Solid-Phase Debundling of Single-Walled Carbon Nanotubes for the “Stock Solid” Delivery of Concentrated Nanotube Dispersions

Abstract

Debundling of single-walled carbon nanotubes (SWNTs) has been mostly limited to liquid-phase exfoliation. Since the SWNTs in dispersion are prone to aggregate and precipitate gradually during their storage, a solid-phase method that provides debundled SWNTs as "stock solid" is highly required. Herein, we report on a solution to this issue, which is based on solid-phase ball milling. The milled solid, composed of debundled SWNTs and surfactant, can be stored as "stock solid" and is readily dispersed in water just by shaking with hand, giving concentrated SWNTs dispersion (up to 1.16 mg/mL) with yield up to 60% after centrifugation.

Fabricating 0D/1D/2D Ag/Carbon Nanotube/WS2 Heterostructure for Boosted Hydrogen Evolution Reaction in Akaline and Acidic Conditions

“…In the Raman spectra shown in Figure b, both samples exhibit two decent peaks at 1350 and 1580 cm –1 , corresponding to the D band (related to the disorder of the CNT sidewalls) and G band (related to the vibration of the graphitic carbon) of the CNT, respectively. The peak intensity ratio of the D band to G band ( I D / I G ) can reflect the defect ratio; the higher the I D / I G value, the higher the defect ratio of the sample . As shown in Figure b, both samples show relatively high I D / I G values (0.98–1.04), indicating a high −COOH content of the carboxylated CNTs, which is beneficial to the wettability of the composites as well as the uniform distribution of the AgNPs in the CNT matrix.…”

“…The peak intensity ratio of the D band to G band (I D /I G ) can reflect the defect ratio; the higher the I D /I G value, the higher the defect ratio of the sample. 20 As shown in Figure 3b, both samples show relatively high I D /I G values (0.98−1.04), indicating a high −COOH content of the carboxylated CNTs, which is beneficial to the wettability of the composites as well as the uniform distribution of the AgNPs in the CNT matrix. With the incorporation of WS 2 , peaks corresponding to the 1T and 2H phases of WS 2 newly appear in the range of 150−500 cm −1 for Ag/MCNT/WS 2 (Figure 3b).…”

“…Debundling of MCNT was achieved through a solid-phase exfoliation approach reported previously. 20 Briefly, 60 mg of carboxylated MCNT and 120 mg of SC were placed in equal amounts in two ball-milling tanks and were ball-milled at 200 rpm for 3 h. The resulting black powder was dispersed in deionized water and centrifuged at 8000 rpm for 30 min to remove the unexfoliated MCNT bundles. The supernatant was dialyzed against deionized water for 48 h and then freeze-dried to provide debundled MCNT powder as "stock solid" for further usage.…”