Catalytic Synthesis And Supercapacitor Performance Of Carbon Nanotubes (Fibers) Cloth Using Nanoporous Copper Catalyst

Carbon nano-materiales, including carbon nanotubes (CNTs) and carbonnanofibers (CNFs), have attracted much attention for their applications aswave-asorbing materials, electrode materials, and conductive enforcements etc, due totheir unique nano-size effect, large specific surface area and good electricalconductivity. The catalysts used most widely for the synthesizing the carbonnanomaterials are the composite system supported with metal nanoparticles composite,but it is hard to guarantee the uniformity of the product structure due to the complexpreparation process. The agglomeration of metal nanoparticles in catalytic processcauses easily the catalyst deactivation. Herein, it is very important to explore a newunsupported nanometal catalyst system for the carbon nanomaterial’s application.Firstly, nanoporous copper (NPC) with the3D continuous and uniform structurewas fabricated by a simple dealloying method using Cu30Mn70stripe. Then, CNTsand CNFs clothes were synthesized with one-step using the NPC based catalystwithout any supporters for the first time. The effect of the processing parameters, suchas the preparation and composition of the catalyst, reduction and reactiontemperatures and carbon sources on the production morphologies, was systematicallyinvestigated. The carbon nanomaterials obtained were directly used as thesupercapacitor electrode and the effect of the surface functionalization of CNTs andCNFs on their electrochemical performance was also discussed in detail.The results show that:1) Carbon nanomaterials were successfully synthesized byCVD method with one-step using NPC based catalyst, exhibiting highly catalyticproperty without the influence of substrate and the agglomeration of metalnanoparticles. The bamboo-shaped CNTs with diameter of40nm, high purity andyield were directly obtained using NPC as catalyst, while the single helical CNFs withspiral diameter of100nm were prepared using Ni/Y/NPC as the catalyst at the samesynthesis condition. The yield of carbon product was reached up to240%.2) Thespecific surface areas of both CNTs and CNFs were significantly increased bypurification, plasma treatment and activation treatment. The amount of surfacefunctional groups (-OH) and (-NO2) of CNTs are increased by nitric acid activation.The CNFs have more surface functional groups (C≡N) and CO2absorption by nitric acid activation compared with the CNFs untreated.3) The bamboo-shaped CNTs andhelical CNFs were directly used as the supercapacitor electrode without any binders,current collectors and carriers, showing excellent electrochemical properties. Thespecific capacitances of bamboo-shaped CNTs, activated by plasma and nitric acid,are respectively two times and six times higherthan that of the untreated CNTsrespectively. Helical CNFs show similar behavior. A high specific capacitance of75.93F/g was obtained for the acid-treated CNFs at a current density of300mA/g,which is fifteen times higher than that of the untreated CNFs.