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Artículos SCI



2008


Química de Superficies y Catálisis

Photocatalytic Degradation of 2,4-Dichlorophenoxyacetic Acid Over ZrO2, Cu/ZrO2 and Fe/ZrO2 Photocatalysts Synthesized by Sol Gel Method

Alvarez, M; Lopez, T; Odriozola, JA; Gonzalez, RD
Journal of Nanoscience and Nanotechnology, 8 (2008) 6414-6418

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Photocatalytic oxidation of 2,4-dichlorophenoxyacetic acid was performed over ZrO2, Cu/ZrO2 and Fe/ZrO2 catalysts prepared by the sol-gel method. The samples were annealed at 400 degrees C. Textural and electronic characterization was carried out using BET and UV-Vis in order to establish the relationship between surface, pore volume and E. with the photoactivity of the materials. The degradation of the acid was followed by UV-Vis spectroscopy. The disappearance of the herbicide in solution follows approximately pseudo-first order kinetics. The apparent rate constants were calculated for the three catalysts. The results reveal that Fe/ZrO2 exhibits the best photoactivity for the degradation of 2,4-dichlorophenoxyacetic acid.


Diciembre, 2008 | DOI: 10.1166/jnn.2008.003

Materiales de Diseño para la Energía y Medioambiente

Fabrication, chemical etching, and compressive strength of porous biomimetic SiC for medical implants

Torres-Raya, C; Hernandez-Maldonado, D; Ramirez-Rico, J; Garcia-Ganan, C; de Arellano-Lopez, AR; Martinez-Fernandez, J
Journal of Materials Research, 23 (2008) 3247-3254

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BioSiC is a biomimetic SiC-based ceramic material fabricated by Si melt infiltration of carbon preforms obtained from wood. The microstructure of bioSiC mimics that of the wood precursor. which can be chosen for tailored properties. When the remaining g unreacted Si is removed. a SiC Material with interconnected porosity is obtained. This porous bioSiC is Under study for its use as a medical Implant material. We have successfully fabricated bioSiC from Sipo wood and Studied the kinetics of Si removal by wet etching. The results suggest that the reaction is diffusion-limited, and the etch rate follows a t(-0.5) law. The etching rate is found to be anisotropic, which can be explained attending to the anisotropy of the pore distribution. The compressive strength was studied as a function of etching, time. and the results show a quadratic dependence with density. In the attainable ran-e of densities, the strength is similar or better than that of human bone.


Diciembre, 2008 | DOI: 10.1557/JMR.2008.0392

Nanotecnología en Superficies y Plasma

Growth and characterization of the ZnO/ZnS bilayer obtained by chemical spray pyrolysis

Lopez, MC; Espinos, JP; Leinen, D; Martin, F; Centeno, SP; Romero, R; Ramos-Barrado, JR
Applied Surface Science, 255 (2008) 2118-2124

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ZnO/ZnS bilayer antireflection coatings have been prepared by spray pyrolysis using aqueous solutions of zinc acetate and thiourea or zinc chloride and thiourea. The structure, surface morphology, chemical composition and optical transmittance of the bilayer have been examined as a function of the composition of the initial solution. X-ray photoelectron spectroscopy analysis and Ar ion-beam sputter etching was carried out to obtain a depth profile of bilayer. Neither carbon nor other by-products, which could alter the optical transmittance of the bilayer were found in either the interface or bulk. The differences between the bilayers arise from the annealing of the ZnS underlayer, as well as the precursor used to prepare it.


Diciembre, 2008 | DOI: 10.1016/j.apsusc.2008.06.195

Nanotecnología en Superficies y Plasma

Synthesis of Supported Single-Crystalline Organic Nanowires by Physical Vapor Deposition

Borras, A; Aguirre, M; Groening, O; Lopez-Cartes, C; Groening, P
Chemistry of Materials, 20 (2008) 7371-7373

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Characterization of iron oxide-based pigments by synchrotron-based micro X-ray diffraction

Herrera, LK; Cotte, M; de Haro, MCJ; Duran, A; Justo, A; Perez-Rodriguez, JL
Applied Clay Science, 42 (2008) 57-62

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The characterization of iron in microsamples by conventional X-ray diffraction is difficult due to its low concentration in thin layers and its low reflecting power relative to other phases. Synchrotron radiation can provide unique information because of high intensity, sample penetration, small beam diameter and fast data collection. In this study, micro X-ray diffraction (mu-XRD) data were obtained of two samples taken from wall paintings at San Agustin's Church in Cordoba. Crystalline iron phases such as goethite, lepidocrocite and hematite in the cross-section of the painting thin layers were identified. with a good spatial resolution. Conventional XRD only detected hydrocerussite and cerussite rather than the full range of iron phases found in the mu-XRD experiments. 


Diciembre, 2008 | DOI: 10.1016/j.clay.2008.01.021

 

 

 

 

 

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