J. Ramírez-castellanos | Universidad Complutense de Madrid (original) (raw)
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Papers by J. Ramírez-castellanos
Proceedings of Gubkin Russian State University of Oil and Gas, 2020
Annales de Chimie Science des Matériaux, 2003
Journal of Materials Chemistry C, 2020
Herein, we achieve the synthesis and structural study of a luminescent Na-stabilized Ga–Ti oxide ... more Herein, we achieve the synthesis and structural study of a luminescent Na-stabilized Ga–Ti oxide homologous series by atomically resolved electron microscopy.
In this work poly(3, 4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) dispersed in so... more In this work poly(3, 4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) dispersed in solvent (5wt.% Dimethyl sulfoxide DMSO & 0.1wt.% Triton X-100) has been studied in pure form and when functionallized with SnO nanoparticles. A preliminary characterization of bare PEDOT:PSS and romarchite SnO nanoparticles synthesized by hydrolysis were firstly carried out. PEDOT:PSS was deposited on FZ n-Si by spin coating method. The influence of a piranha pre-treatment on the Si surface has been evaluated in this work, as well as the effects due to the presence of SnO nanoparticles in the polymer. After achieving good adhesion and passivation of Si surface, the heterostructure has been characterized systematically by means of Raman spectroscopy using a He-Cd (l = 325 nm) laser as excitation source, atomic force microscopy (AFM), scanning electron microscopy (SEM) and photoluminescence (PL) spectra, and PL image. Spatial homogeneity of the film composition on surface has been achieved. ...
J. Mater. Chem. C, 2017
Several terms of the homologous series ZnkIn2Ok+3 (3 ≤ k ≤ 13) have been synthesized following so... more Several terms of the homologous series ZnkIn2Ok+3 (3 ≤ k ≤ 13) have been synthesized following solid-state reactions with an exhaustive control of the synthesis parameters. A detailed study by...
EMC 2008 14th European Microscopy Congress 1–5 September 2008, Aachen, Germany
The artistic presence of Rubens in Spain is notable and the National Museum of the Prado has an i... more The artistic presence of Rubens in Spain is notable and the National Museum of the Prado has an important number of works his. Some of them were made in Spain during their two stays in the Royal court; others come from Ambers (Belgium), where he used to work usually. The peculiar characteristics in the painting method that he used may
Microporous and Mesoporous Materials, 2004
Porous materials were obtained from clays by gallery templated synthesis. The equivalent surface ... more Porous materials were obtained from clays by gallery templated synthesis. The equivalent surface areas of the samples were in the range 600-700 m 2 g À1 and the corresponding microporous volumes were near 0.3 cm 3 g À1. HRTEM confirmed the lack of longrange order of the prepared samples. Low temperature nitrogen adsorption showed textural differences in the samples, namely those arising from the neutral amines of different chain length used in synthesis. The possibility of using such materials as adsorbents of volatile organic compounds, due to their textural and hydrophobic characteristics, was studied by the adsorption of ethanol and methyl ethyl ketone and water for comparison. Their potential use as adsorbents for the purification of methane, e.g., for upgrading natural or landfill gas, was also studied by the determination of the room temperature adsorption isotherms of carbon dioxide, ethane, methane and nitrogen, where high initial selectivity values were obtained for the methane/carbon dioxide separation.
Journal of Solid State Chemistry, 2000
European Journal of Inorganic Chemistry, 2007
En este trabajo se han caracterizado la microestructura y las propiedades mecánicas alrededor de ... more En este trabajo se han caracterizado la microestructura y las propiedades mecánicas alrededor de la intercara de un material multicapa de aluminio basado en las aleaciones Al 7075 y Al 2024. Las técnicas empleadas, principalmente, han sido EBSD y ensayos de cizalla para determinar propiedades mecánicas de las intercaras, en función del tiempo de solubilización durante el tratamiento térmico T6. Dicho tratamiento modifica la microestructura de las aleaciones constituyentes adyacentes a la intercara y, por tanto, las propiedades mecánicas de esta. La combinación de la ruta de procesado adecuada mediante laminación en caliente, junto con un tratamiento térmico optimizado conduce a intercaras resistentes, propensas a delaminar y, por ello, a materiales con propiedades mecánicas excelentes.
