Facile synthesis of hierarchical N-doped hollow porous carbon whiskers with ultrahigh surface area via synergistic inner-outer activation for casein hydrolysate adsorption

N-doped hollow porous carbon materials have attracted significant scientific interest in the field of peptide adsorption, drug delivery and catalysis. However, their facile synthesis is still a challenge due to the lack of an ideal template and effective route for high specific surface area (SSA). In this work, we report a facile approach for preparing N-doped hollow porous carbon whiskers (HPCWs) by using CaCO whiskers as a green template and double inner-activating agent. Two inner activators, CO and Ca(OH) , are generated from the CaCO whisker template during the carbonization process. Among them, Ca(OH) was formed by H O vapors reacting with the remaining template CaO. Attributed to the drastic synergistic effect of inner-activation (CO or Ca(OH) ) and outer-activation (KOH), the synthesized HPCWs exhibit ultrahigh SSA (3007 m g ), the largest pore volume (2.63 cm g ) and a controllable proportion of micropores (S /S , 60-86%). These intriguing pore structure characteristics of HPCWs endow with them rich target-oriented applications, as exemplified by their outstanding adsorption for casein hydrolysate (10 080 mg g ), which is two orders of magnitude (10 ) higher than that of common porous materials. This facile and green synthesis strategy may pave a new way to prepare hollow porous carbon materials with the desired pore structure and high surface area for numerous applications.