Chemical Stability of MIL-101(Cr) upon Adsorption of SO₂ and NO₂ under Dry and Humid Conditions

Abstract

High Resolution Image Download MS PowerPoint Slide A detailed understanding of the chemical stability of metal–organic frameworks (MOFs) in water and acidic and basic solutions currently exists; however, there has been comparatively little investigation into the chemical stability of MOFs in the presence of acid gas species that may be present in industrial settings. MIL-101(Cr), a MOF that is stable in liquid water as well as acidic and basic solutions, was tested for its stability upon exposure to the acid gases sulfur dioxide (SO 2 ) and nitrogen dioxide (NO 2 ). Successive breakthrough experiments of both SO 2 and NO 2 show that both gases lower the adsorption capacity of MIL-101(Cr), which is also observed by N 2 physisorption experiments. X-ray photoelectron spectroscopy (XPS) confirms the presence of sulfur and nitrogen species in MIL-101(Cr) after exposure to SO 2 and NO 2 species. In situ infrared spectroscopy experiments suggest that adsorption of SO 2 in MIL-101(Cr) is not completely reversible and that adsorption of NO 2 in MIL-101(Cr) causes some structural degradation similar to what has been previously observed in HKUST-1.