Compositional Engineering of Colloidal Nanoparticles for Energy Conversion
- Autores: Zishan Luo
- Directores de la Tesis: Andreu Cabot Codina (dir. tes.), María Ibáñez Sabaté (dir. tes.), Anna Vilà Arbonés (tut. tes.)
- Lectura: En la Universitat de Barcelona ( España ) en 2016
- Idioma: español
- Tribunal Calificador de la Tesis: Javier Rubio Garcia (presid.), Carolina Gimbert Suriñach (secret.), Neus Gomez Bastus (voc.)
- Programa de doctorado: Programa Oficial de Doctorado en Nanociencias
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX Dipòsit Digital de la UB
- Resumen
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.
