Water chestnut shell-derived N/S-doped porous carbons and their applications in CO2 adsorption and supercapacitor

Porous carbons have attracted great interest in both CO2 capture and supercapacitor applications owing to their unique textural, physicochemical and electrochemical properties. Fabrication of eco-friendly and cost-effective heteroatom-doped porous carbons from renewable biomass resources becomes a sustainable route for future carbon capture and energy storage technology. Herein, for the first time, N/S-doped porous carbon has been prepared via the KOH-activating method using water chestnut shell as a carbon precursor and thiourea as nitrogen/sulfur source. The as-prepared carbons possess a well-developed porosity and excessive nitrogen/sulfur functionality. These porous carbons were examined as absorbents for CO2 uptake and as electrode materials for supercapacitors. The maximum CO2 uptake for these carbons is up to 4.54 and 6.90 mmol g−1 at 25 and 0 °C and 1 bar, respectively, thanks to the high nitrogen/sulfur functional groups and advanced porosity. Besides, this series of carbons presents outstanding performance as electrode material not only with a high specific capacitance of 318F g−1 at a current density of 0.5 A g−1 but also superior cycling durability of 94 % retention after 5000 cycles. Last but not least, we in-depth enlighten the potential reasons behind the high performance of CO2 uptake and supercapacitor application. The present study suggest that water chestnut shell-derived porous carbons may become a strong candidate in both CO2 adsorption and supercapacitor fields.