Highly crystalline graphite-like carbon from wood via low-temperature catalytic graphitization

In this study, we investigated the synthesis of wood-sawdust-derived high-crystalline graphite-like carbon. The sawdust was first impregnated with Fe and semi-carbonized by a hydrothermal treatment (HT) at 250°C, followed by the second carbonization under N₂ atmosphere and acid washing. For an iron-to-sawdust weight ratio of 4:10, graphite-like carbon was synthesized at a very low temperature of 850°C. This carbon has an average interlayer distance and crystallite size (d₀₀₂: 0.337 nm, La: 35.8 nm, and Lc: 56.1 nm) comparable to those of commercial graphite. The large size of the Fe crystal particles facilitates the development of a stacked structure of carbon sheets. The HT with Fe-impregnated sawdust generates larger iron oxide particles than simple semi-carbonization with Fe-impregnated sawdust under N₂ atmosphere at 250°C, facilitating the development of more crystalline graphite-like carbon. It was also found that the crystallinity of the graphitic carbon obtained after second carbonization may be controlled by the amount and particle size of the added Fe.