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This work concentrates on the study of catalyst and buffer layer effects on growth of carbon nanowalls (CNWs) on glass substrates that coated with various metal nanocatalysts and/or buffer layers using hot filament chemical vapor deposition (HF-CVD) technique. A combination of C2H2/NH3/H2 renders the growth of carbon nanostructures (carbon nanowalls). Parameters affecting the growth of the CNWs such as C2H2 flow ratio, deposition time, and substrate temperature are investigated. Low temperature plasma is applied for deposition of the Fe and Al thin films as nanocatalyst and/or buffer layer on the glass substrate. Surface morphology of the substrate is observed using the atomic force microscopy (AFM) technique, while the thicknesses were measured by means of Rutherford back scattering (RBS) technique. The samples utilized are characterized by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy techniques. One of the important conclusions in this work is that the increasing of the substrate temperature from 600° C to 700° C caused to the increasing of the crystallite size of the CNWs that were grown on the Fe and Al nanocatalysts. It is also determined that, deposition of the Al nanolayer under the Fe naocatalyst as a buffer layer caused to the increasing of the crystallite size of the CNWs that were grown on the Fe nanocatalyst. [ABSTRACT FROM AUTHOR]

The Ni/Al2O3 nanocatalysts were prepared by Sol-Gel method and promoted with Cobalt and Copper. Samples were characterized by XRD, SEM, TEM, BET, FTIR, and TG-DTG analysis. This work is primarily focused on the development of novel nickel-based nanocatalysts to achieve stable operation for CO2 reforming of CH4. Three Ni-based nanocatalysts with the same Ni content (10 wt %) were synthesized. Addition of 3 wt.% Cu to the Ni/Al2O3 nanocatalyst enhanced the stability and better distribution of the active phase, however in the case of Co addition in Ni-Co/Al2O3 nanocatalyst, it is enhanced specific surface area of the sample. Achieved picks by XRD were noted that are very weak and broad as the size of active phase particles are very small. [ABSTRACT FROM AUTHOR]