Electrocatalysis of oxygen reduction at electrodeposited molybdenum phosphate-based films
This work reports an electrode material containing molybdenum phosphate that shows a very interesting behavior as an electrocatalyst for the reduction of oxygen to water (ORR) in acid medium. The material is electrodeposited on a glassy carbon electrode from a solution of Mo(VI) and Co(II) in phosph...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2012 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/96473 |
| Acceso en línea: | http://hdl.handle.net/11336/96473 |
| Access Level: | acceso abierto |
| Palabra clave: | OXYGEN REDUCTION MOLYBDENUM PHOSPHATE ELECTROCATALYSIS Pt-FREE CATHODES https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Sumario: | This work reports an electrode material containing molybdenum phosphate that shows a very interesting behavior as an electrocatalyst for the reduction of oxygen to water (ORR) in acid medium. The material is electrodeposited on a glassy carbon electrode from a solution of Mo(VI) and Co(II) in phosphate buffer at pH = 7. Cobalt is required to obtain a compact and uniform film. It is a non-crystalline solid conformed by metal oxide and phosphate groups that, according to XPS analysis, contains mostly Mo(VI) and a small fraction of Mo(V). Even though most of the Co-containing phase dissolves in acid, the film keeps its integrity and shows stable ORR activity in acid at very low overpotentials (from -0.3 V). The observed current density reaches a very small limiting value (∼2 μA cm -2) that is independent of the mass-transport conditions and could be associated to the small fraction of Mo(V) centers that function as ORR active sites. Although the film is thermally stable up to temperatures of 400 °C, by heating the material at temperatures above 100 °C it looses its unusual ORR activity due to the complete oxidation of Mo(V) to Mo(VI). |
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