Síntesis de catalizadores de Ni y/o Co promovidos por Ce y/o Pr obtenidos a partir de hidróxidos de doble capa para la producción de hidrógeno por reformado de etanol con vapor oxidativo
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Autores
Muñoz Cárdenas, Mónica del Pilar
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Tipo de contenido
Trabajo de grado - Doctorado
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EspañolFecha de publicación
2014-12-05
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La presente tesis doctoral se enmarca dentro del estudio y desarrollo de sistemas catalíticos para la producción de hidrógeno, vía reformado de etanol con vapor oxidativo (OSRE). Los objetivos y la estrategia planteada en este trabajo condujeron al diseño, síntesis y caracterización integral de óxidos mixtos de Ni y/o Co, derivados de precursores tipo hidrotalcita, los cuales exhibieron un buena actividad y estabilidad catalítica en el OSRE. No obstante, estos sólidos presentaron la formación de depósitos carbonáceos en superficie por lo cual esta investigación también incluyó la evaluación del efecto promotor del Ce y/o Pr para disminuir este tipo de desactivación catalítica logrando la obtención de catalizadores activos durante 100 h de reacción con una menor generación de precursores de coque. Adicionalmente, este estudio investigó el uso de ultrasonido o microondas en la síntesis de estos catalizadores, lo que condujo a la producción de sólidos con propiedades y actividades catalíticas similares a los sintetizados por el método convencional pero empleando menores tiempos de preparación y con el mejoramiento de algunas características como la basicidad y movilidad de las especies de oxígeno.
Abstract. This thesis is into the study and development of catalytic systems for hydrogen production via oxidative steam reforming of ethanol (OSRE). The objectives and the strategy proposed led to the design, synthesis and characterization of mixed oxides of Ni and /or Co derived from hydrotalcite-like precursors. These solids exhibited good catalytic activity and stability for the OSRE. However, the formation of carbonaceous species on the surface was evidenced. In order to decrease this kind of catalyst deactivation, the promoting effect of Ce and /or Pr was also evaluated. In fact, when those elements were introduced in the Ni-Co system, a low coke formation after 100 h of reaction was detected. Additionally, the use of ultrasound (US) or microwaves (MW) during the synthesis was investigated. The method assisted by US or MW generated solids with properties similar to those synthesized by the conventional method but some features like basicity and the oxygen species mobility were improved, besides a significant reduction of the synthesis time.
Abstract. This thesis is into the study and development of catalytic systems for hydrogen production via oxidative steam reforming of ethanol (OSRE). The objectives and the strategy proposed led to the design, synthesis and characterization of mixed oxides of Ni and /or Co derived from hydrotalcite-like precursors. These solids exhibited good catalytic activity and stability for the OSRE. However, the formation of carbonaceous species on the surface was evidenced. In order to decrease this kind of catalyst deactivation, the promoting effect of Ce and /or Pr was also evaluated. In fact, when those elements were introduced in the Ni-Co system, a low coke formation after 100 h of reaction was detected. Additionally, the use of ultrasound (US) or microwaves (MW) during the synthesis was investigated. The method assisted by US or MW generated solids with properties similar to those synthesized by the conventional method but some features like basicity and the oxygen species mobility were improved, besides a significant reduction of the synthesis time.