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Title: Compositional Engineering of Colloidal Nanoparticles for Energy Conversion
Author: Luo, Zhishan
Director: Cabot i Codina, Andreu
Ibáñez Sabaté, Maria
Keywords: Materials nanoestructurats
Nanostructured materials
Issue Date: 19-Dec-2016
Publisher: Universitat de Barcelona
Abstract: [eng] The main objective of this thesis focuses on compositional design and engineering colloidal NPs and their application in energy conversion. This principally included the synthesis and characterization of colloidal NPs, and in-depth exploration of their catalytic properties. Special focus is the synthesis and characterization of copper-based chalcogenides, bimetallic and multicompent metal oxide NPs. The results were shown in the series of articles which have been published or are under review in high impact peer-review journals. These works can be extracted to conclusions as following: (1) Copper-based chalcogenides NPs: Detailed synthetic routes to produce CZTS and CZTS-based HNPs i.e. CZTS-Au, CZTS-Pt and CZTS-Ag2S. The composition, size and shape control of CZTS NCs have been achieved by tuning the precursor concentration, surfactants, gas bubbling and heating ramp. This synthetic strategy method can be easy to scale up to grams at the same time keeping above 90% yield per batch by a simple vacuum free heating-up method. We used CZTS NCs as electrocatalysts with controlled crystal phases for the ORR measurements. First-principles calculations and experiments both indicated the kesterite CZTS NCs exhibit improving electrocatalytic activities toward ORR. In additional, monodisperse CZTS-Au and CZTS-Pt HNPs were obtained base on CZTS as seeds by seed-mediated growth method. Various characterizations confirm the structure of noble-semiconductors HNPs. Such HNPs were investigated on photocatalytic degradation of dye and hydrogen evolution reaction in water, exhibited high catalytic active. The research of CZTS-based HNPs is extended to a detailed synthesis of CZTS-Ag2S HNPs involving cation exchange reaction. The structure and composition of CZTS-Ag2S could be tuned by control the ration of Ag precursors and CZTS seeds. When employing CZTS-Ag2S as sensitizers apply photoelectrochemical cell for water splitting, showed improved photocurrent response under visible-light illumination. (2) Bimetallic NPs: The synthesized Pd2Sn NPs were successfully used solution-based strategy. A mechanism of morphology structure was discussed detail based different ratio of OLA, chlorine and TOP precursors. When evaluating catalytic properties of geometry of Pd2Sn NPs, reduction of nitrophenol, water denitration and EOR were measured resulting in Pd2Sn NRs had outperformance catalytic active over Pd2Sn spherical NPs, while Pd2Sn alloy NPs exhibited better catalytic performance compare to Pd NPs. The formation of novel Au-Pd2Sn heterostructured NRs was described in detail as well. Au-Pd2Sn heterostructured NRs were synthesized via a seed-mediated growth method, which Au domains were selected to grow on the Pd2Sn seeds. The result establishes a new strategy for the development of multifunctional nanomaterials. (3) Multicompent metal oxide NPs: Mn3O4@CoMn2O4 core-shell and Mn3O4@CoMn2O4-CoO HNPs were prepared via partial cation exchange reaction via Mn3O4 seeds NPs and different cobalt precursors, which playing a crucial role whether additional nucleation of a CoO phase depending on the coordination ability of cobalt precursors. The lower coordination ability of cobalt perchlorate had a higher reactivity to grow CoO phase on Mn3O4@CoMn2O4 to form Mn3O4@CoMn2O4-CoO HNPs. In particular, such HNPs showed a superior catalytic activity and stability over the core shell catalysts and state-of-the-art electrocatalysts for ORR and OER in alkaline solution. Based on this colloidal synthetic route, Fe3O4@NixFe3-xO4 core shell NPs was obtained involving nickel perchlorate precursors to Fe3O4 seeds solution. The fabrication of this core shell NPs and ITO glass to form thin film as water oxidation catalyst exhibited an improved catalytic activity. This colloidal synthetic route offers an easy scale-up, low temperature and ambient pressure protocol to design earth-abundant, cost-effective and high activity water oxidation catalysts.
[spa] El objetivo principal de esta tesis se centra en el diseño de ingeniería de composición y NP coloidal y su aplicación en la conversión y almacenamiento de energía. Esto incluye principalmente la síntesis y caracterización de los NP coloidales, y la exploración a fondo de sus propiedades catalíticas. Se prestará especial atención es la síntesis y caracterización de calcogenuros a base de cobre, óxido de metal NP bimetálicas y multicompent. Estos trabajos se pueden extraer con el resumen de la siguiente manera: (1) calcogenuros base de cobre NP: basados ​​en CZTS rutas sintéticas detalladas para producir CZTS y heterostructured NP es decir CZTS-Au, Pt y CZTS-CZTS-Ag2S. La composición, el tamaño y la forma de control de CZTS CN se han conseguido mediante la regulación de la concentración de precursor, tensioactivos, burbujeo de gas y rampa de calentamiento. Utilizamos CZTS CN como electrocatalizadores con fases de cristal controlados para las mediciones de la reacción de reducción de oxígeno con cálculos y experimentos de primeros principios. En CZTS-Au adicionales, monodispersas, CZTS-PT y CZTS-Ag2S hetero-NP se obtuvieron sobre la base CZTS como semillas por el método de crecimiento de la semilla mediada. Tal Hetero-NP se investigaron sobre la degradación fotocatalítica de tinte, reacción de desprendimiento de hidrógeno en agua y celular fotoelectroquímico para la disociación del agua, exhibido alta catalítica activa. (2) bimetálica NP: Los Pd2Sn NP sintetizados se utilizan con éxito la estrategia basada en la solución. Un mecanismo de la estructura de la morfología se discutió detalle. Al evaluar las propiedades catalíticas de la geometría de Pd2Sn NP, la reducción de nitrofenol, desnitrificación del agua y la reacción de oxidación del etanol resultante se midieron en Pd2Sn NR había de resultados superiores activa catalítica sobre Pd2Sn esférica y Pd NP. La formación de la novela Au-Pd2Sn heterostructured NR se sintetizaron mediante un método de crecimiento de la semilla mediada, que fueron seleccionados Au dominios de crecer en las semillas de Pd2Sn. El resultado establece una nueva estrategia para el desarrollo de nanomateriales multifuncionales. (3) NP de óxido metálico Multicompent: Mn3O4@CoMn2O4 core-shell y Mn3O4@CoMn2O4-CoO hetero-NP se prepararon mediante la reacción de intercambio catiónico parcial a través de Mn3O4 semillas NP y diferentes precursores de cobalto. Tal Hetero-NP mostró una actividad catalítica y estabilidad superiores en los catalizadores de núcleo y corteza y electrocatalizadores el estado de la técnica para el oxígeno reacción de reducción / evolución en solución alcalina. En base a esta vía de síntesis coloidal, Fe3O4@NixFe3-xO4 de núcleo y corteza NP se obtuvo con precursores de perclorato de níquel a una solución semillas Fe3O4. La fabricación de este núcleo NP cáscara y el vidrio ITO para formar la película delgada como catalizador de oxidación en agua exhibe una actividad catalítica mejorada.
Appears in Collections:Tesis Doctorals - Departament - Electrònica

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