Evolution of single-wall carbon nanotubes during hydrothermal treatment

The evolution of single-wall carbon nanotubes (SWNT) under hydrothermal treatment was investigated. Single-wall carbon nanotubes were used as the starting material and treated at temperatures between 200 and 800 °C and pressure of 100 MPa. The microstructural evolution was studied by means of transmission electron microscopy and Raman spectroscopy. After treatment at 800 °C, the single-wall nanotubes transformed completely to shorter multiwall carbon nanotubes and graphitic particles. The mechanism by which the observed evolution occurs is discussed.