New route for the synthesis of Co-MOF from metal substrates

Abstract

The synthesis of MOFs (Metal Organic Frameworks) from reduced metal sources could provide an elegant approach for the recovery of metal waste or to produce MOF coatings on metal or metal alloy surfaces, but this process has not been studied in depth so far. The difficulty of such MOF synthesis lies in the fact that the metal in the MOF structure is oxidized, necessitating in situ metal oxidation during synthesis when starting from reduced metal sources. This can be achieved by various methods including acid etching of the metal. In this method, the metal can be dissolved and oxidized at the same time (pH ~ <7) and the ligand can be deprotonated (pH ~> 6) to react with the oxidized metal. We hypothesize that Co MOF can be prepared by this method, since the redox reactions of cobalt are possible in the same pH range in which many MOF linkers can be deprotonated. Therefore, the synthesis of two different Co MOFs using acid etching has been studied. The MOFs prepared (ZIF-67 and MOF-71) have shown the same properties as reference materials prepared from oxidized metal sources and have been studied in water-ethanol separation. • Metallic cobalt has been used for the synthesis of MOF. • Experimental conditions has been set to get the desired structures. • MOF-71 flexibility has been studied by water adsorption.