Nuevos óxidos de Ag y Cu por intercalación electroquímica y otros métodos suaves
With the aim of exchanging Hg by Ag in the copper-based superconductors with the highest Tc, the synthesis of simple Ag-Cu oxides (not known even in nature) became the first target. That work brought as a result the first known Ag-Cu oxide, Ag2Cu2O3, and also the second, Ag5Pb2-xCuxO6, both synthesi...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2004 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | español |
| OAI Identifier: | oai:ddd.uab.cat:37101 |
| Acceso en línea: | https://ddd.uab.cat/record/37101 |
| Access Level: | acceso abierto |
| Palabra clave: | Òxids de coure i plata Electroquímica |
| Sumario: | With the aim of exchanging Hg by Ag in the copper-based superconductors with the highest Tc, the synthesis of simple Ag-Cu oxides (not known even in nature) became the first target. That work brought as a result the first known Ag-Cu oxide, Ag2Cu2O3, and also the second, Ag5Pb2-xCuxO6, both synthesized by soft chemistry methods (coprecipitation). In both cases, Ag and Cu show their usual oxidation state in oxides (AgI, CuII). The present work describes the result of latter research, having a new perspective: to try to synthesize new Ag-Cu phases, modifying their oxidation states or introducing other metals, in other to achieve new physical properties. In this sense it represents the logical continuation in the original scheme that arouse from the existence of Cu-Hg superconductors, but it also focus in the chemistry of an up to now unknown family, that of Ag-Cu oxides, in terms of its synthesis, properties, redox behavior, etc. In the way we have found both new synthetic methods, important in terms of applications and novelty, and unexpected results related with charge distribution and atomic structure. Thus, the new oxide Ag2Cu2O4 has been synthesized by electrochemical oxidation of the slurries of everal starting materials, which represents a new synthetic route for solid phases. This oxide shows quite peculiar properties, in terms of charge distribution (having Ag with an oxidation state over +1, with both Cu and O participating in the oxidation) and sensitivity to radiation, which can induce charge distribution. We have also been able to reproduce the synthesis of Ag2Cu2O4 using other methods: oxidation with ozone and by hydrothermal synthesis. The morphology, oxygen content and properties of Ag2Cu2O4 have a clear dependence on the synthetic method utilized. Also, the hydrothermal synthesis has yielded two new quaternary Ag-Cu oxides, Ag2MnCuO4 and Ag2Cu3Cr2Ox which are presently being studied and characterized. |
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