Direct transformation of ZIF-8 into hollow porous carbons and hollow carbon composites

Hollow porous carbons (HPCs) are a class of porous materials with advantages of high surface to volume ratio, large interior cavities, low density, and short diffusion length, which are promising in various applications. Direct carbonization of carbon precursors is the simplest and the most cost-effective method to prepare porous carbons, however, it often leads to non-hollow structures. Herein, we demonstrate the preparation of HPCs through a direct carbonization method with a two-step heating process of zeolitic imidazolate framework-8 (ZIF-8) and tetrafluoroterephthalonitrile (TFTPN). During the carbonization, ZIF-8 nanoparticles first react with TFTPN at low temperature to create polymer coatings on the surface, which are then converted into HPCs at elevated temperature. The obtained HPCs show hierarchically porous structure with high specific surface areas and pore volumes. Additionally, this method has been adopted to fabricate Au@HPCs yolk-shell composites, exhibiting good catalytic performance in nitrobenzene reduction. The developed synthesis strategy can enrich the toolbox for the preparation of novel HPCs and their composites.