Gigas Growth of Carbon Nanotubes

An exceptionally high yield of carbon nanotubes (CNTs) has been achieved by chemical vapour deposition (CVD) of camphor over zeolite support. A simple 30 min CVD of 12 g camphor over Fe-Co-impregnated zeolite at 650°C in an academic laboratory setup, yields 6 g multiwalled CNTs of dia ∼10 nm with an as-grown purity of ∼88 per cent. Owing to the enormous CNT growth, the zeolite bed inflates by 1000 wt per cent and 10,000 vol per cent. Camphor-to-CNT production efficiency is 50 per cent and net carbon-to-CNT conversion efficiency is 61 percent. These figures are incomparably higher than that of any CNT precursor by any method. Hence it is called ‘gigas growth’. The technique greatly complies with the principles of green chemistry, and thus sets an example of an environment-friendly nanotechnology.