Growth of filamentous carbon by decomposition of ethanol on nickel foam: Influence of synthesis conditions and catalytic nanoparticles on growth yield and mechanism

This paper presents nano-sized carbon filaments grown by catalytic decomposition of ethanol on polycrystalline nickel foam. Our study is focused on the effects of synthesis conditions on the formation of filamentous carbon. The formation rate of filamentous carbon increased as the supply of liquid ethanol into the furnace and the synthesis time increased during growth process, whereas H2 concentration in carrier gas had the opposite effect. The most favorable temperature for the highest formation rate was around 600 °C. We investigated the role of catalytic nanoparticles in the growth mechanism of filamentous carbon. Tip growth was the primary mechanism responsible for growth of the filamentous carbon; octopus-like carbon filaments were formed on large nanoparticles of about 100 nm in diameter. It was also discovered that surface break-up on the nickel foam precipitated the formation of filamentous carbon. We detected the presence of Ni3C as synthesis conditions after a long exposure to ethanol.