Nano-CaCO₃as template for preparation of disordered large mesoporous carbon with hierarchical porosities

Abstract

A series of large mesoporous carbons (LMC, 20-50 nm) with hierarchical porosities has been prepared using commercially available CaCO 3 nanoparticles as a template, formaldehyde (PF) resin as carbon precursor, and HCl solution for removing the template. During the carbonization process, the CaCO 3 template decomposes releasing CO 2 which serves as an activating agent to active the carbon materials producing micropores and mesopores as well as enlarging pore sizes. This effect can be named as the ''CO 2 inner-activation effect'', which is proved by comparing the carbon yield, N 2 adsorption/ desorption isotherms, pore-size distribution and textual parameters of carbon materials carbonized at two critical temperatures, namely, 900 C (higher than the pyrolysis temperature of CaCO 3 ) and 650 C (lower than the pyrolysis temperature of CaCO 3 ). Our results show that the LMC samples prepared at different ratios of CaCO 3 to PF have BET surface areas ranging from 503 to 1215 m 2 g À1 , and pore volumes ranging from 1.8 to 9.0 cm 3 g À1 . This one-step carbonization method with a CO 2 inneractivation effect provides a novel route to prepare large mesoporous carbons and hierarchical porous carbon materials.

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