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Digital.CSIC (162.855 recursos)

Repositorio institucional del Consejo Superior de Investigaciones Científicas. Digital.CSIC es un depósito de documentos digitales, cuyo objetivo es organizar, archivar, preservar y difundir en modo de acceso abierto la producción intelectual resultante de la actividad investigadora del CSIC.

(ICB) Artículos post-print

Mostrando recursos 1 - 20 de 136

  1. A novel approach to the chemical stabilization of gamma-irradiated ultrahigh molecular weight polyethylene using arc-discharge multi-walled carbon nanotubes

    Castell, Pere; Martínez-Morlanes, M. J.; Alonso, Pablo J.; Martínez Fernández de Landa, María Teresa; Puértolas, J. Antonio
    A complete study was made of the stabilization of gamma-irradiated ultrahigh molecular weight polyethylene (UHMWPE) using arc-discharge multi-walled carbon nanotubes (MWCNTs) as inhibitors of the oxidative process. MWCNTs were efficiently incorporated into the polymer matrix by ball milling and thermo-compression processes at concentrations up to 5 wt% and subsequently gamma irradiated at 90 kGy. Raman spectroscopy demonstrated the generation of radicals on the walls of the MWCNTs and that the G/D ratio was altered by their generation. The same spectra showed interactions between the polymer chains as a series of shifts are observed in the UHMWPE bands. The effect of...

  2. High surface - highly N-doped carbons from hydrothermally-treated tannin

    Braghiroli, Flavia L.; Fierro, Vanessa; Izquierdo Pantoja, María Teresa; Parmentier, Julien; Pizzi, Antonio; Delmotte, Luc; Fioux, Philippe; Celzard, Alain
    Nitrogen-doped carbon materials (NCMs) were obtained by amination of tannin by hydrothermal carbonisation (HTC). NCMs presented different morphologies depending on the amination method: (i) powders by HTC of tannin in a concentrated aqueous ammonia solution; (ii) gels without using any crosslinker by HTC in distilled water of tannin first dissolved in concentrated ammonia and then evaporated. Whatever the method, (i) or (ii), HTC was carried out at different temperatures: 180, 190, 200, 210 or 220°C, with further pyrolysis at 900°C under nitrogen. The morphology and chemical composition of the resultant materials were discussed. We compared our results with those reported in the open literature and we concluded...

  3. Evaluation of sol-gel TiO2 photocatalysts modified with carbon or boron compounds and crystallized in nitrogen or air atmospheres

    Ansón Casaos, Alejandro; Sampaio, Maria Jose; Jarauta-Córdoba, Clara; Martínez Fernández de Landa, María Teresa; Silva, Cláudia; Faria, Joaquim L.; Silva, Adrián
    Sol-gel TiO2 photocatalysts are synthesized from titanium isopropoxide and crystallized by thermal treatment under either air atmosphere or nitrogen flow. Reference TiO2 photocatalysts crystallized at 550 ºC for 30 min in air are the most active for the degradation of diphenhydramine pharmaceutical (DPH). In addition, TiO2 precursors are modified with carbon or boron compounds. The highest rates of conversion are obtained in the case of TiO2 modified with boric acid and crystallized in air. The sol-gel photocatalysts with the best performances possess anatase:rutile phase ratios in excess of 95% with anatase crystallites of approximately 60 nm. The photocatalysts are characterized...

  4. Electrical conductivity and tensile properties of block-copolymer-wrapped single-walled carbon nanotube / poly(methyl methacrylate) composites

    Ansón Casaos, Alejandro; Pascual, F. Javier; Ruano, Cristina; Fernández-Huerta, Natalia; Fernández-Pato, Isaías; Otero, Juan C.; Puértolas, J. Antonio; Martínez Fernández de Landa, María Teresa
    Poly(methyl methacrylate) (PMMA) composites containing raw or purified single-walled carbon nanotubes (SWCNTs) are prepared by in-situ polymerization and solution processing. The SWCNTs are purified by centrifugation in a Pluronic surfactant, which consists of polyethyleneoxide and polypropyleneoxide blocks. Both the effects of SWCNT purity and non-covalent functionalization with Pluronic are evaluated. Electrical conductivity of PMMA increases by 7 orders of magnitude upon the integration of raw or purified SWCNTs. The best electrical properties are measured for composites made of purified SWCNTs and prepared by in-situ polymerization. Strains at fracture of the SWCNT/PMMA composites are nearly identical to those of the neat...

