Targeting application of hierarchical porous carbon by facile one-step site-specific activation of wood powder: CO2 adsorption and supercapacitors

Optimization of pore parameters for specific applications is crucial for utilization of hierarchical porous carbon (HPC). In this work, we report a facile method to obtain HPCs for targeting applications in a controlled manner by a one-step site-specific activation method with trace amounts of KOH. For CO 2 adsorption applications, the material is optimized to have a pore size consistent with the kinetic diameter of CO 2 , which facilitates the diffusion of CO 2 in the material. The optimized material shows exceptional CO 2 adsorption capacity (5.21 mmol g −1 at 0 °C and 3.54 mmol g −1 at 25 °C), and excellent adsorption reversibility (97.6% at 0 °C and 98.9% at 25 °C). For supercapacitor applications, the pore size of the optimized HPC is multiple of the size of hydrated potassium ions, which enhances the transport of electrolyte ions. The optimized material provides a high specific capacitance of 369 F g −1 at 0.5 A g −1 , and the assembled symmetric supercapacitor exhibits an extraordinary energy density of 30.51 Wh kg −1 at a power density of 92.23 W kg −1 . This work provides new insight into tuning of the pore parameters for specific applications of HPCs, and a facile strategy for value-added utilization of biomass materials.