Browsing by Autor "Carmen Guillem"

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    Enhanced manganese content in Mn-MCM-41 mesoporous silicas
    (Springer Science+Business Media, 2005) Jamal El Haskouri; Saúl Cabrera; Aurelio Beltrán; Carmen Guillem; D. Beltrán; J. Latorre; M. Dolores Marcos; Pedro Amorós
    The use of triethanolamine containing complexes of Si and Mn as hydrolytic precursors allows the synthesis of doped mesoporous silicas in which the Mn content can be modulated up to reach a minimum value of the Si/Mn molar ratio of 3. This limit value corresponds to a Mn relative content significantly higher than those reported to date for similar materials (Si/Mn = 6). According to XRD, TEM and porosity data, the mesoporous nature typical of the MCM-41 silicas is retained even for the samples having the highest Mn content.
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    One‐Pot Synthesis of Superparamagnetic CoO‐MCM‐41 Nanocomposites with Uniform and Highly Dispersed Magnetic Nanoclusters
    (Wiley, 2004) Jamal El Haskouri; Saúl Cabrera; Carmen Guillem; Julio Latorre; Aurelio Beltrán; M. Dolores Marcos; Carlos J. Gómez‐García; Daniel Beltrán; Pedro Amorós
    Abstract Superparamagnetic CoO‐MCM‐41 mesoporous nanocomposites, with variable cobalt amounts, in the form of well‐dispersed CoO‐like clusters, were prepared in a large compositional range by a one‐step reproducible procedure employing co‐hydrolysis and co‐condensation of the inorganic precursors in a water/triethanolamine medium. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
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    Ordered Mesoporous Silicon Oxynitrides
    (2001) Jamal El Haskouri; Saúl Cabrera; Fernando Sapiña; J. Latorre; Carmen Guillem; Aurelio Beltrán; Aurelio Beltrán; M. Dolores Marcos; Pedro Amorós
    The functionalization of mesostructured and/or mesoporous MCM-41 related silicas is easily achieved by treatment under NH3 atmosphere at relatively low temperatures without structural collapse. Nitridation, which occurs through a single-step solid-state reaction, yields for the first time ordered mesoporous silicon oxynitrides with high surface area (see Figure).