Chemistry of Materials, 2010
Chemical Communications, 2011
CrystEngComm, 2014
SnO 2 nanoparticles doped with transition metals (V, Cr, Mn) have been synthesized by both the hy... more SnO 2 nanoparticles doped with transition metals (V, Cr, Mn) have been synthesized by both the hydrothermal method (HDT) in a basic media and the liquid mixed method (LQM) based on the Pechini method. Nanocrystalline particles obtained via a liquid mixed technique show a well-defined chemical composition and an average size of 6 nm, with a high degree of both crystallinity and chemical homogeneity. Nanoparticles prepared via a hydrothermal method exhibit a high dispersion in size as well as agglomeration effects. As the LQM demonstrates advantages with respect to the HDT, a more detailed investigation has been carried out on the SnO 2 nanoparticles doped with V, Cr and Mn grown by this method. The microstructure of the materials was elucidated by means of X-ray Diffraction (XRD), Selected-Area Electron Diffraction (SAED), and High-Resolution Transmission Electron Microscopy (HRTEM). Luminescence from undoped and doped SnO 2 nanoparticles was characterized by cathodoluminescence (CL). The luminescence studies demonstrate a strong dependence of CL signals with transition metal doping, thus inducing red, green or orange emissions when doping with Cr, V or Mn respectively.
The use of NiO in low-dimensional devices requires appropriate synthesis methods allowing to cont... more The use of NiO in low-dimensional devices requires appropriate synthesis methods allowing to control the morphology, size, and final composition of the as-grown samples in order to improve and broaden the applicability of this material in different fields of research. In this work, a vapor-solid and a hydrothermal method have been employed and evaluated for the fabrication of undoped and Sn doped NiO micro and nanostructures. The presence of Sn favours the growth of microwires, by means of thermal treatments at 1400 °C, while by using a hydrothermal process nanobars and nanoparticles with reduced dimensions were obtained. The chemical method leads to a higher control in the final concentration of Sn incorporated in the NiO lattice. X-ray diffraction confirms the crystalline quality of the obtained products, as well as a texture effects and peak-shift associated with the Sn doping process. Photoluminescence measurements demonstrate an increase in the luminescent signal promoted by Sn...
Revista Mexicana de Ingeniería Química
This work has to purpose decrease the value of the cell potential (Ecell) of an electrochemical r... more This work has to purpose decrease the value of the cell potential (Ecell) of an electrochemical reactor with a separate compartment with an anionic membrane designed for electro-leaching electronic waste (E-waste). In the anodic compartment using a titanium plate in HNO3 as an anolyte, while the electro-leaching of the metals and the evaluation of the oxygen evolution reaction (OER) was studied. Three different cathodes (Platinum; Pt, titanium coated with ruthenium oxide; RuO2|Ti and titanium coated with platinum nanoparticles; nPt/C|Ti) were used for the catalysis of the evolution reaction of hydrogen (HER) in a solution of H2SO4. The results obtained by voltammetry indicate that the electrodes modified with RuO2 and nPt/C, promote a greater cathodic current for the HER, decreasing the cell potential and increase the current density of the induced metallic electro-leaching. This implies the decrease of the electrical power that the reactor requires during its operation. Obtaining Space-time yield (STY) values of 123.4 and 64 mol·L-1·h-1·cm-2 for the carbon and platinum nanoparticle and the ruthenium oxide catalysts respectively.
PÄDI Boletín Científico de Ciencias Básicas e Ingenierías del ICBI, Jan 5, 2018
los fenómenos de adsorción (fisisorción y quimisorción) son de gran utilidad en la caracterizació... more los fenómenos de adsorción (fisisorción y quimisorción) son de gran utilidad en la caracterización de superficies, algunos ejemplos de ello son: la determinación del área superficial usando el método BET, determinación de sitios ácidos o básicos usando la técnica de desorción a temperatura programada o TPD por sus siglas en inglés (Temperature Programmed Desorption), determinación de tamaño y dispersión de partículas metálicas por TPD, por mencionar algunas aplicaciones. En la presente practica se reporta el uso de la técnica de TPD mediante el cual se ha determinado la dispersión y el tamaño promedio de partículas metálicas de Pt dispersas sobre un soporte de ZnO, esto con la finalidad de conocer la distribución promedio de dichas partículas, debido a que su contenido en peso sobre el soporte es muy bajo, por lo cual no se ha podido determinar usando otras técnicas como MEB o DRX. La técnica de TPD resulta una gran alternativa para estos fines.
CrystEngComm
Different Mo oxides obtained on desired locations by laser irradiation of h-MoO3 microrods, as mo... more Different Mo oxides obtained on desired locations by laser irradiation of h-MoO3 microrods, as monitored by micro-Raman and photoluminescence spectroscopy.
