Carbon aerogel supported nickel nanoparticles and nanorods using supercritical deposition

• DOI: 10.1016/j.supflu.2012.02.027
• Publication Date: 2012-03-08T11:15:49Z
• Authors: S.E. Bozbag; L.C. Zhang; M. Aindow; C. Erkey
• Keywords: Nanorod; Supercritical Carbon Dioxide

Abstract Carbon aerogel (CA)–nickel nanocomposites were synthesized by impregnating the CAs with nickel(II) acetylacetonate (Ni(acac) 2 ) from supercritical carbon dioxide at 30 MPa and 60 °C followed by thermal or chemical treatment using H 2 at atmospheric pressure. The CA–Ni(acac) 2 –CO 2 adsorption isotherm was measured at the impregnation condition and found to be linear. The decomposition of Ni(acac) 2 on the CA surface was investigated using thermo-gravimetry and mass-spectroscopy. Propane was found in the gaseous decomposition products. CA–Ni composites were characterized using Infrared (IR) Spectroscopy and characteristic Ni(acac) 2 peaks were found to disappear after thermal or chemical treatments. X-ray diffraction (XRD) data confirmed that after H 2 treatments nickel nanocrystals were present in the CA. Transmission electron microscopy (TEM) revealed the presence of nickel nanostructures dispersed homogeneously on the surface of the CA. In the samples treated with H 2 at 170 °C, the average Ni nanoparticle size increased from 4.9 to 12.9 nm when the Ni loading increased from 3 to 6.5 wt.%. The H 2 treatment at 200 °C resulted in Ni nanorods with diameters of 7–11 nm and lengths of 25–50 nm dispersed throughout the CA surface.