Pyridine-containing metal-organic frameworks as precursor for nitrogen-doped porous carbons with high-performance capacitive behavior

A novel pyridine-containing metal-organic framework (MOF, [Zn(bpdc)DMA]·DMF, bpdc = 2,2′-bipyridine-5,5′-dicarboxylate) was directly carbonized at different temperature to produce nitrogen-doped porous carbons (NPCs). The as-prepared porous carbons, NPC800 (obtained at 800 °C) and NPC1000 (obtained at 1000 °C), were characterized by scanning electron microscopy, X-ray powder diffraction, N2 sorption isotherms, and X-ray photoelectron spectroscopy (XPS). The results from elemental analysis and XPS confirmed that the pyridine groups in MOF served as nitrogen sources to produce NPCs, and NPC800 possessed the higher nitrogen content than NPC1000. N2 sorption data demonstrated that NPC800 exhibited the larger specific surface area and pore volume than NPC1000. The capacitive properties of NPC800 and NPC1000 were investigated in KOH aqueous electrolyte by cyclic voltammetry and galvanostatic charge–discharge curves. NPC800 showed the higher specific capacitance (226.6 F g−1 at 1 A g−1) than NPC1000 and retained 178.0 F g−1 even at a high current density up to 10 A g−1. It was found that the donation of N species to capacitance was more than the role of porosity in view of their synergetic effect.