(183m) Conversion of Hydroxy Double Salts for Scalable Synthesis of Metal-Organic Frameworks

With high surface area and large porosity, metal-organic frameworks (MOFs) have been a class of attractive adsorbent materials in recent years. Previous research and industrial attempts have shown that MOFs are promising for applications in gas storage for fuel cell vehicles and large-scale capture of carbon dioxide. These potential industrial applications would require millions of tons of MOFs produced globally every year. However, the low space-time yield (STY) of traditional solvothermal method, the harsh synthesis conditions, and the high production cost of MOFs have limited their commercialization and industrial applications. Strategies to efficiently synthesize MOFs in a large scale are therefore highly desired.

Hydroxy double salts (HDSs) are layered compounds featured with fast anion exchange ability, and have been reported as key intermediates for facile MOF formation. Here, we extended this method to grow zeolitic imidazolate frameworks and fumarate-based MOF structures rapidly at room temperature. We synthesized [M_1-xZn_x(OH)_2-y](NO₃)_y/z∙nH₂O (M=Co, Cu) HDS structures by hydrolyzing ZnO in aqueous solution of M(NO₃)₂ at room temperature. These HDSs exhibit fast exchange rate with imidazolate and fumarate anions and subsequently convert to MOF structures. We will show how the shape and size of the organic linker anions affect HDSs conversion to MOFs, and discuss the differences between the conversion reaction and the intercalation reaction for HDSs during anion exchange.