Destruction of Metal–Organic Frameworks: Positive and Negative Aspects of Stability and Lability

Abstract

Metal–organic frameworks (MOFs), constructed from organic linkers and inorganic building blocks, are well-known for their high crystallinity, high surface areas, and high component tunability. The stability of MOFs is a key prerequisite for their potential practical applications in areas including storage, separation, catalysis, and biomedicine since it is essential to guarantee the framework integrity during utilization. However, MOFs are prone to destruction under external stimuli, considerably hampering their commercialization. In this Review, we provide an overview of the situations where MOFs undergo destruction due to external stimuli such as chemical, thermal, photolytic, radiolytic, electronic, and mechanical factors and offer guidelines to avoid unwanted degradation happened to the framework. Furthermore, we discuss possible destruction mechanisms and their varying derived products. In particular, we highlight cases that utilize MOF instability to fabricate varying materials including hierarchically porous MOFs, monolayer MOF nanosheets, amorphous MOF liquids and glasses, polymers, metal nanoparticles, metal carbide nanoparticles, and carbon materials. Finally, we provide a perspective on the utilization of MOF destruction to develop advanced materials with a superior hierarchy for various applications.

Capture of toxic gases in MOFs: SO2, H2S, NH3 and NOx

“…As a consequence, MOFs constructed from divalent metals such Cu 2+ and Zn 2+ , typically show partial or total degradation under harsh conditions. 32 Due to the inertness of the Cr-O bond, Cr 3+ -based MOFs highly resistant to the attack of acid and base guests were reported. 33,34 As described above, the third material, MIL-101(Cr)-4F(1%), has the highest SO 2 adsorption among SO 2 -stable MOFs.…”

“…At this point, we can corroborate that frameworks constructed with trivalent cations are more stable than MOFs based on divalent cations (considering the stability of Irving-Williams series discussed above), as well that carboxylate ligands form with M 3+ cations stronger bonds than divalent cations with N-based ligands. 32 (iii) Defective sites. Crystal irregularities (composition inhomogeneities or defects) are fundamental characteristics of some solid-state materials and provide very particular physical and chemical properties.…”

SO2 Capture Using Porous Organic Cages

“… [21] However, the potentially high cost of production for the organic components, combined with (sometimes) challenging scalability makes deployment of these materials difficult. Perhaps the biggest hurdle is the poor chemical stability of many MOFs (and indeed other materials) to SO 2 , [22] which is an aggressively corrosive gas. This poses questions for the economics of capturing SO 2 using MOFs on industrial scales.…”

SO2 Capture Using Porous Organic Cages

“…[21] However,t he potentially high cost of production for the organic components, combined with (sometimes) challenging scalability makes deployment of these materials difficult. Perhaps the biggest hurdle is the poor chemical stability of many MOFs (and indeed other materials) to SO 2 , [22] which is an aggressively corrosive gas.T his poses questions for the economics of capturing SO 2 using MOFs on industrial scales.…”