  5. Effect of the synthesis conditions of Ni/Al2O3 catalysts on the biogas decomposition to produce H2-rich gas and carbon nanofibers

    Llobet, Saúl de; Pinilla Ibarz, José Luis; Moliner Álvarez, Rafael; Suelves Laiglesia, Isabel
    © 2014 Elsevier B.V. The utilization of biogas as carbon source for the co-production of filamentous-like materials and syngas is proposed. Catalysts with different Ni:Al molar ratios, Al2O3 supports and preparation methods were synthesized. The suitability of the catalysts was analyzed considering activity, stability and carbon yield. Catalysts showed a good performance and similar results according to syngas compositions were obtained. However, some differences related to stability over time and carbon yields were detected. TPR analysis and TEM micrographs of the fresh catalysts revealed the presence of two different Ni particles: large Ni particles with low metal support interaction (MSI)...

  6. Integration and bioactivity of hydroxyapatite grown on carbon nanotubes and graphene oxide

    Núñez, Jesús David; Benito, Ana M.; González García, Ramón; Aragón, Javier; Arenal, Raúl; Maser, Wolfgang K.
    We report on the growth of non-stoichiometric nanocrystalline hydroxyapatite (nHAp) with a composition similar to natural bone by a wet-chemical in-situ precipitation route on carbon nanotubes (CNTs) with different degrees of oxygen functionalities and on graphene oxide (GO). Both, functionalization degree and morphology of CNTs and GO appear as critical parameters controlling the shape and crystallinity of the self-assembled nHAp nanoparticles in the corresponding composite materials. Crystalline nHAp nanoparticles with rod-like morphology were achieved for moderately oxidized CNTs and for GO. On CNTs these grow along the CNT’s axis while on GO they form a compact layer. In both cases enhanced nHAp integration onto the respective carbon support...

  7. Relationship between carbon morphology and catalyst deactivation in the catalytic decomposition of biogas using Ni, Co and Fe based catalysts

    Llobet, Saúl de; Pinilla Ibarz, José Luis; Moliner Álvarez, Rafael; Suelves Laiglesia, Isabel
    7 pages, 2 tables, 6 figures.--Accepted 13 August 2014

  8. The fate of sulphur in the Cu-based Chemical Looping with Oxygen Uncoupling (CLOU) Process

    Adánez-Rubio, Iñaki; Abad Secades, Alberto; Gayán Sanz, Pilar; García Labiano, Francisco; Diego Poza, Luis F. de; Adánez Elorza, Juan
    8 pages, 2 figures, 2 tbles.-Available online 3 July 2013

  9. Biomass combustion with CO2 capture by chemical looping with oxygen uncoupling (CLOU)

    Adánez-Rubio, Iñaki; Abad Secades, Alberto; Gayán Sanz, Pilar; Diego Poza, Luis F. de; García Labiano, Francisco; Adánez Elorza, Juan
    10 pages, 8 figures, 2 tables.- Available online 17 March 2014

  10. Co-pyrolysis of biomass with waste tyres: Upgrading of liquid bio-fuel

    Martínez Angel, Juan Daniel; Veses Roda, Alberto; Mastral Lamarca, Ana María; Murillo Villuendas, Ramón; Navarro López, María Victoria; Puy Marimon, Neus; Artigues Anna; Bartrolí Molins, Jordi; García Martínez, Tomás
    9 pages, 6 figures, 3 tables.--Available online 8 December 2013

  11. Effect of operating conditions and H2S presence on the performance of CaMg0.1Mn0.9O3-δ perovskite material in chemical looping combustion (CLC)

    Cabello Flores, Arturo; Abad Secades, Alberto; Gayán Sanz, Pilar; Diego Poza, Luis F. de; García Labiano, Francisco; Adánez Elorza, Juan
    13 pages, 13 figures, 3 tables.--Published January 27, 2014

  12. Influence of the surface potassium species in Fe-K/Al2O3 catalysts on the soot oxidation activity in the presence of NOx

    Gálvez Parruca, María Elena; Ascaso Malo, Sonia; Stelmachowski, P.; Legutko, P.; Kotarba, A.; Moliner Álvarez, Rafael; Lázaro Elorri, María Jesús
    11 pag., 15 figures, 4 tables.--Available online 27 January 2013

  13. Relevance of the catalytic activity on the performance of a NiO/CaAl2O4 oxygen carrier in a CLC process

    Cabello Flores, Arturo; Gayán Sanz, Pilar; García Labiano, Francisco; García Labiano, Francisco; Diego Poza, Luis F. de; Abad Secades, Alberto; Izquierdo Pantoja, María Teresa; Adánez Elorza, Juan
    8 pages, 7 figures, 5 tables.--Available online 24 October 2013.--This is an open-access article distributed under the terms of the CreativeCommons Attribution License, which permits unrestricted use, distribution, andreproduction in any medium, provided the original author and source are credited.∗

