Diameter-Sensitive Breakdown of Single-Walled Carbon Nanotubes upon KOH Activation
Jianglin Ye1, Shuilin Wu1, Kun Ni1
1Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences and Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, P.R. China.
Abstract:
While potassium hydroxide (KOH) activation has been used to create pores in carbon nanotubes (CNTs) for improved energy-storage performance, the KOH activation mechanism of CNTs has been rarely investigated. In this work, the reaction between single-walled CNTs (SWCNTs) and KOH is studied in situ by thermogravimetric analysis coupled to infrared (IR) spectroscopy and gas chromatography/mass spectrometry (MS). The IR and MS results clearly demonstrate the sequential evolution of CO, hydrocarbons, CO2 , and H2 O in the activation process. By using the radial breathing mode of Raman spectroscopy, a diameter-sensitive selectivity is observed in the reaction between SWCNTs and KOH, leading to a preferential distribution of SWCNTs with diameters larger than 1 nm after activation at 900 °C and a preferential removal of SWCNTs with diameters below 1 nm upon activation.
