Facile stabilization of a cyclodextrin metal–organic framework under humid environment via hydrogen sulfide treatment

Increasing resistance to humid environments is a major challenge for the application of γ-CD-K-MOF (a green MOF) in real-world utilisation. γ-CD-K-MOF–H(2)S with enhanced moisture tolerance was obtained by simply treating MOF with H(2)S gas. XPS, Raman and TGA characterizations indicated that the H(2)S molecules coordinated with the metal centers in the framework. H(2)S acting as a newly available water adsorption potential well near the potassium centers protects the metal–ligand coordination bond from attack by water molecules and thus improves the moisture stability of MOF. After 7 days exposure in 60% relative humidity, γ-CD-K-MOF–H(2)S retained its crystal structure and morphology, while γ-CD-K-MOF had nearly collapsed. In addition, the formaldehyde uptake tests indicated that γ-CD-K-MOF retain their permanent porosity after interaction with H(2)S. This simple and facile one-step strategy would open a new avenue for preparation of moisture stable MOFs for practical applications.