Communication—Self-Doped Mesoporous Activated Carbon Prepared from Car Exhaust Exhibited Long Cycle Life and High Specific Capacitance for Supercapacitor Applications

We are reporting the preparation of a self-doped mesoporous activated carbon by the treatment of waste collected from car engine exhaust. The waste was pyrolyzed at 850°C in N ₂ atmosphere using KOH activating agent. Highly porous activated carbon was obtained with the presence of N, O, S, and P as self-dopant. A high specific surface area of 410 m ² g ⁻¹ with the pore volume of 0.5947 cm ³ g ⁻¹ was achieved. Electrode prepared with the activated carbon showed a high specific capacitance (280 Fg ⁻¹ ) using a 1-butyl-3-methylimidazolium chloride electrolyte. It retained 95% of initial capacitance after 10,000 cycles, demonstrated high cyclic stability and sustainability.