The Influence of different experimental parameters on Pd based chemical vapor deposition growncarbon nanostructures

Abstract: Carbon nanostructures were fabricated by catalytic decomposition of acetylene ondifferently shaped palladium (Pd) nanocatalysts (nanoplates (triangle/hexagonal) andnanocubes) synthesized by an aqueous solution technique. The fabricated carbonnanostructures were investigated by transmission electron microscopy (TEM), itconsists of multi-walled carbon nanotubes (MWCNTs) together with significant numberof helical carbon nanofibers (HCNFs) and straight carbon nanofibers (SCNFs). Thecontributions of the three major components were highly dependent on the morphologyof nanocatalysts, supportive gas ammonia, substrates and on the growth temperatures.Pd nanocatalysts shows structural sensitivity, the nanostructures synthesized on Pdnanoplates at 550 °C have almost the same amount of MWCNTs and carbon nanofibers(CNFs). At 650 °C the fabricated nanostructures on Pd nanoplates consist of more than95% MWCNTs. The yield and average diameter of all the three components increaseswith rising growth temperature (550-700 °C) and the growth seized completely at 750°C. Ammonia supports the growth of MWCNTs. As the nanocatalysts particles areembedded in the centre of the grown nanostructures; this suggests two directionalgrowths for CNFs.