Proceedings of Gubkin Russian State University of Oil and Gas, 2020
Annales de Chimie Science des Matériaux, 2003
Journal of Materials Chemistry C, 2020
Herein, we achieve the synthesis and structural study of a luminescent Na-stabilized Ga–Ti oxide ... more Herein, we achieve the synthesis and structural study of a luminescent Na-stabilized Ga–Ti oxide homologous series by atomically resolved electron microscopy.
In this work poly(3, 4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) dispersed in so... more In this work poly(3, 4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) dispersed in solvent (5wt.% Dimethyl sulfoxide DMSO & 0.1wt.% Triton X-100) has been studied in pure form and when functionallized with SnO nanoparticles. A preliminary characterization of bare PEDOT:PSS and romarchite SnO nanoparticles synthesized by hydrolysis were firstly carried out. PEDOT:PSS was deposited on FZ n-Si by spin coating method. The influence of a piranha pre-treatment on the Si surface has been evaluated in this work, as well as the effects due to the presence of SnO nanoparticles in the polymer. After achieving good adhesion and passivation of Si surface, the heterostructure has been characterized systematically by means of Raman spectroscopy using a He-Cd (l = 325 nm) laser as excitation source, atomic force microscopy (AFM), scanning electron microscopy (SEM) and photoluminescence (PL) spectra, and PL image. Spatial homogeneity of the film composition on surface has been achieved. ...
J. Mater. Chem. C, 2017
Several terms of the homologous series ZnkIn2Ok+3 (3 ≤ k ≤ 13) have been synthesized following so... more Several terms of the homologous series ZnkIn2Ok+3 (3 ≤ k ≤ 13) have been synthesized following solid-state reactions with an exhaustive control of the synthesis parameters. A detailed study by...
EMC 2008 14th European Microscopy Congress 1–5 September 2008, Aachen, Germany
The artistic presence of Rubens in Spain is notable and the National Museum of the Prado has an i... more The artistic presence of Rubens in Spain is notable and the National Museum of the Prado has an important number of works his. Some of them were made in Spain during their two stays in the Royal court; others come from Ambers (Belgium), where he used to work usually. The peculiar characteristics in the painting method that he used may
Microporous and Mesoporous Materials, 2004
Porous materials were obtained from clays by gallery templated synthesis. The equivalent surface ... more Porous materials were obtained from clays by gallery templated synthesis. The equivalent surface areas of the samples were in the range 600-700 m 2 g À1 and the corresponding microporous volumes were near 0.3 cm 3 g À1. HRTEM confirmed the lack of longrange order of the prepared samples. Low temperature nitrogen adsorption showed textural differences in the samples, namely those arising from the neutral amines of different chain length used in synthesis. The possibility of using such materials as adsorbents of volatile organic compounds, due to their textural and hydrophobic characteristics, was studied by the adsorption of ethanol and methyl ethyl ketone and water for comparison. Their potential use as adsorbents for the purification of methane, e.g., for upgrading natural or landfill gas, was also studied by the determination of the room temperature adsorption isotherms of carbon dioxide, ethane, methane and nitrogen, where high initial selectivity values were obtained for the methane/carbon dioxide separation.
Journal of Solid State Chemistry, 2000
European Journal of Inorganic Chemistry, 2007
En este trabajo se han caracterizado la microestructura y las propiedades mecánicas alrededor de ... more En este trabajo se han caracterizado la microestructura y las propiedades mecánicas alrededor de la intercara de un material multicapa de aluminio basado en las aleaciones Al 7075 y Al 2024. Las técnicas empleadas, principalmente, han sido EBSD y ensayos de cizalla para determinar propiedades mecánicas de las intercaras, en función del tiempo de solubilización durante el tratamiento térmico T6. Dicho tratamiento modifica la microestructura de las aleaciones constituyentes adyacentes a la intercara y, por tanto, las propiedades mecánicas de esta. La combinación de la ruta de procesado adecuada mediante laminación en caliente, junto con un tratamiento térmico optimizado conduce a intercaras resistentes, propensas a delaminar y, por ello, a materiales con propiedades mecánicas excelentes.
