Abstract
Distinctive Cr-MOF@Da composites have been constructed using chromium-based metal-organic frameworks (MOFs) and diatomite (Da). The new materials have hierarchical pore structures containing micropores, mesopores and macropores. We have synthesized various morphologies of the MOF compound Cr-MIL-101 to combine with Da in a one-pot reaction step. These distinctive hierarchical pore networks within Cr-MIL-101@Da enable exceptional adsorptive performance for a range of molecules, including hydrogen (H2), carbon dioxide (CO2) and water (H2O) vapor. Selectivity for H2 or CO2 can be moderated by the morphology and composition of the Cr-MIL-101 included in the Cr-MOF@Da composite. The encapsulation and growth of Cr-MIL-101 within and on Da have resulted in excellent water retention as well as high thermal and hydrolytic stability. In some cases, Cr-MIL-101@Da composite materials have demonstrated increased thermal stability compared with that of Cr-MIL-101; for example, decomposition temperatures >340 ℃ can be achieved. Furthermore, these Cr-MIL-101@Da composites retain structural and morphological integrity after 60 cycles of repeated hydration/dehydration, and after storage for more than one year. These characteristics are difficult to achieve with many MOF materials, and thus suggest that MOF–mineral composites show high potential for practical gas storage and water vapor capture.
Highlights
Metal-organic frameworks (MOFs) are a class of crystalline materials with high potential for applications that require adsorption, separation, catalysis and drug delivery [1,2,3,4,5]
A range of morphologies and particle sizes for Cr-MIL-101 can be developed with variations in synthesis conditions, such as the substitution of H2 O for hydrofluoric acid (HF) [24,35], or by incorporating adducts to provide functionality [36]
A consistent synthesis method for Cr-MIL-101 has been used to minimize the influence of metal-organic frameworks (MOFs) synthesis conditions on MOF@Da composite performance
Summary
Metal-organic frameworks (MOFs) are a class of crystalline materials with high potential for applications that require adsorption, separation, catalysis and drug delivery [1,2,3,4,5]. Other MOF compositions have been synthesized and evaluated for the capture and storage of CO2 with some success [13,14] In these cases, a systematic approach to the design of a MOF for the adsorption of either H2 or CO2 often requires adjusting compositions of the metal, the ligand or the solvent to achieve an appropriate pore size and structure. Replacing molecular building blocks (MBBs) such as metal ions and organic ligands is a common method to chemically tune MOFs [15,16]. This approach usually requires the utilization of different precursor chemistries, and leads to different types of products [16,17].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
