Six Isomorphous Window‐Beam MOFs: Explore the Effects of Metal Ions on MOF‐Derived Carbon for Supercapacitors.

Six isomorphous metal–organic frameworks (MOFs) with a 3D window‐beam architecture have been synthesized from solvothermal reactions, and are named Zn, Cd, Ni, Co, Mn and Cu‐MOF, respectively. The series of MOFs was utilized as precursors to synthesize MOF‐derived carbon with different morphologies. Zn and Cd‐MOFs lead to the derivation of porous carbons (PCs), which exhibit remarkable BET specific surface areas. For derivates of Ni, Co and Mn‐MOFs, graphitized carbons (GCs) show some carbon graphitization, but their BET specific surface areas are relatively small. C‐Cu has the smallest BET specific surface area, and there is no carbon graphitization. Therefore, the metal ion of the parent MOF exerts a crucial effect on the preparation of MOF‐derived carbon, such as the pore‐forming effect of Zn and Cd species, and catalytic graphitization of Ni, Co, and Mn species. The capacitances of MOF‐derived carbon follow the sequence of PCs>GCs>C‐Cu, which reveals that the specific surface area plays a dominant role in the capacitive performance of electrical double layer capacitors (EDLCs), and that the graphitization could improve the capacitance. Significantly, PC‐Zn exhibits the best specific capacitance (138 F g−1 at 0.5 Ag−1), and excellent life cycle, which can be applied as an electrode material in supercapacitors. Window of opportunity: A series of isomorphous MOFs have been employed as precursors for preparing carbon materials through the calcination‐thermolysis strategy. It is found that the metal species of parent MOFs exert crucial effects on MOF‐derived carbon. The correlation between capacitance and internal morphology has been intensively discussed. Moreover, PC‐Zn exhibits remarkable capacitances, and is an electrode material for supercapacitors. [ABSTRACT FROM AUTHOR]