Self-template biomass-derived nitrogen and oxygen co-doped porous carbon for symmetrical supercapacitor and dye adsorption

Exploring high-efficiency, green, low-cost, and sustainable biomass waste materials to solve energy shortage and environmental contamination issues is still a significant challenge. Herein, self-template corncob porous carbon (CPC) with bifunctions, high oxygen (16.34 at%), and nitrogen content (2.30 at%) was obtained by a simple carbonization-activation method. Benefiting from the high specific surface area, porous structure and high oxygen and nitrogen content of the prepared CPC, the optimal CPC-700-2 exhibited a higher special capacitance of 295.93 F g–1 at the current density of 1 A g–1, good rate capability (170 F g–1 at 50 A g–1), and excellent stability and circularity. Significantly, the CPC-based symmetric supercapacitor demonstrated a high energy density (9.9 Wh kg−1) at a power density of 250 W kg−1, and exceptional cyclic stability. More interestingly, the CPC also has an efficient sewage purification capacity. The adsorption test confirmed that the CPC possesses a higher adsorption capacity and removal rate for Rh B (249.06 mg g–1 and 99.87%). This satisfactory performance provides a potential way for the high value-added utilization of agricultural and forestry waste.