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Scientific Papers in SCI



2023


Fotocatálisis Heterogénea: Aplicaciones

Effect of phenol concentration on the photocatalytic performance of ZnO nanoparticles

Gonzalez, RL; De la Fuente, O; Garcia, RL; Lopez, MDU; Owen, PQ; Lopez, MCH; Lemus, MAA
Journal of Chemical Technology and Biotechnology, 98(8) (2023) 1826-1836

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BACKGROUND: Phenol and its derivatives are considered toxic compounds, even at low concentrations. Their accumulation in water effluents has become a serious problem that could be resolved by using zinc oxide (ZnO)-based photocatalysts.RESULTS: ZnO nanoparticles were synthesized through the precipitation method, using zinc nitrate and sodium carbonate as reagents. The as-synthesized powder was calcined for 4 h at 500 degrees C (2 degrees C min(-1)). X-Ray diffraction analysis confirmed a hexag-onal crystalline phase (wurtzite) with an average crystallite size of 38 nm. The Kubelka-Munk method was used to determine a band gap of 3.27 eV through UV-Vis diffuse reflectance spectrum and a Brunauer-Emmett-Teller (BET) specific area of 12 m(2) g(-1) was obtained from N2 adsorption analysis. The photocatalytic activity of ZnO was evaluated under visible light (300 W) lamp, with 1 mg mL(-1) of photocatalyst and using phenol solutions at different concentrations of 5,10, 25, and 50 ppm; the obtained degradation percentages were 98%, 97%, 94%, and 71%, respectively. Three cycles were performed with the ZnO used in the reactions with phenol at 5 and 50 ppm, decreasing the degraded percentages to 87% and 65%, respectively. The generation of hydroxyl radicals was estimated for the ZnO and ZnO samples after three cycles by means of fluorescence spectroscopy analy-sis. It was observed that the first-used ZnO material generated a significant amount of hydroxyl radicals.CONCLUSION: When compared to ZnO after three cycles of reaction, the amount of generated hydroxyl radicals decreased. It was observed that the higher the amount of phenol, the lower the generation of hydroxyl radicals after reuse; this was probably due to the presence of some adsorbed by-products of the photocatalytic reaction on the surface of ZnO, as the FTIR spectrum of the post-reaction sample showed.


February, 2023 | DOI: 10.1002/jctb.7334

Materiales de Diseño para la Energía y Medioambiente

Bio-based lacquers from industrially processed tomato pomace for sustainable metal food packaging

Benitez, JJ; Ramirez-Pozo, MC; Duran-Barrantes, MM; Heredia, A; Tedeschi, G; Ceseracciu, L; Guzman-Puyol, S; Marrero-López, D; Becci, A; Amato, A; Heredia-Guerrero, JA
Journal of Cleaner Production, 386 (2023) 1356836

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Bio-based lacquers prepared from an underutilized tomato processing residue such as pomace have been investigated as sustainable alternatives to bisphenol A (BPA)-based coatings for metal food packaging. The fabrication methodology consisted of a two-step process: spray-coating of a paste of the lipid fraction of tomato pomace with a mixture ethanol:H2O (3:1, v:v) on common metal substrates, used for food canning, such as aluminum (Al), chromium-coated tin-free steel (TFS), and electrochemically tin-plated steel (ETP), followed by the self melt-polycondensation of such lipid fraction. The polymerization reaction was conducted at 200 degrees C for different times (10, 20, 30, 40, 50, and 60 min) and was monitored by specular infrared spectroscopy, resulting in maximum degrees of esterification of-92% for Al and-85% for TFS and ETP substrates. The anticorrosion performance of the coatings was studied by electrochemical impedance spectroscopy at different immersion times (time intervals of 2-5 h during an overall stability test up to 170 h) in an aqueous solution of 1 wt% NaCl. The degree of polymerization and the physical properties of the coatings showed a strong dependence on the metal substrate used. In general, the best results were found for tomato pomace-based lacquers applied on aluminum, achieving higher mechanical strength (critical load of 1739 +/- 198 mN for Al, 1078 +/- 31 mN for ETP, and 852 +/- 206 mN for TFS), hydrophobicity (water contact angle-95 degrees for Al,-91 degrees for ETP, and-88 degrees for TFS), and improved anticorrosion performance (coating resistance of 0.7 M omega cm2 after 170 h of immersion for Al, 0.7 M omega cm2 after 70 h of immersion for TFS, and negligible coating resistance for ETP). In view of the technical innovation proposed in the present paper, the estimation of the environmental sustainability of the process has been considered relevant to fit the circular economy target. For this purpose, a life cycle analysis (LCA) was applied to the overall process, revealing multiple advantages for both the environment and human health.


