Metal Organic Frameworks for CO2 capture: understanding the role of defective sites and pores functionalization with a combined structural a

Defective sites in metal-organic frameworks (MOFs) have a great impact on the performance of CO2 capture, the mechanism of which changes depending on the type and nature of these defects found at the metal sites. However, a detailed mechanistic, structural, and electronic understanding of the adsorption-desorption process over defective sites in amine-functionalized MOFs, known in the literature as highly performing CO2 capture porous materials, is lacking. Here we propose a combined in situ hard-X-ray XAS and XRD study targeting metal sites and MOFs pores to gain a structural and electronic understanding of CO2 adsorption over defective sites on a series of amino-tagged Fe(III) pyrazolate-based MOFs. We expect our spectroscopic and structural results to unveil the stages of CO2 capture over defective sites and functionalized pores with unprecedented structural detail, thereby paving the way for the rational design of improved MOF materials for CO2 adsorption and separation.