Enhancing water resistance of metal-organic frameworks

Abstract

Developing metal-organic frameworks (MOFs) with high water resistance is of high significance because it can largely extend their applications, such as catalysis and adsorption in aqueous solutions. Herein, we present a typical MOF, i.e., CuBTC [Cu₃(BTC)₂(H₂O)₃]_n (BTC = benzene-1,3,5-tricarboxylate) with high water resistance by post-modification reactions with six commercially available silanes at room temperature, resulting in CuBTC@SILANE. Various techniques demonstrated that the modification successfully incorporates organosilicon moieties on the surface of CuBTC without altering its original structure, significantly enhancing its water resistance. In contrast to pristine CuBTC, CuBTC@SILANE maintains its crystallinity, morphology, and pore structure even after prolonged exposure to water. The modified MOF also exhibits superior stability in various solvents and enhances CO₂ adsorption efficiency, retaining high CO₂ adsorption capacity even after exposure to water for 1 day. This simple silane modification approach not only addresses the water sensitivity of CuBTC but also holds promise for extending the aqueous applications of other similar MOFs, thereby broadening their potential uses in catalysis and adsorption.