Hierarchical porous carbon obtained using the template of NaOH-treated zeolite β and its high performance as supercapacitor

Alkaline-treated zeolite β (AT-β) has been taken as the template to prepare hierarchical porous carbons by a two-step casting process. The structures are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen sorption at 77 K and high-resolution transmission electron microcopy. The electrochemical performances of the supercapacitors tested by cyclic voltammetry and galvanostatic charge–discharge cycling are conducted in both aqueous and organic electrolytes. The carbon samples starting from AT-β (CN1 to CN3) exhibit higher capacitance retentions than the sample started from zeolite β (CN) due to the different pore structures. In aqueous electrolyte, CN2 presents the best electrochemical performance which could be attributed to the highest accessible specific surface area. In organic electrolyte, CN shows the highest capacitance at low scan rate (or current load) consisting with the highest pseudocapacitance contribution of C–O quinone type groups (O-I), pyrrolic/pyridone (N-5) and pyridinic (N-6).