Partially graphitic, high-surface-area mesoporous carbons from polyacrylonitrile templated by ordered and disordered mesoporous silicas

Ordered and disordered mesoporous carbons synthesized from polyacrylonitrile using a templating method were heated under argon atmosphere at ∼2470 K to partially graphitize them without the loss of mesoporosity. The high-temperature treatment led to a marked enhancement of graphitic ordering, which manifested itself in a narrowing of wide-angle XRD peaks, and in the appearance of domains of lateral dimensions 5–15 nm, consisting of stacked graphitic planes with interplanar spacing of ∼0.34 nm. Raman spectroscopy provided evidence for the increased content of graphitic sp2 carbon structures. The specific surface areas and total pore volumes of the carbons were as high as 500–600 m2 g−1 and 0.8–1.8 cm3 g−1, respectively. These carbons had essentially no microporosity and their surface properties were similar to those of a graphitized carbon black Carbopack X. For ordered mesoporous carbons, the high-temperature treatment led to the loss of nanoscale periodicity, broadening of the pore size distribution (PSD) and ∼40% decrease in the mesopore volume. In contrast, PSD and total pore volume of the disordered carbon were essentially unchanged. These results show that the high-temperature treatment of mesoporous carbons from PAN affords partially graphitic carbons with high specific surface areas and large pore volumes.