Synthesis of carbon nanostructured materials using LPG

Abstract

Chemical vapour deposition (CVD) was applied using liquid petroleum gas (LPG) as the carbon source as a rapid and simple route to prepare ordered mesoporous carbon (OMC) as well as carbon nanotubes (CNT). The OMC product prepared using the CVD technique was an intricately connected network of covalently bonded graphitic carbon material with periodic pores in the mesoporous size regime. The mesoporous ordering was derived from a silica based mesoporous precursor hexagonal mesoporous silica (HMS) that provided control over porosity of the final OMC. Thus LPG infiltrated the mesoporous silica template, and thermally decomposed to form a structurally robust, ordered mesoporous carbon material analogous to HMS after removal of the silica template. The resulting OMC had regular 3–4 nm sized pores, as confirmed by low angle XRD. Carbon nanotubes grown using the LPG CVD technique gave good yields on a nickel porous membrane. Differences observed between Ni porous membranes compared with Ni and Co foils as catalytic surfaces was attributed to the structure of the Ni porous membranes, with micrometer-sized Ni oxide particles fused into a highly porous structure creating a larger surface area for the diffusion of carbon into the Ni, and subsequent precipitation of carbon for the formation of CNTs. When metal foil surfaces were altered through electroless deposition the yield of nanotubes increased significantly using LPG CVD. Ni catalysts in the LPG CVD system for the growth of CNTs, produces nanotubes with more crystalline features than those produced by Co. The LPG CVD technique is demonstrated to be a rapid and simple route to prepare nanostructured and graphitic carbons, OMC and CNT.