Fabrication of Hierarchical Macroporous/Mesoporous Carbons via the Dual-Template Method and the Restriction Effect of Hard Template on Shrinkage of Mesoporous Polymers

Abstract

A series of hierarchically ordered macro-<b>/</b>mesoporous polymer resins and macro-<b>/</b>mesoporous carbon monoliths were synthesized using SiO₂ opal as a hard template for the macropore, amphiphilic triblock copolymer PEO–PPO–PEO as a soft template for the mesopore, and phenolic resin as a precursor for the polymer or carbon. The obtained hierarchical macro-<b>/</b>mesoporous frameworks had highly periodic arrays of uniform macropores that were surrounded by walls containing the mesoporous structures. The mesoporous structure of the walls was adjusted using different precursors for the synthesis of FDU-14, FDU-15, and FDU-16. Results of the N₂ adsorption–desorption analysis showed that the Brunauer–Emmett–Teller surface areas, the pore volumes, and the mesopore sizes of the macro-<b>/</b>mesoporous carbons were much larger than those of the FDU-14, FDU-15, and FDU-16 carbon materials. The mesopore size of the samples clearly increased with the increasing heat-treatment temperature when the temperature was below 700 °C. The results indicate that the SiO₂ hard template successfully restricted the shrinkage of the framework during the thermosetting and carbonization process