Person:
Prado Gonjal, Jesús De La Paz

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First Name
Jesús De La Paz
Last Name
Prado Gonjal
URI
https://hdl.handle.net/20.500.14352/76087
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Inorgánica
Area
Química Inorgánica
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Author: Muñoz Gil, Daniel ×

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Now showing 1 - 3 of 3
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    Anti-site disorder and physical properties in microwave synthesized RE2Ti2O7 (RE = Gd, Ho) pyrochlores
    (RSC Advances, 2015) Gómez-Pérez, Alejandro; Prado Gonjal, Jesús De La Paz; Muñoz Gil, Daniel; Andrada Chacón, Adrián; Sánchez Benítez, Francisco Javier; Morán Miguélez, Emilio; Azcondo, MaríaTeresa; Amador, Ulises; Schmidt, Rainer
    In this work we report on the microwave assisted synthesis of nano-sized Gd2Ti2O7 (GTO) and Ho2Ti2O7 (HTO) powders from the RE2Ti2O7 pyrochlore family (RE ¼ rare earth). Synchrotron X-ray powder diffraction was used to study RE–Ti cationic anti-site defects with concentrations that decrease in both samples with increasing temperature starting from 1100 C, and the defects disappear at 1400 ºC. SQUID magnetometry measurements revealed that GTO shows a predominantly anti-ferromagnetic structure, whereas HTO exhibits magnetic saturation and a ferromagnetic component at low temperature. Impedance spectroscopy data revealed strongly increased ionic oxygen vacancy conduction in HTO ceramic pellets as compared to GTO, which may be associated with a higher degree of oxygen vacancy disorder. This argument was supported by Raman spectroscopy data.
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    Microwave synthesis & sintering of Sm and Ca co-doped ceria ceramics
    (International Journal of Hydrogen Energy, 2015) Prado Gonjal, Jesús De La Paz; Heuguet, Romain; Muñoz Gil, Daniel; Rivera Calzada, Alberto Carlos; Marinel, Sylvain; Morán Miguélez, Emilio; Schmidt, Rainer
    In this work we report on the combined use of microwave (MW) heating sources for the powdersynthesisandthe ceramic sinteringofSmandCaco-doped ceria Ce0.8Sm0.18Ca0.02O1.9 polycrystalline materials for potential application as an electrolyte in intermediatetemperature solid oxide fuel cells (IT-SOFCs). We investigate the crystal structure, ceramic microstructure and the oxygen ion conductivity in detail and compare the latter to conventionally sintered ceramics. MW sintering of ceramic pellets leads to only slightly increased resistivity as compared to conventional sintering, but offers massive energy and time savings for potential industrial production processes. Exceptionally high oxygen ion conductivity without any significant electronic contribution was found in MW synthesized and MW sintered pellets, where the total resistivity, composed of grain boundary and bulk contributions, was found to be in the range of 0.5-1 kohmios at 500 ºC. Sm- and Ca co-doped ceria may be well-suited for electrolyte materials in IT-SOFCs.
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    Microwave synthesis & sintering of Sm and Ca co-doped ceria ceramics
    (International journal of hydrogen energy, 2015) Prado Gonjal, Jesús De La Paz; Heuguet, Romain; Muñoz Gil, Daniel; Rivera Calzada, Alberto Carlos; Marinel, Sylvain; Morán, Emilio; Schmidt, Rainer
    In this work we report on the combined use of microwave (MW) heating sources for the powder synthesis and the ceramic sintering of Sm and Ca co-doped ceria Ce_(0.8)Sm_(0.18)Ca_(0.02)O_(1.9) polycrystalline materials for potential application as an electrolyte in intermediate temperature solid oxide fuel cells (IT-SOFCs).We investigate the crystal structure, ceramic microstructure and the oxygen ion conductivity in detail and compare the latter to conventionally sintered ceramics. MW sintering of ceramic pellets leads to only slightly increased resistivity as compared to conventional sintering, but offers massive energy and time savings for potential industrial production processes. Exceptionally high oxygen ion conductivity without any significant electronic contribution was found in MW synthesized and MW sintered pellets, where the total resistivity, composed of grain boundary and bulk contributions, was found to be in the range of 0.5-1 kΩ at 500 ºC. Sm-and Ca co-doped ceria may be well-suited for electrolyte materials in IT-SOFCs.