Facile synthesis of nitrogen-doped, hierarchical porous carbons with a high surface area: the activation effect of a nano-ZnO template

Abstract

Hierarchical porous carbons have recently attracted much attention due to their unique features in practical applications, but suffer from the complex and costly synthesis procedure. In this work, a simple but very effective method was proposed to synthesize nitrogen-doped, hierarchical porous carbons with a high surface area by one-step pyrolysis of nano-ZnO/gelatin composites. During pyrolysis, zinc oxide nanoparticles act as not only a hard template to create mesopores, but also an activating agent to create micropores as well as enlarge the pore sizes of the mesopores, making the carbon possess a developed hierarchical porous structure with a high BET surface area of 2412 m² g⁻¹ and a large pore volume of 3.436 cm³ g⁻¹. The activation effect of nano-ZnO was investigated by thermogravimetric analysis, carbon yield, nitrogen adsorption–desorption measurements, SEM, TEM and so on. The pyrolysis temperature has an important influence on the properties of the carbon materials. Both the BET surface area and pore volume increase dramatically with the pyrolysis temperature. Being used as an electrode material for supercapacitors, the developed hierarchical porous structure endows the carbon with superior rate capability.