Macroporous Activated Carbon Fibers from Rayon Precursors Impregnated with Phosphoric Acid

Novel activated carbon fibers (ACFs) from rayon precursors impregnated with phosphoric acid (H₃PO₄), containing abundant macropores (pore size>50 nm), were successfully obtained. The physical properties of these ACFs were examined. The BET surface was obtained; SEM observations showed that the concentration of H₃PO₄ impregnation strongly influenced the surface morphology and the porous texture of the resulting ACFs. The shape of the pores was nearly round and we could estimate the pore size was distributed between 20 and 150 nm. Infrared spectroscopy (IR) was applied to investigate the pyrolysis process of the rayon precursors with H₃PO_4. In addition, P‐containing substances, which should perhaps be acid phosphates or polyphosphates, can be observed on the surface of the resulting ACFs from SEM photos. Impregnation made the dehydration become more predominant during the pyrolysis process.

Keywords:

• activated carbon fibers
• macropores
• BET surface area
• SEM
• IR
• TGA

Acknowledgements

The authors acknowledge Zheng Yifan, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Zhejiang University of Technology, for his kind help and assistance. This work was funded both by a grant from the Chinese NSFC (No. 50403005) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.