Robust synthesis routes and porosity of the Al-based metal-organic frameworks Al-fumarate, CAU-10-H and MIL-160.

Aluminum-based metal-organic frameworks, Al-MOFs, have developed into one of the most promising MOFs for potential applications because of, inter alia, their hydrothermal stability and comparatively easy synthesis, and the availability of abundant, inexpensive and non-poisonous metal. Here, we evaluate the synthesis and porosity properties of the three MOFs aluminum fumarate (Alfum), CAU-10-H and MIL-160 involving the commercially readily available ligands fumaric, isophthalic and furandicarboxylic acid, respectively. The three Al-MOFs exhibit proven hydrothermal stability and water uptake to make them eligible for heat transformation applications. At the same time, it is important for applications that the synthesis and porous properties of these MOFs are robust, that is readily reproducible within certain limits. The typical solution synthesis of these MOFs was carried out with slight variations and compared with the literature to check if indeed the reported porosity data can readily be reproduced. Furthermore, dry-gel conversion (DGC) was implemented here for the synthesis of these MOFs and yielded products with higher total pore volumes due to the inherent aggregate formation under dry-gel synthesis conditions. The evaluation and our added syntheses ascertain that these Al-MOFs can be reproducibly synthesized with robust porosity properties, which are independent of the synthesis method, underscoring the potential of these MOFs for applications.