Figure 4
Experimental and theoretical investigations of the effect of catalyst pretreatment on SWNTs growth: Cap nucleation state. (a) Atomistic configuration of graphene and Co(0001) surface with and without oxygen atoms interacted by top(hcp) orientation. Blue and yellow spheres represent cobalt atoms in A and B layers, respectively, and gray and red ones represent carbon and oxygen atoms. Graphene in the system with oxygen atoms is not shown for the clarity of the image. (b) Binding energy per carbon atom between graphene and Co(0001) surface with and without oxygen atoms for top(hcp) orientation as a function of interlayer distance. (c) Total binding energy per each cap as a function of total number of carbon atoms in each cap (∝ d) for Co (red) and CoOx (blue) catalyst. (d) Experimental data of normalized PL intensity as a function of d of SWNTs grown from zeolite-supported Co without (blue) and with (red) pretreatment.
