Effect of Starting-Mixture Composition on Morphological Properties and Microstructure of Hierarchical Porous Carbon

A hierarchical porous carbon derived from phenolic resin (PF) was processed using ethylene glycol (EG) and starch as double porogens. The influences of composition of starting mixture, including the two porogens and PF, on morphological properties and microstructure of the porous carbon were investigated. It was demonstrated that the content of starch and the relative content of EG to PF played key roles in determining the number, size and formation of the hierarchical pores, which in turn led to changes in the properties and the microstructure of the porous carbon. In particular, the number of the first-level pores (diameter ~10–40 μm) increased with the content of starch increasing, and the high relative content of EG to PF contributed to the formation of the second-level pores (diameter ~0.5–2 μm), which were closely related to the formation mechanisms of the two-level pores, respectively. Under the present experimental conditions, sufficiently high starch content can result in the microstructural abnormalities, such as the incomplete decomposition of starch and the formation of the third-level pores which originated from the stack of discrete carbon particles.