Composites of porous materials with ionic liquids: Synthesis, characterization, and selective gas sorption applications

Hybrid composites prepared by combining ionic liquids (ILs) with porous materials have become an increasingly important research field over the last few years owing to their tunable physicochemical properties. The enormous and continuous growth in the number of publications on the synthesis of such IL/porous materials and their exceptional performances in many different applications, mainly in gas adsorption and separation applications, is a proof of importance of this field. Combined advantages of ILs and porous materials provide great potentials in gas sorption and separation owing to the superior performance measures of the hybrid composites. In this thesis, it was aimed to provide a contribute to the evolution of IL/porous material composites as a research field by considering two different types of porous materials, including metal-organic frameworks (MOFs) and carbonaceous-materials. Accordingly, in depth analyses on the synthesis methods, characterization techniques, and selective gas separation performance of IL-modified porous materials were conducted to provide important insights into the design of novel IL/porous material composites and to identify the most promising hybrid materials for gas adsorption and separation applications. Examination of the structural factors controlling the chemical and thermal stabilities of novel IL/MOF composites was made to elucidate the resulting changes in the physicochemical structure of pristine MOF upon the incorporation of IL. Results illustrated that the composite with the ligand-functionalized MOF exhibited a lower degree of decrease in the thermal stability limits compared to the those containing non-functionalized counterpart. Then, systematic changes in the structure of MOF were further investigated by incorporating the same IL, into the cages of three different Zr-MOFs and extraordinary performance improvements in the selective gas separation were achieved emphasizing the significance of MOF selection on the resulting molecular affinity. Motivated by the superior performance obtained through the presence of a surface IL layer, a core-shell type IL/MOF composite was designed by an integrated computational-experimental hierarchical approach for improved air separation application. Later on, an activated carbon (AC) was modified with IL to extend the scope of the field by utilizing a cost-effective and chemically robust porous material for enhanced CO2 separation performance. The main challenges and opportunities in synthesis methods, characterization techniques, and gas sorption applications of IL/porous materials were discussed in detail to create a road map for the era. Recent advances of the field addressed in this thesis will provide a more in-depth insight into the design and development of these novel hybrid materials and their replacement with conventional materials.