Diameter-control in synthesis of carbon nanotubes inside porous stainless steel block and application to glucose fuel cell electrode

Carbon nanotubes (CNTs) can be synthesized on inner surface of a porous stainless steel block by feeding ethanol or methanol as carbon source. In comparison with a conventional CNT growth in the porous stainless steel block by feeding ethylene, the diameter of CNTs in the newly-developed conditions using the alcohols are significantly smaller. In these conditions, a radial breathing mode were observed in Raman spectra, indicating the presence of single-walled carbon nanotubes. When the porous stainless steel block including CNTs directly grown on its inner surface is used for an anode in a glucose fuel cell, its power generation using the new CNT growth condition with ethanol or methanol can be improved by approximately three times higher than using the conventional condition with ethylene. Compared with the two alcohols used here, the fuel cell using the anode with the CNTs synthesized from methanol can exhibit 10% higher power than that from ethanol. According to Raman shift analysis and TEM observation, the surface area and the crystallinity of CNTs seem to be the key factors to realize the high electric generation performance.