Chemistry of Materials, 2010
Chemical Communications, 2011
CrystEngComm, 2014
SnO 2 nanoparticles doped with transition metals (V, Cr, Mn) have been synthesized by both the hy... more SnO 2 nanoparticles doped with transition metals (V, Cr, Mn) have been synthesized by both the hydrothermal method (HDT) in a basic media and the liquid mixed method (LQM) based on the Pechini method. Nanocrystalline particles obtained via a liquid mixed technique show a well-defined chemical composition and an average size of 6 nm, with a high degree of both crystallinity and chemical homogeneity. Nanoparticles prepared via a hydrothermal method exhibit a high dispersion in size as well as agglomeration effects. As the LQM demonstrates advantages with respect to the HDT, a more detailed investigation has been carried out on the SnO 2 nanoparticles doped with V, Cr and Mn grown by this method. The microstructure of the materials was elucidated by means of X-ray Diffraction (XRD), Selected-Area Electron Diffraction (SAED), and High-Resolution Transmission Electron Microscopy (HRTEM). Luminescence from undoped and doped SnO 2 nanoparticles was characterized by cathodoluminescence (CL). The luminescence studies demonstrate a strong dependence of CL signals with transition metal doping, thus inducing red, green or orange emissions when doping with Cr, V or Mn respectively.
The use of NiO in low-dimensional devices requires appropriate synthesis methods allowing to cont... more The use of NiO in low-dimensional devices requires appropriate synthesis methods allowing to control the morphology, size, and final composition of the as-grown samples in order to improve and broaden the applicability of this material in different fields of research. In this work, a vapor-solid and a hydrothermal method have been employed and evaluated for the fabrication of undoped and Sn doped NiO micro and nanostructures. The presence of Sn favours the growth of microwires, by means of thermal treatments at 1400 °C, while by using a hydrothermal process nanobars and nanoparticles with reduced dimensions were obtained. The chemical method leads to a higher control in the final concentration of Sn incorporated in the NiO lattice. X-ray diffraction confirms the crystalline quality of the obtained products, as well as a texture effects and peak-shift associated with the Sn doping process. Photoluminescence measurements demonstrate an increase in the luminescent signal promoted by Sn...
Revista Mexicana de Ingeniería Química
This work has to purpose decrease the value of the cell potential (Ecell) of an electrochemical r... more This work has to purpose decrease the value of the cell potential (Ecell) of an electrochemical reactor with a separate compartment with an anionic membrane designed for electro-leaching electronic waste (E-waste). In the anodic compartment using a titanium plate in HNO3 as an anolyte, while the electro-leaching of the metals and the evaluation of the oxygen evolution reaction (OER) was studied. Three different cathodes (Platinum; Pt, titanium coated with ruthenium oxide; RuO2|Ti and titanium coated with platinum nanoparticles; nPt/C|Ti) were used for the catalysis of the evolution reaction of hydrogen (HER) in a solution of H2SO4. The results obtained by voltammetry indicate that the electrodes modified with RuO2 and nPt/C, promote a greater cathodic current for the HER, decreasing the cell potential and increase the current density of the induced metallic electro-leaching. This implies the decrease of the electrical power that the reactor requires during its operation. Obtaining Space-time yield (STY) values of 123.4 and 64 mol·L-1·h-1·cm-2 for the carbon and platinum nanoparticle and the ruthenium oxide catalysts respectively.
PÄDI Boletín Científico de Ciencias Básicas e Ingenierías del ICBI, Jan 5, 2018
los fenómenos de adsorción (fisisorción y quimisorción) son de gran utilidad en la caracterizació... more los fenómenos de adsorción (fisisorción y quimisorción) son de gran utilidad en la caracterización de superficies, algunos ejemplos de ello son: la determinación del área superficial usando el método BET, determinación de sitios ácidos o básicos usando la técnica de desorción a temperatura programada o TPD por sus siglas en inglés (Temperature Programmed Desorption), determinación de tamaño y dispersión de partículas metálicas por TPD, por mencionar algunas aplicaciones. En la presente practica se reporta el uso de la técnica de TPD mediante el cual se ha determinado la dispersión y el tamaño promedio de partículas metálicas de Pt dispersas sobre un soporte de ZnO, esto con la finalidad de conocer la distribución promedio de dichas partículas, debido a que su contenido en peso sobre el soporte es muy bajo, por lo cual no se ha podido determinar usando otras técnicas como MEB o DRX. La técnica de TPD resulta una gran alternativa para estos fines.
CrystEngComm
Different Mo oxides obtained on desired locations by laser irradiation of h-MoO3 microrods, as mo... more Different Mo oxides obtained on desired locations by laser irradiation of h-MoO3 microrods, as monitored by micro-Raman and photoluminescence spectroscopy.