Catalytic graphitization of polyacrylonitrile-based carbon fibers coated with Prussian blue

Prussian blue (PB) was used as catalyst to improve the extent of graphitization of polyacrylonitrile (PAN)-based carbon fibers. PB was deposited on carbon fibers by anodic electrodeposition and the thickness of PB coating (PB content) was controlled by adjusting the electrodeposition time. PAN-based carbon fibers with PB coating were heat-treated and the extent of graphitization was measured by X-ray diffractometry and Raman spectroscopy. The results indicate that the extent of graphitization of PAN-based carbon fibers is enhanced in the presence of the coating. When the PB-coated carbon fibers were heat-treated at 1 900 °C, interlayer spacing (d 002) and crystallite size (L c) reach 0.336 8 and 21.2 nm respectively. Contrarily, the values of d 002 and L c are 0.341 4 and 7.4 nm respectively when the bare carbon fibers were heat-treated at 2 800 °C. Compared with the bare carbon fibers, PB can make the heat treatment temperature (HTT) drop more than 500 °C in order to reach the same extent of graphitization. Furthermore, the research results show that PB content also has a certain influence on the extent of graphitization at the same HTT.