method and plasma-enhanced chemical vapor deposition is presented for the synthesis of TiO2 nanofibers on porous substrates such as cellulose and stainless-steel membranes. The protocol, carried out under mild conditions, produces 3D nanomembranes with superhydrophobicity and oleophilicity that are tested as microliter water/oil filters. Photoactivation of TiO2 by UV illumination provides a straightforward approach for wetting tunability that converts the surface into amphiphilic. A final chemical modification of the TiO2 nanofibers by embedding them in an elastomeric polymeric shell and by fluorine-based grafting opens the path toward the formation of superomniphobic and self-cleaning surfaces with long-lasting lifetimes. Thus, a reliable procedure is demonstrated for the fabrication of TiO2 nanofibers, which allows the modification of porous supports and provides an innovative route for the development of 3D nanomembranes with under design wetting. This protocol is extendable to alternative metal oxides, metals, and core@shell nanoarchitectures with potential multifunctionalities.

Octubre, 2021 | DOI: 10.1002/admi.202100767