Hierarchical Nitrogen Nanoporous Carbons by Surfactant-Assisted Synthesis of Zeolitic-Imidazolate Frameworks for High Performance Supercapacitor

Abstract

Nitrogen-doped porous carbons (NPCs) derived from zeolitic imidazolate frameworks (ZIFs) are promising in a wide variety of applications, especially in electrochemical energy storage applications, due to their outstanding physical and chemical properties. Herein, the effect of different types of surfactants as capping agents on the morphology and surface activity of ZIF-derived NPCs was investigated. A series of NPCs were prepared by direct carbonization of ZIF-8 under an inert atmosphere in the presence of capping agents. MOF-derived NPCs with capping agents exhibited accessible pore aperture and relatively high nitrogen content. This affects the textural characteristics of NPCs in terms of morphology, particle size, and surface activity. All the samples were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray diffraction (XRD) technique. The influence of variation of specific surface area of ZIF-8-derived NPCs on its electrochemical properties was investigated. Additionally, the surface charge of the various samples was estimated by point of zero charges (pH PZC ) to find the optimal processing parameters and enhance the capacitive properties. The estimated experimental results showed the optimum results obtained by a higher specific surface areas NPCs prepared with the present of SDS as capping agent with specific surface area 967.5 m 2 /g and larger pore volume 0.78 cm 3 /g, the point of zero charge 7.94 and the specific capacitance in 1.0 M H 2 SO 4 is 490.96 F/g.