Structural Deterioration of Well‐Faceted MOFs upon H₂S Exposure and Its Effect in the Adsorption Performance

Abstract

The structural deterioration of archetypical, well‐faceted metal–organic frameworks (MOFs) has been evaluated upon exposure to an acidic environment (H2S). Experimental results show that the structural damage highly depends on the nature of the hybrid network (e.g., softness of the metal ions, hydrophilic properties, among others) and the crystallographic orientation of the exposed facets. Microscopy images show that HKUST‐1 with well‐defined octahedral (111) facets is completely deteriorated, ZIF‐8 with preferentially exposed (110) facets exhibits a large external deterioration with the development of holes or cavities in the mesoporous range, whereas UiO‐66‐NH2 with (111) exposed facets, and PCN‐250 with (100) facets does not reflect any sign of surface damage. Despite the selectivity in the external deterioration, X‐ray diffraction and gas adsorption measurements confirm that indeed all MOFs suffer an important internal deterioration, these effects being more severe for MOFs based on softer cations (e.g., Cu‐based HKUST‐1 and Fe‐based PCN‐250). These structural changes have inevitable important effects in the final adsorption performance for CO2 and CH4 at low and high pressures.

Hydrogen sulfide capture and removal technologies: A comprehensive review of recent developments and emerging trends

“…The major theme in most of the studies on H 2 S capture using MOFs is the lack of structural stability under external stimuli, especially in the presence of H 2 S [339,340]. In general, this property should be possible to be tuned by varying the nature of the metal sites.…”

Atomic layer deposition of nano-scale molybdenum sulfide within a metal–organic framework for highly efficient hydrodesulfurization

“…However, due to the instability of most MOFs in a hydrogen sulfide atmosphere, the fixation of metal sulfides on MOFs is rare. 30,31 In recent years, zirconium-based MOF NU-1000 has attracted a lot of attention because of its strong resistance to hydrogen sulfide. 32 NU-1000 is especially suitable for use as a carrier for metal sulfide deposition for the following reasons: (1) the available hydroxy/water ligands on the Zr 6 node in NU-1000 can be combined with an ALD precursor, [33][34][35][36] (2) large mesoporous channels can satisfy the diffusion of ALD precursors and reaction substrates and promote the effective binding of catalysts and substrates, 37 (3) high stability under the reaction conditions required for desulfurization applications, 32 (4) with high specific surface area, more active centers could be obtained, and the adjustability of the structure may provide synergistic catalytic activities.…”