Facile synthesis of hierarchical N-doped hollow porous carbon whiskers with ultrahigh surface area 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 3 whiskers as a green template and double inner-activating agent. Two inner activators, CO 2 and Ca(OH) 2 , are generated from the CaCO 3 whisker template during the carbonization process. Among them, Ca(OH) 2 was formed by H 2 O vapors reacting with the remaining template CaO. Attributed to the drastic synergistic effect of inner-activation (CO 2 or Ca(OH) 2 ) and outer-activation (KOH), the synthesized HPCWs exhibit ultrahigh SSA (3007 m 2 g −1 ), the largest pore volume (2.63 cm 3 g −1 ) and a controllable proportion of micropores ( S m / S t , 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 −1 ), which is two orders of magnitude (10 2 ) 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. Facile synthesis of hierarchical N-doped hollow porous carbon whiskers with ultrahigh SSA via synergistic inner-outer activation for casein hydrolysate adsorption.