Synthesis, Characterization, and Shaping of UiO-67 Metal-Organic Frameworks

Abstract

This PhD thesis investigates the flexibility of metal-organic frameworks (MOFs) materials, particularly focusing on their adaptable synthesis and shaping techniques. MOFs, known for their dynamic framework structures and flexible linkers, allow researchers to design new and existing porous materials for specific applications, such as catalysis and environmental protection. The research covers a range of topics, including synthesis, characterization, shaping, and catalytic testing, with particular emphasis on the flexible properties of MOFs.

Chapter 2 focuses on the application of MOFs in active coatings on surfaces and functionalized fabrics to deactivate biological and chemical toxins, a crucial topic in light of the global health crisis induced by the SARS-CoV-2 outbreak. The chapter discusses advancements in metal- and metal-oxide-based catalysts for inactivating chemical and biological threats. It also explores MOF applications in textiles, which are designed to capture and degrade chemical warfare agents. Despite progress, challenges remain, particularly in translating laboratory results to real-world conditions, such as creating multifunctional protective suits that are durable and capable of detoxifying toxins while remaining comfortable. The chapter highlights the promise of MOFs in addressing these challenges, but also the need for improved manipulation onto fibers and long-term stability.

Chapters 3, 4, and 5 delve into the catalytic potential of MOFs and their manipulation for specific applications. In Chapter 3, the focus is on the catalytic activity of platinum nanoparticles (Pt-NPs) embedded within the UiO-67 MOF structure, specifically investigating their role in the CO2 hydrogenation reaction. The study examines the effects of reduction and pyrolysis treatments on Pt-NPs, finding that certain treatment processes improve the selectivity for methanol formation. This chapter emphasizes the importance of understanding the catalytic properties of MOFs and their potential for CO2 conversion.

Chapter 4 investigates surface-mounted MOFs (SURMOFs), which offer promising in situ measurement capabilities. The chapter discusses the synthesis and characterization of three different SURMOF materials: UU-1, ZIF-8, and UiO-67. It explores how different anchor molecules, substrates, and synthetic conditions affect the growth and morphology of these SURMOFs. The chapter also addresses the limitations of current analytical techniques and proposes transmission-based characterization on transparent substrates. The findings highlight the importance of spectroscopic characterization in understanding the behavior of SURMOFs during various processes, offering insights for their application in fields like sensing, separation, and catalysis.

Finally, Chapter 5 addresses the challenge of shaping MOFs via mechanical pressure by presenting a synthesis procedure that forms MOF beads through entanglement with chitosan (CS). This method eliminates the need for mechanical pressure, which can be detrimental to MOF structures. The study compares two synthesis procedures—one-pot synthesis (OPS) and post-synthetic functionalization (PSF)—and finds that OPS leads to better incorporation of MOFs into CS beads, resulting in higher thermal stability. Overall, this thesis demonstrates the versatility of MOFs in catalysis, environmental protection, and material science, while also addressing the challenges associated with shaping and long-term stability.