Chlorinated holey double-walled carbon nanotubes for relative humidity sensors

• Published in: Carbon (New York) Vol. 148; pp. 413 - 420
• Main Authors: Bulusheva, L.G., Sysoev, V.I., Lobiak, E.V., Fedoseeva, Yu.V., Makarova, A.A., Dubois, M., Flahaut, E., Okotrub, A.V.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.07.2019; Elsevier BV
• Subjects: Carbon; Carbon nanotubes; Carbon tetrachloride; Chemical sensors; Chlorination; Chlorine; Density functional theory; Double-walled carbon nanotubes; Holey nanotubes; Humidity; Nanotubes; Organic chemistry; Purging; Relative humidity; Relative humidity sensor; Sensors; Sulfuric acid; Walls; Water chemistry; Double-walled carbon nanotubes; Relative humidity sensor; Holey nanotubes; Chlorination
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2019.04.010

A chemical procedure for modification of double-walled carbon nanotubes (DWCNTs) to enhance their response to humidity was developed. The DWCNTs walls were etched by hot concentrated sulfuric acid, after what the edge carbon sites were saturated by chlorine via reaction with CCl4 vapor. This treatment increases the dispersibility of DWCNTs in solvents, removes oxygen groups, and produces chlorine-decorated holes in the outer walls. Networks of chlorinated holey DWCNTs showed a high repeatable response to humid environment and a good reversible behavior after the sensor purging by dry air. The density functional theory calculations predict enhanced polarization of the DWCNTs when they contain chlorine-decorated holes in the outer walls and physisorption of H2O molecules near chlorine atoms. These two effects are the cause of an intense low-noise signal to gaseous H2O and easy sensor recovery. [Display omitted]