(361d) Catalytic CVD Growth of Millimeter-Tall, Single-Wall Carbon Nanotube Carpets Using Industrial Gaseous Waste As a Feedstock

We have utilized a gaseous product mixture from
Fischer-Tropsch synthesis (FTS-GP) as an efficient feedstock for growth of
high-quality, well-aligned, single-wall carbon nanotube (SWCNT) carpets of
millimeter-scale heights on Fe and (sub) millimeter-scale heights on Co
catalysts via chemical vapor deposition (CVD). Growth conducted at optimal
temperatures for Co (850°C) and Fe (750°C) yielded predominantly SWCNTs that
are straight and clean, with sidewalls largely free of amorphous carbon. Growth
on Fe is characterized by a relatively high growth rate (~50 μm/min) and
long catalyst lifetime (> 90 min), with the catalyst showing no decay of
activity, while growth on a Co catalyst shows a lifetime of ~60 min, with a
slower growth rate of ~7μm/min. Resulting area densities of SWCNT carpets
grown on Fe and Co catalysts, determined by the weight-gain method, were 1.0 ×
10¹² and 6.0 × 10¹² cm^-2, respectively — among
the highest achieved for SWCNT carpets on standard catalysts. Unlike SWCNT
carpet growth involving conventional feedstocks, growth rate and density of
SWCNTs on Fe are less sensitive to the FTS-GP fraction and thus allow for
relatively easy optimization and scale-up.