Development of hybrid systems, based on organic matrix – supported metal nanoparticles@Metal-Organic Frameworks, for Photocatalysis and Polystyrene sensing.

This thesis presents the design of synergetic heterogenous catalysts, consisting in organic matrixes incorporating metal nanoparticles (MNPs), metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). A rationally designed interaction between the MNPs guest and the MOF host is the key to achieve synergetic functions in heterogenous catalytic system. MNPs are widely used in heterogeneous catalysis, owing to their physicochemical characteristics of high activity, high selectivity, and good stability. With the continuous advancement of science and technology, noble metal nanoparticles catalysts will continue to play a significant role in various fields with their small-size effect, surface effect and quantum-size effect.[1] However, small size metal nanoparticles applied in heterogeneous catalysis system may lead to sintering or aggregation, due to their intrinsic instability , with catalyst loss, low activity and performance. Therefore, maintaining the catalytic efficiency and conversion rate of reactions catalyzed by metal catalysts while maintaining high surface and metal content is a worthy research question. MOFs and COFs have a great potential for the development of heterogenous catalysts, due to their properties, large specific surface area, high porosity, tunable pore size, rich structural variability, and broad synthesis modification possibilities. Such as easy designability of MOFs, especially the extraordinarily high porosities and the tunable pore size, make them highly appealing for integration with the high catalytic activity of MNPs. However, some types of MOF are unstable in aqueous solution, the structure is prone to collapse. Fragility of MOFs, as well as leaching and aggregation at high temperatures of MNPs, need to be improved. COFs, as pure organic structures with abundant aromatic groups, have an electron conjugation effect, which is beneficial for electron transport. Photoactive COFs will be prepared. A composite matrix substrate, made of organic polymers or Covalent Organic Frameworks (COFs), will be used to improve the overall stability of the MOF integrating MNPs. Porosity and differential substrate affinity of composite materials may allow to regulate the selectivity towards the reactants, meanwhile making easier the recovery or stabilization of the composite material, thus enlarging the current application fields of heterogeneous catalysis over MNPs-based catalysts. To boost stability and reactivity of the resulting composites, suitable substances will be introduced to construct a heterojunction. The resulting materials will be studied for photocatalysis under oxygen to convert alcohol into aldehyde and hydrogen peroxide. Also metal organic frameworks based matrix materials are wildly used in molecular recognition due to their functional groups.[2] Metal nanoparticle, especially Au nanoparticles, have SPR effect, that could be applied in sensing.[3] Considering society development and humans activities, plastic litters are increasing every year. Polystyrene (PS) as a common used plastic components present in litters and it breaks down into smaller fragments or even nanoparticles, which exist in the environment and pass through the food chain, causing serious impacts on human health.[4] Nowadays, PS nanoplastic detection and removal are attracting increasing attention from researchers. In this thesis, metal doped MOFs matrix materials have been also applied for PS detection. Keywords Metal organic frameworks Covalent organic frameworks Metal nanoparticles (MNPs) Photocatalysis PS recognition