Facile One‐Pot Synthesis of Activated Porous Biocarbons with a High Nitrogen Content for CO₂ Capture

Abstract A facile one‐pot synthesis of porous activated biocarbons with a high nitrogen content (NEPBs) through a simple in‐situ self‐assembly of Arundo donax and urea combined with a solid state activation using KOH/ZnCl₂ is presented. NEPBs show dominant microporous character and possess a high nitrogen content in the form of pyridinic‐N and pyrrolic‐N and a high specific surface area. The nitrogen content of NEPBs was determined to be in the range of 7.74–19.15%, which was much higher than that of biocarbon derived from non‐activated biomass (1.12%). We also demonstrate that the nitrogen content of NEPBs can easily be tuned by adjusting the impregnation ratios of urea and KOH/ZnCl₂. The NEPBs show impressively high CO₂ adsorption capacities of 4.8 mmol g⁻¹ at 0 °C/1 bar and 14.1 mmol g⁻¹ at 0 °C/30 bar. A high value of the isosteric heat of adsorption is observed (39 kJ mol⁻¹), confirming the role of nitrogen to enhance the CO₂ adsorption capacities through a strong adsorbent‐adsorbate interaction. It is anticipated that the strategy presented here could be extended for the generation of a series of other biomass‐based porous carbon materials with much higher nitrogen contents and controlled textural properties for applications including energy storage and conversion and carbon capture.