Solution Processable Nickel, Iron Metal-Organic Frameworks with Tuneable Oxygen Species : From Theoretical Prediction to Applications

The lack of solution processability of metal-organic frameworks (MOFs) has been a major obstacle to hamper their practical applications. At present, a common belief is that the solution processability of MOFs can only be improved by functionalized with extra additives. In this work, we have firstly predicted through density function theory (DFT) that MOFs’ self-contained oxygen species can effectively tune their solution processability. Guided by this interesting prediction, an experimental protocol has been demonstrated for manipulating nickel, iron-MOF nanoparticles with different oxygen percentages (30%~55%) through O2 plasma treatment, which can continuously tune the zeta potentials of MOF aqueous solutions from -13.3 to -29.4 mV. Potential applications have been explored for these negatively charged yet homogeneously dispersed MOFs, which can be sorted according to their particle sizes through surface charge induced selective sedimentation, and small-particle-size MOFs are desirable for electrocatalytic reactions. Finally, our approach has been extended to MOFs with other organic ligands (2,5-thiophene dicarboxylic acid)