High-efficient and environmentally friendly enrichment of semiconducting single-walled carbon nanotubes by combining short-time electrochemical pre-oxidation and combustion

Abstract High purity semiconducting single-walled carbon nanotubes (s-SWCNTs) have bright prospects in the field of microelectronics, but their enrichment processes are usually very complicated and cost time and energy, which represent a major impediment for their future applications. Here, we report on a new efficient covalent modification enrichment approach that tackles this problem. Our method is to first selectively functionalize the surface of arc-discharge metallic single-walled carbon nanotubes (m-SWCNTs) rapidly by electrochemical pre-oxidation at 7.0 V in 0.1 M KCl aqueous solution, and subsequently followed up by removing the m-SWCNTs with a short-time combustion process at 600 °C for 30 s to enrich high purity s-SWCNTs. Although the surface of the s-SWCNTs was functionalized and heat-treated, the intrinsic tubular structure and electronic characteristics were well maintained. Besides, our approach, without any complex equipment or toxic reagents, is energy and time saving and can be easily scaled up. Milligrams of high-quality s-SWCNTs with high purity of more than 95 wt% can be easily obtained in only several minutes. The retention rate of s-SWCNTs after combustion is as high as 61 wt%.