Multifunctional nanoporous biocarbon derived from ginger: a promising material for CO₂ capture and supercapacitor

Nanoporous activated carbons derived from bio-waste are gaining consideration due to their exceptional potential for energy storage and CO₂ adsorption. Herein, we put forward a straightforward, low-cost method for preparing a highly efficient nanoporous biocarbon from ginger using solid-state activation approach. Ginger was pyrolyzed at various temperatures before activating using different amounts of KOH as an activator to produce nanoporous biocarbon. The prepared samples possess high specific surface areas and large pore volumes. By simply adjusting the pyrolysis temperature, the microporosity and surface oxygen functionalities can be finely tuned. The best sample exhibits a high Brunauer-Emmett-Teller-specific surface area of 2,330 m²/g and a large pore volume of 1.10 cm³/g and offers excellent specific capacitance of 244 and 119 F/g when tested in a three-electrode and two-electrode, at a current density of 0.5 A/g. Additionally, the optimized material demonstrates a high CO₂ uptake capacity of 4.87 mmol/g at ambient pressure and 25.8 mmol/g at 0 °C and 30 bar. These interesting adsorption and energy storage performances of the nanoporous biocarbon underscore the potential of converting food waste into high-performance CO₂ adsorbents and supercapacitors.