Facile synthesis and supercapacitor performances of nitrogen doped CNTs grown over mesoporous Fe/SBA-15 catalyst

Abstract

Herein, we report a new strategy to synthesize high-yield nitrogen-doped carbon nanotubes (NCNTs) using iron-supported SBA-15 as a catalyst via the chemical vapour deposition (CVD) method to utilize them as an electrode material for supercapacitors. A group of Fe/SBA-15 catalysts with different weight percentages of iron (2, 4, 6, 8, and 10 wt%) was prepared and optimized for producing high yield (280%) of NCNTs. Consequently, a series of NCNTs was synthesized by varying the synthesis temperatures from 700 to 1000 °C using an optimized Fe/SBA-15 catalyst. Moreover, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge (GCD) were conducted to evaluate the electrochemical behaviour of NCNTs in a 1 M H₂SO₄ solution. Significantly, the NCNT synthesized at low temperatures possessed a higher nitrogen content of about 2.24 at% and provided a high specific capacitance of 295 F g⁻¹ at a current density of 0.5 A g⁻¹. The results revealed that the NCNT grown over 6 wt% Fe/SBA-15 at 700 °C could be a suitable candidate for high-performance supercapacitors.