Targeted construction of porous biochar with well-developed pore structure for high-performance CO2 adsorption

Targeted construction of porous biochar is vital for the development of carbon capture. In this paper, we use the KOH chemical activation with walnut shell as raw material, to investigate the effects of the preparation process on the targeted construction of CO(2 )adsorbents. We have revealed the vital factors influencing CO2 adsorption and developed the design strategy for porous biochar under different application conditions. The specific surface area can up to 2115 m2 g(-1), and the microporosity can up to 95.5 %. The CO2 adsorption capacities are 6.75 mmol g(-1) and 17.59 mmol g(-1) at 0 degrees C, 1 bar and 10 bar. Meanwhile, the heat of adsorption ranges from 18 to 30 kJ mol(-1). In addition, the sample exhibits outstanding adsorption kinetics, good adsorption selectivity, and its CO2 adsorption capacity fluctuates within 5 % after 10 adsorption-desorption cycles. Therefore, the strategy developed in this paper can be applied to the high-performance adsorption of CO2 under different conditions.