February, 2023 | DOI: 10.1016/j.jclepro.2022.135836

Reactividad de Sólidos

Structural, Vibrational, and Magnetic Characterization of Orthoferrite LaFeO3 Ceramic Prepared by Reaction Flash Sintering

Manchon-Gordon, AF; Sanchez-Jimenez, PE; Blazquez, JS; Perejon, A; Perez-Maqueda, LA
Materials, 16 (2023) 1019

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LaFeO3 perovskite ceramics have been prepared via reaction flash technique using Fe2O3 and La2O3 as precursors. The obtained pellets have been investigated using several techniques. The formation of LaFeO3 has been clearly confirmed by X-ray diffraction. The scanning electron microscopy micrographs have shown the microporous character of the obtained pellets due to the low temperature and dwell time used in the synthesis process (10 min at 1173 K). The orthorhombic-rhombohedral phase transition has been observed at approximately 1273 K in differential thermal analysis measurements, which also allows us to determine the Neel temperature at 742 K. The fitted Mossbauer spectra exposed the presence of a single sextet ascribed to the Fe+3 ions in the tetrahedral site. Finally, magnetic measurements at room temperature indicate the antiferromagnetic character of the sample.


February, 2023 | DOI: 10.3390/ma16031019

Materiales Semiconductores para la Sostenibilidad

Non-sticky interactions

Esteso, V
Nature Physics, 19 (2023) 161-162

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Quantum mechanical fluctuations of the electromagnetic field in a vacuum between two close together objects result in an attractive force. Now, it has been experimentally shown that by exploiting a similar repulsive interaction, attraction between objects can be modulated simply by tuning temperature.


February, 2023 | DOI: 10.1038/s41567-022-01935-y

Nanotecnología en Superficies y Plasma

Photoelectrochemical Water Splitting with ITO/WO3/BiVO4/CoPi Multishell Nanotubes Enabled by a Vacuum and Plasma Soft- Template Synthesis

Gil-Rostra, J; Castillo-Seoane, J; Guo, Q; Sobrido, ABJ; Gonzalez-Elipe, AR; Borras, A
ACS Applied Materials & Interfaces, 15 (2023) 9250-9262

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A common approach for the photoelectrochemical (PEC) splitting of water relies on the application of WO3 porous electrodes sensitized with BiVO4 acting as a visible photoanode semiconductor. In this work, we propose a new architecture of photoelectrodes consisting of supported multishell nanotubes (NTs) fabricated by a soft-template approach. These NTs are formed by a concentric layered structure of indium tin oxide (ITO), WO3, and BiVO4, together with a final thin layer of cobalt phosphate (CoPi) co-catalyst. The photoelectrode manufacturing procedure is easily implementable at a large scale and successively combines the thermal evaporation of single crystalline organic nanowires (ONWs), the magnetron sputtering deposition of ITO and WO3, and the solution dripping and electrochemical deposition of, respectively, BiVO4 and CoPi, plus the annealing in air under mild conditions. The obtained NT electrodes depict a large electrochemically active surface and outperform the efficiency of equivalent planar-layered electrodes by more than one order of magnitude. A thorough electrochemical analysis of the electrodes illuminated with blue and solar lights demonstrates that the characteristics of the WO3/BiVO4 Schottky barrier heterojunction control the NT electrode efficiency, which depended on the BiVO4 outer layer thickness and the incorporation of the CoPi electrocatalyst. These results support the high potential of the proposed soft-template methodology for the large-area fabrication of highly efficient multishell ITO/WO3/BiVO4/CoPi NT electrodes for the PEC splitting of water.


February, 2023 | DOI: 10.1021/acsami.2c19868

 

 

 

 

 

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