A5013130611- Iron oxide chemistry and applications
- Magnetic Properties and Synthesis of Ferrites
- Magnetic properties of thin films
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Electrochemical Analysis and Applications
- Electrocatalysts for Energy Conversion
- Crystal Structures and Properties
- Metal and Thin Film Mechanics
- Multiferroics and related materials
- Corrosion Behavior and Inhibition
- Nuclear materials and radiation effects
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
- Diamond and Carbon-based Materials Research
- Porphyrin and Phthalocyanine Chemistry
- Advancements in Battery Materials
- Electrochemical sensors and biosensors
- Electronic and Structural Properties of Oxides
- Catalytic Processes in Materials Science
- Magnetic Properties and Applications
- Ion-surface interactions and analysis
- Characterization and Applications of Magnetic Nanoparticles
- Theoretical and Computational Physics
- Advancements in Solid Oxide Fuel Cells
Instituto de Química Física Blas Cabrera
2015-2024
Consejo Superior de Investigaciones Científicas
2011-2024
Instituto de Astrofísica de Canarias
2024
Instituto de Química y Fisicoquímica Biológicas
2023
Catalytic Materials (United States)
2022
University of Birmingham
1991-2019
Instituto de España
2019
Unidades Centrales Científico-Técnicas
2004-2017
Universidad Politécnica de Madrid
2017
Universidad de Santiago de Chile
2007-2010
Magnetite nanoparticles with two different sizes, 5 and 17 nm, have been prepared by the decomposition of organic precursors in an media presence oleic acid. The particles were characterized TEM, X-ray diffraction, IR Mössbauer spectroscopy to clarify their structural physicochemical properties. samples consist noninteracting magnetite both cases a more uniform size distribution higher crystal order degree than similar sizes coprecipitation. A controlled heat treatment air leads...
O3-type layered oxide materials are considered to be a highly suitable cathode for sodium-ion batteries (NIBs) due their appreciable specific capacity and energy density. However, rapid fading caused by serious structural changes interfacial degradation hampers use. A novel Sn-modified NaNi1/3Fe1/3Mn1/3O2 is presented, with improved high-voltage stability through simultaneous bulk Sn doping surface coating in scalable one-step process. The substitution of Sn4+ stabilizes the crystal...
The compound NiCo2O4, with spinel-related structure, has been prepared by thermal decomposition of metal nitrates and its bulk structural properties examined means magnetic measurements, neutron diffraction, X-ray absorption near edge structure (XANES) extended fine (EXAFS). results suggest a delocalised electron distribution on the octahedral sites average oxidation states +3.5 +2.5 for nickel cobalt, respectively, lead to cation NiCo2O4 {Ni3+0.1Co2+0.9}tet[Ni3.5+0.9Co2.5+1.1]octO4. This...
A direct method for the preparation of uniform magnetite nanoparticles with sizes around 30 nm and stable in aqueous media at pH 7 has been developed. This is based on precipitation an iron (II) salt (FeSO4) presence a base (NaOH) mild oxidant (KNO3). Reaction rate seems to be controlled by concentration ethanol media. Thus lower water/ethanol ratio equal one lead formation smallest particles, diameter. Colloidal suspensions these particles were directly obtained simple ultrasonic treatment...
A considerable increase in the saturation magnetization, M(s) (40%), and initial susceptibility of ultrasmall (<5 nm) iron oxide nanoparticles prepared by laser pyrolysis was obtained through an optimized acid treatment. Moreover, a significant enhancement colloidal properties, such as smaller aggregate sizes aqueous media increased surface charge densities, found after this chemical protocol. The results are consistent with reduction nanoparticle disorder induced...
An efficient and inexpensive catalyst for the oxygen reduction reaction (ORR) is key missing component large-scale development of fuel cells.
The oldest known magnetic material, magnetite, is of current interest for use in spintronics as a thin film. An open question how can magnetite films be and still retain the robust ferrimagnetism required many applications. We have grown 1-nm-thick crystals characterized them situ by electron photoelectron microscopies including selected-area x-ray circular dichroism. Well-defined patterns are observed individual nanocrystals up to at least 520 K, establishing retention two unit cells thick.
The study of non-precious metal catalysts (NPMCs) as alternatives to platinum for oxygen reduction is crucial if the use fuel cells become more widespread. Among NPMCs, pyrolyzed (Fe-N-C) are particularly promising in both basic and acid media. characterization active sites understanding reaction (ORR) mechanism design Fe-N-C catalysts. In this study, we have tested involvement centre ORR process at pH 13 two iron porphyrins. present a FeN4 site structure similar that porphyrin precursors....
Perfluorinated Fe phthalocyanine. Sitting at the top of volcano correlation for oxygen reduction reaction.
Experiments to investigate the catalytic pyrolysis of methane using an iron ore-based catalyst were carried out optimize activity and examine purity carbon produced from process for first time. Ball milling ore at 300 rpm varying times – 30 330 min was studied determine effect time on conversion. Optimal 270 led a five-fold increase in conversion ca. 1%–5%. Further grinding resulted decline 4% shown by SEM correspond particle size caused agglomeration. Data Raman Mössbauer spectroscopy H2...
The phase distribution of high aspect ratio, Fe-filled carbon nanotubes prepared by pyrolyzing a mixture powered ferrocene and ${\mathrm{C}}_{60}$ has been determined means M\"ossbauer spectroscopy. Our results for that characterization are closely related to the observation, after field cooling processes, hysteresis loop shift clearly suggest spatial which includes presence \ensuremath{\gamma}-Fe/\ensuremath{\alpha}-Fe interface. temperature dependence is discussed in terms localized...
In this paper we report the successful incorporation of silicon into SrFeO3−δ perovskite materials for potential applications as electrode solid oxide fuel cells. It is observed that Si doping leads to a change from tetragonal cell (with partial ordering oxygen vacancies) cubic one vacancies disordered). Annealing experiments in 5% H2/95% N2 (up 800 °C) also showed stabilization form Si-doped samples under reducing conditions, suggesting they may be suitable both cathode and anode...
We have compared the electrocatalytic activity of several substituted and unsubstituted Co Fe N4-macrocyclic complexes (MN4) for electro-reduction oxygen with directly adsorbed on edge plane pyrolytic graphite or carbon nanotubes (CNTs). In presence CNTs, one order magnitude higher surface concentrations MN4 catalysts per geometric area unit could be leading to a lower overpotential activities in same as commercially available Pt/C basic pH. From Koutecky-Levich regression analysis, total...