One-dimensional (1D) carbon nanomaterials wrapped by silver nanoparticles were fabricated via a facile and environmentally benign route with the assistance of supercritical carbon dioxide. Transmission electron microscopy, scanning electron microscopy, and energy-dispersive X-ray analysis revealed that carbon nanofibers (CNFs) were densely coated by silver nanoparticles under the optimized experimental condition. In the case of carbon nanotube/silver (CNT/Ag) nanohybrids, these silver nanoparticles on the surface of carbon nanotubes were predominantly spherical in shape with excellent dispersion, and their sizes were smaller than that on carbon nanofibers. The UV−vis spectra presented a surface plasmon resonance vibration band at 448 and 414 nm for CNFs and CNTs, respectively. X-ray diffraction analysis showed that the nanoparticles were of a face centered cubic structure. Some crucial factors, which affect the growing and arraying of Ag nanoparticles along the axis of 1D carbon nanomaterials, had been investigated. As examples for promising applications, the antibacterial activities of the as-prepared one-dimensional nanocomposites were also studied.

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Titania nanocrystals were prepared by a particular way: first, supercritical CO 2 (SC CO 2 ) carried precursor tetrabutyl titanate (TBT) into the confined space of polystyrene (PS) microspheres; second, hydrolysis of TBT was controlled by the confined space of PS microspheres, which had a restraining effect on the hydrolysis rate of TBT; finally, TiO 2 nanocrystals were obtained by calcining PS@TiO 2 composite microspheres. The products obtained after hydrolysis and calcination, that is, PS@TiO 2 composite microspheres and the finally obtained TiO 2 nanocrystals, were characterized by transmission electron microscope and scanning electron microscope, respectively. Further high-resolution transmission electron microscopy and X-ray diffraction (XRD) indicated that the obtained TiO 2 nanocrystals had fine crystalline structure. Additionally, the XRD pattern verified the presence of anatase and rutile in TiO 2 . The nucleation mechanism of TiO 2 nanocrystals in the confined space of PS microspheres was also proposed.