金属超微粒子による各種炭素材料の触媒化学的エッチング

抄録

This review paper describes the etching behavior of various carbon materials by metal nanoparticles (cobalt, nickel or platinum) in a flowing gas mixture of hydrogen and nitrogen (1 : 9) between 700 °C and 1000 °C based on our earlier studies. This study started from the observation of the etching of a carbon black (CB) by PtCo particles in a PtCo/CB catalyst. In a highly oriented pyrolytic graphite (HOPG) catalytic etching with cobalt nanoparticles produced straight channels on the cleavage planes, usually starting at the edges of the planes, and resulting in the formation of methane by the catalytic reaction of HOPG and hydrogen on the metals. In the case of an activated carbon (AC) cobalt nanoparticles etched the inner region of the AC forming many mesopores and channels with graphite-like walls. A boron-doped diamond electrode, a highly oriented {100} diamond coating and synthetic diamond crystallites were also etched by these metal particles, probably in a semi-molten state. The patterning of the {100} planes of diamond with small etch pits containing metal nanoparticles is promising for the development of functional materials, such as agglomerate-proof metal catalysts or new electronic devices.