resumo
Hot-filament chemical vapour deposition (HF-CVD) was used to grow aligned carbon nanofibers (CNFs) directly on Cu foils. Fast wet-chemical etching procedures based on hydrogen peroxide (H2O2) were found to have a key role on the formation of selective active substrates for the growth process. Here, a comprehensive mechanism is presented. Additionally, it is shown that nano-sized protrusions similar to 8 nm with round shape and high density similar to 1.7 x 10(3) mu m(-2) were decisive for the growth of aligned hollow-herringbone CNFs following the base-growth model. CNFs with heights of similar to 1 mu m and diameters around similar to 8 nm show narrow diameter size distribution with remarkable correlation to the protrusion size distribution. The fibers were organised in cone-shape configurations with a cone density of similar to 22 mu m(-2) and a cone angle of 90 degrees. An activation energy for the CNF growth of E-act similar to 0.90 +/- 0.16 eV was extracted from the Arrhenius plot showing that the process kinetics is governed by C diffusion in bulk Cu. (C) 2011 Elsevier Ltd. All rights reserved.
palavras-chave
CHEMICAL-VAPOR-DEPOSITION; CATALYZED DECOMPOSITION; METAL NANOPARTICLES; CU(100) ELECTRODES; AMORPHOUS-CARBON; NANOTUBE GROWTH; ACID-SOLUTION; METHANE; TEMPERATURE; PARTICLES
categoria
Chemistry; Materials Science
autores
Mata, D; Amaral, M; Fernandes, AJS; Oliveira, FJ; Costa, PMFJ; Silva, RF
nossos autores
Diogo Miguel Rodrigues Marinho da Mata
Bolseiro de pós-Doutoramento
Filipe José Alves de Oliveira
Investigador Principal
Rui Ramos Ferreira e Silva
Professor associadoagradecimentos
D. Mata and M. Amaral are very grateful to FCT for the grants SFRH/BD/36273/2007 and SFRH/BDP/26787/2006, respectively.