To examine the colloid stability of hybrid materials, as-synthesized CNTs/Fe3O4 inorganic hybrid (FeCl3 6H2O:CNTs weight ratio of 8:1, S3) can be easily dispersed in ethanol and remains very stable for at least 2 weeks at room temperature. These ‘‘magnetic CNTs’’ could be quickly separated from their dispersion by holding the sample close to a commercial magnet as shown in Fig. 6, indicating that it is possible to manipulate these magnetic CNTs by an external magnetic field.