Self-Assembly and Mass Transport in Membranes for Artificial Photosynthesis
Notice bibliographique
Résumé
Recent environmental factors have triggered a strong interest towards the development of scalable technologies that can increase the share of renewable sources into our energy mix. Artificial photosynthesis systems are a promising alternative as they can simultaneously capture and store solar energy in the form of a fuel. These systems are based on photoelectrochemical (PEC) cells that can take low energy density reactants such as water and/or carbon dioxide and transform them into energy dense hydrogen or carbon containing molecules via light-driven processes. Deployable solar-fuel generators need to be able to produce fuels in a robust, scalable, and efficient manner. Despite the large number of studies focusing on this technology since its inception in the early 1970's, a system that can satisfy those three requirements does not exist. Significant innovation is required to develop cost-effective components that can perform the light-absorption, catalytic redox reaction, ion transport and product separation requirements. Additionally, understanding of component performance in integrated devices is crucial for developing high efficiency solar-fuel generators.This dissertation focusses on several aspects of component integration in solar-hydrogen generators. The initial focus involves the development of self-assembly techniques of nanometer scale units to obtain architectures necessary for solar-fuel devices. Starting with solutions of semiconducting nanorods and polymers, this work demonstrates that by controlling the evaporation rate during solvent casting, arrays of vertically aligned nanorods embedded in polymer films can be obtained over large areas (> 1 cm2). This architecture is desirable for the integration of hydrogen generating nanorods into integrated water splitting membranes, where H2 and O2 are evolved at physically separated sites. This work also describes how the structure of proton conducting membranes (Nafion®) is affected at inorganic interfaces such as the ones present in solar-fuels devices. The effects of thin-film confinement and wetting interactions are studied in Nafion thin-film model systems using a combination of X-ray scattering and mass transport characterization techniques. These studies show how confinement of Nafion films to thicknesses below 10 nm results in significant limitations to self-assembly, disruption of phase separation in the material and ultimately decrease in ionic conductivity. Wetting interaction also play a role in the orientation of conducting domains in the material. Hydrophobic surfaces results in a parallel orientation of ionic domains while films cast on hydrophilic substrates result in an isotropic orientation of domains. The differences in domain orientation also impact the mass transport behavior of the material.Additionally, this dissertation covers several topics related with the integration of components for the fabrication of practical hydrogen generators. Here we describe the development of a microfluidic test-bed for the incorporation of catalytic and membrane components in scales amenable for research. This tool allows for the simple exchange and quantitatively assessment of the performance of integrated electrochemical fuel generating devices as well as each of the individual components that participate in the process. Lastly, this work also describes engineering solutions that allow both membrane-separated water electrolyzers and solar hydrogen generators to operate under buffered electrolytes. This is achieved by using supporting electrolytes to carry the ionic current through the membrane while controlled convective streams around the membranes are implemented to avoid the formation of large concentration gradients between reaction sides. This development opens up the space of operating electrolytes for the incorporation of wide range of components that are not stable under strong basic or acidic conditions.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».