Synthesis and protium absorbing properties of vapor grown carbon nano-fibers grown by Fe-based catalyst

Vapor grown carbon nano-fibers (VGCFs) were synthesized by using Fe ingots, Fe powders, nanocrystalline Fe₉₁Zr₇B₂ and Fe₇₅Si₁₅B₁₀ alloy catalysts with fine bcc-Fe grains (∼ 20 nm). The Fe particles worked as catalysts were formed by fracturing original Fe ingots, Fe powders, and nanocrystalline alloys before the formation of VGCFs. TEM and HREM observations indicated that VGCFs' structures turned out to be platelet type grown from Fe powders and Fe₉₁Zr₇B₂, and the tubular type grown from nanocrystalline Fe₇₅ Si₁₅B₁₀ alloy. In addition to these structures, VGCFs grown from Fe ingots exhibited herringbone and coil type structures. Diameter of VGCFs prepared from nanocrystalline Fe₇₅Si₁₅B₁₀ alloy was smaller than that of grown from Fe₉₁Zr₇B₂ alloy. This could be originated from the difference of fracturing process between nanocrystalline Fe₉₁ Zr₇ B₂ and Fe₇₅ Si₁₅ B₁₀ alloys. Protium absorbing properties of VGCFs were evaluated by a Siverts-type apparatus and electrochemical method. It turned out that VGCFs had little protium absorbing capacity.