Guest size limitation in metal-organic framework crystal-glass composites

Metal-organic framework crystal-glass composites (MOF CGCs) have previously been formed by embedding crystalline MIL-53(Al) within a ZIF-62 glass (a(g)ZIF-62) matrix. Here we highlight thermal stability considerations in the formation of MOF CGCs, and subsequently report the synthesis of two novel MOF CGCs, by incorporating MIL-118 and UL-MOF-1 within a(g)ZIF-62. These new materials, alongside the prototypical MOF CGC, formed using MIL-53(Al), were studied using scanning electron microscopy, powder X-ray diffraction, and gas sorption techniques. The gas uptake in composites formed from MIL-118C and UL-MOF-1 is largely dominated by the a(g)ZIF-62 matrix, suggesting that to improve the porosity of the MOF CGC, the matrix porosity must be improved, or a percolation threshold must be overcome.

Automated summary

This study focuses on the thermal stability considerations in the formation of metal-organic framework crystal-glass composites (MOF CGCs), and introduces the synthesis of two novel MOF CGCs. The research shows that gas uptake in composites is largely influenced by the a(g)ZIF-62 matrix, indicating that improving the matrix porosity or overcoming a percolation threshold is crucial for enhancing the porosity of MOF CGCs.