CoMoCAT-SWNTs

In a hypothetical CCVD process similar to CoMoCAT, SWNT are produced in a fluidized bed reactor by disproportionation of carbon monoxide (2CO C + CO2). Fresh catalyst is added at a continuous rate (CTl) of 10 kg/h. Before puri-Acation, the black sand product (CT2) contains 30 wt% carbon, while the rest of... 

One of the most successful examples is chromatographic separation of SWNTs wrapped with DNA [136,137,139,140]. Quite recently, (6,4), (9,1) and (6,5) SWNTs were obtained in almost pure form by sorting of CoMoCAT SWNTs wrapped with DNA with conventional ion-exchange chromatography [33]. The SWNTs/DNA solution was subjected to a variety of optical analyses such as circular dichroism, photoluminescence and absorption spectroscopies [141-143] as well as investigation of their photo- and electrochem-icalbehaviors [144,145]. The strong interaction between SWNT and DNA was simulated theoretically by molecular dynamics [146] and ab initio calculations [147], and used for nanofabrication of SWNTs [148,149]. 

Figure 6.60. Illustration of two methods used for the commercial production of SWNTs. Shown are (a) the CoMoCat fluidized bed method using CO as the precursor and a Co/Mo bimetallic catalyst,[84] and (b) the HiPco floating catalyst process using the thermal decomposition of iron pentacarbonyl at pressures of 1-10 atm.[85]...

Figure 13.8 Schematic drawings for the different SWNT synthesis methods, (a) Arc discharge (dc). Nanotuhes are collected from the cathode surfaces (indicated hy A) and from the inner wall of the evaporator (indicated hy B). (h) Laser vaporization. The C/Ni/Co target is positioned inside a furnace. The carbon and catalyst vaporization is reaUzed by irradiation with a double laser, in this case, a XeCl and a NdYAG. (c) Fluidized bed CCVD reaction system used in the CoMoCAT process. [Part (a) reproduced with permission from Y. Saito et al, J. Phys. Chem. B 2000, 104, 2495. Part (b) reproduced with permission from A. A. Puietzky et al, Appl. Phys. Lett. 2000, 76, 182.]...

One important aspect in the SWNT production by CCVD method is the reactor design. Large-scale production requires reactor designs amenable to being scaled up. An example of a schematic design is shown in Figure 13.8c for the fluidized bed system employed in the CoMoCAT process. 

CoMoCAT (fluidized-bed CVD) and HiPCO (high-pressure CO CVD), have recently been developed for the commercial production of SWNTs (Figure 6.79). Though the experimental setup of these methods are significantly more complex than standard hot-walled CVD, these techniques are still considered an extension of... 

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