Synthesis of 3D hierarchical porous carbon as an electrode material for electric double layer capacitors

A green and efficient method is presented to synthesize 3D hierarchical porous carbon from a metal organic framework (MOF) formed by 1,4-benzenedicarboxylic acid and zinc nitrate hexahydrate using glucose as the carbon precursor. Glucose was infiltrated into the external surface and/or voids of the cubic MOF, then polymerized and carbonized to form porous carbon. In the meantime, MOF was decomposed into ZnO, which was further reduced by carbon (or CO) into Zn that evaporated during carbonization. The morphology and pore characteristics of the products can be adjusted by changing the reaction time. When the synthesized porous carbon was used as the electrode material for electric double layer capacitors, it exhibited a high initial specific capacitance of 175 F · g^-1 at 0.6 A · g^-1 and a high capacitance retention of 94.2% at 12 A · g^-1 in 1 mol/L NEt4BF4/propylene carbonate electrolyte.