Investigations into the Enhanced Gas Storage Capabilities of Photoresponsive and Redox Active Metal-Organic Frameworks

Abstract

The energy-efficient capture and release of gas molecules, mainly carbon dioxide, methane, hydrogen, and small hydrocarbons, has been an area of significant academic and industrial interest due to their relevance for alternative energy applications. Porous materials such as Metal-Organic Frameworks (MOFs) offer a unique approach towards these research goals as they provide a tunable platform for sorptive systems to reach DOE gas storage targets. However, because of the microporous nature of MOFs, gas adsorption performance is dominated by high uptake capacity at low pressures, as many applications operate under constrained pressure conditions, typically well above this high-capacity low pressure region, limiting their applications. Hence, post-synthetic modifications, such as thermal decarboxylation, and the use of stimuli-responsive materials, particularly light-induced switchable adsorption (LISA) processes, offer a unique alternative and can be coupled to enhance the real working capacity towards a desired goal. Within this thesis I discuss my studies on the mechanism of both the LISA process and the thermal decarboxylation process within MOFs and the governing influences for each. Both the LISA and thermal decarboxylation systems can be independently utilized to gain a higher gas storage working capacity compared to the base material. The utilization of each process independently is explored in detail in chapter 2 and 3 respectively. However, these approaches can also be utilized as a coupled system, the results of this and the governing influences of the coupled system are also explored in chapter 4. This body of work aims to demonstrate the usability of two processes towards enhanced gas working capacity and shows the potential of this low-energy release coupled system.