FORMATION OF MESOPORES IN PHENOLIC RESIN-DERIVED CARBON-FIBER BY CATALYTIC ACTIVATION USING COBALT

Preparation of an activated carbon fiber containing mesopores was attempted by catalytic activation using cobalt. Phenolic resin and cobalt-acetylacetonate were mixed intimately, spun, cured, carbonized at 900 degrees C in nitrogen and finally activated at 750-900 degrees C in steam. The carbon fibers with the cobalt contents of 38 ppm and 100 ppm were prepared together with a fiber without cobalt as a reference. The cobalt deposited a characteristic turbostratic carbon by catalytic graphitization at carbonization process. Simultaneously the cobalt accelerated activation of the fiber in steam catalytically to form mesopores preferentially. The maximum surface area, 170 m(2)g(-1), for mesopores of several 10s of nm in radius was obtained in the fiber containing 38 ppm cobalt after 38% burn-off. This fiber also contained a relatively large amount of micropores. No damage on the fiber surface after activation was observed by scanning electron microscopy, but the fiber became fragile. The formation mechanism of mesopores is discussed briefly.