Single- and multi-wall carbon nanotubes produced using the floating catalyst method: Synthesis, purification and hydrogen up-take

The floating catalyst (FC) method for synthesis of single- and multi-wall carbon nanotubes was optimized and scaled up to yield 6 g/h and 20 g/h of products, respectively. Different CNTs purification methods were compared. It was found that the procedure involving room temperature bromination is the most effective to purify the FC-CNTs. The hydrogen up-take capacities of the different products were measured using the quasi-equilibrium volumetric method. It was shown that, at room temperature and gas pressure up to 150 atm for both SWCNTs and MWCNTs, hydrogen up-take does not exceed 1.5 wt.% and is weakly dependent on the product purity.