  14. Performance of a highly reactive impregnated Fe2O 3/Al2O3 oxygen carrier with CH4 and H2S in a 500 Wth CLC unit

    Cabello Flores, Arturo; Dueso, Cristina; García Labiano, Francisco; García Labiano, Francisco; Gayán Sanz, Pilar; Abad Secades, Alberto; Diego Poza, Luis F. de; Adánez Elorza, Juan
    A synthetic Fe-based oxygen carrier prepared by impregnation using γ-Al2O3 as support, successfully tested for gas CLC combustion, has been now evaluated with respect to gas combustion in a 500 Wth CLC continuous unit when the fuel, CH4, contained variable amounts of H2S. Full gas combustion was reached at oxygen carrier-to-fuel ratio values higher than 1.5. The presence of sulfur in the fuel gas hardly affected the reactivity and combustion efficiency of the oxygen carrier, independently of the amount of sulfur in the gas stream. All the sulfur introduced as H2S in the fuel reactor (FR) was released in the...

  15. Release of pollutant components in CLC of lignite

    Mendiara, Teresa; Izquierdo Pantoja, María Teresa; Abad Secades, Alberto; Diego Poza, Luis F. de; García Labiano, Francisco; Gayán Sanz, Pilar; Adánez Elorza, Juan
    The recently developed Chemical Looping Combustion technology (CLC) is nowadays considered an interesting option to capture CO2 at low cost in fossil fuelled power plants. In the past years, significant advances have been achieved in the combustion of both gaseous and solid fuels. Nevertheless, pollutant gas emissions from CLC systems have received little attention. This paper focuses on sulphur, nitrogen and mercury emissions during lignite combustion in a 500Wth CLC unit. Ilmenite was used as oxygen carrier, as it is one of the most common materials used for CLC of solid fuels. The main sulphur species detected in the fuel...

  16. On the use of a highly reactive iron ore in chemical looping combustion of different coals

    Mendiara, Teresa; Diego Poza, Luis F. de; García Labiano, Francisco; Gayán Sanz, Pilar; Abad Secades, Alberto; Adánez Elorza, Juan
    10 páginas, 12 figuras, 3 tablas.--Available online 11 March 2014

  17. Effect of carbon nanotube type and functionalization on the electrical, thermal, mechanical and electromechanical properties of carbon nanotube/styrene-butadiene-styrene composites for large strain sensor applications

    Costa, Pedro; Silva, J.; Ansón Casaos, Alejandro; Martínez Fernández de Landa, María Teresa; Abad, María José; Viana, J.; Lanceros-Méndez, Senentxu
    Thermoplastic elastomer tri-block copolymer, namely styrene-butadiene- styrene (SBS) composites filled with carbon nanotubes (CNT) are characterized with the main goal of obtaining electro-mechanical composites suitable for large deformation sensor applications. CNT/SBS composites with different filler contents and filler functionalizations are studied by morphological, thermal, mechanical and electrical analyses. It is shown that the different dispersion levels of CNT in the SBS matrix are achieved for pristine or functionalized CNT with strong influence in the electrical properties of the composites. In particular covalently functionalized CNTs show percolation thresholds higher than 8 weight percentage (wt%) whereas pristine CNT show percolation threshold smaller...

  18. The effect of gamma irradiation on few layered graphene materials

    Ansón Casaos, Alejandro; Puértolas, J. Antonio; Pascual, F. Javier; Hernández-Ferrer, Javier; Castell, Pere; Benito, Ana M.; Maser, Wolfgang K.; Martínez Fernández de Landa, María Teresa
    9 pages, 9 figures.-- Available online 21 February 2014

  19. Gold/carbon nanocomposite foam

    Muñoz, Edgar; Val, Marta de; Ruíz-González, M. L.; López-Gascón, Clarisa; Sanjuán, M. L.; Martínez Fernández de Landa, María Teresa; González-Calbet, José M.; Fuente, Germán F. de la; Laguna, Mariano
    4 pages, 5 figures.

  20. Tailored synthesis of organised mesoporous aluminas prepared by non-ionic surfactant templating using a Box-Wilson CCF design

    Llobet, Saúl de; Purón, Holda; Pinilla Ibarz, José Luis; Moliner Álvarez, Rafael; Millán, Marcos; Suelves Laiglesia, Isabel
    9 pages, 7 figures, 4 tables.--Available online 23 May 2013

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