Template carbon onions

Gu, W., and G. Yushin. 2014. Review of nanostructured carbon materials for electrochemical capacitor applications Advantages and limitations of activated carbon, carbide-derived carbon, zeolite-templated carbon, carbon aerogels, carbon nanotubes, onion-Uke carbon, and graphene. Wiley Interdisciplinary Reviews Energy and Environment 3 424-473. 

A novel template effect of SiNWs tvas discovered accidentally trying to disperse SiNWs in common solvents such as CHCI3, CH2CI2 and CH3I. A 15 min bath sonication resulted in a colloidal solution, the products of which were characterized by HRTEM, EELS and Raman. The analysis revealed that under sonication the SiNWs acted as templates on which carbon nanotubes and carbon nano-onions formed (figure 10.32). Moreover, in addition to these known carbon structures. 

Fig. 10.33. High magnifications of (a) carbon nanotube and (b) carbon nano-onion grown on the SiNW template...

Another method to generate onion-hke structures (besides nanotubes and irregular carbon particles) is the ultrasonication of chloroform, dichloromethane, or similar solvents containing halogens. The decomposition of the solvent takes place on hydrogen-terminated sihcon nanowires which, at the same time, also serve as a template to the formation of tubular structures. 

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