Tunable Electrochemistry of Electrosynthesized Copper Metal-Organic Frameworks

Metal-organic frameworks (MOFs) synthesized using different organic ligands are expected to have varied morphology and properties. Herein, three copper MOFs (Cu-MOFs) are electrosynthesized using a simple and direct reduction approach and three organic ligands: 1,3,5-benzenetricarboxylic acid, 1,4-benzenedicarboxylic acid, and 1,2,4,5-benzenetetracarboxylic acid. The as-synthesized Cu-MOFs exhibit varied morphology. Their electrochemistry is further explored via investigating the natures of their capacitive, faradaic, and electrocatalytic behavior. The stability of these Cu-MOFs is also checked during the course of electrochemical measurements. The secondary built units of organic ligands with copper ions are found theoretically and experimentally to determine both the morphology and active sites of Cu-MOFs. Namely the electrochemistry of Cu-MOFs is dependent on the used organic ligands. Cu-MOF synthesized using 1,3,5-benzenetricarboxylic acid owns better electrochemistry than that using 1,4-benzenedicarboxylic acid or 1,2,4,5-benzenetetracarboxylic acid. These MOFs keep their compositions and crystallinity unchanged in short times but loss them for long electrochemical running times. Therefore, the properties and applications of MOFs are designable and can be optimized during the course of reduction electrosynthesis processes via selecting organic ligands and metal ions.