(92d) Investigating the Effect of Trace Levels of Manganese Ions during Solvothermal Synthesis of Muf-16 on CO2 Uptake Capacity

While multiple MOF synthesis routes have been explored in literature, the effects of impurities and contaminants in reaction mixtures for MOFs have only rarely been investigated. The impact of these impurities is a crucial factor to consider while attempting to scale up these materials. The presented work reports the surprisingly positive impact of presence of Manganese ions in the synthesis mixture for crystallization of MUF-16 (MUF = Massey University Framework), a Co based MOF, on its CO₂ adsorption capacities. Through extensive characterizations including XRD, SEM, FTIR-ATR, UV-Vis spectroscopy, TGA, XPS and EXAFS and density functional theory (DFT) calculations, we hypothesize that the differences in CO₂ adsorption among materials with differing synthesis routes arises from variations in the local environment around the cobalt metal center. We speculate that manganese ions get inserted into the structure during crystallization and act as catalysts for ligand substitution leading to octahedral geometries for Cobalt metal center in the MOF which leads to higher CO₂ uptakes.