Low-temperature catalytic decomposition of ethylene into H2 and secondary carbon nanotubes over Ni/CNTs
AuthorSavva, Petros G.
Ryzkov, V. A.
Efstathiou, Angelos M.
SourceApplied Catalysis B: Environmental
Google Scholar check
MetadataShow full item record
The present work reports on the production of H2 and secondary carbon nanotubes (CNTs) during catalytic decomposition of ethylene over a novel catalytic system, namely, nickel supported on carbon nanotubes (Ni/CNTs) at remarkably low-temperatures, e.g. 400 °C. A number of catalyst parameters were investigated, namely the chemical nature of support, the Ni metal loading (0.1-10 wt%), the nature of nickel metal precursor (organometallic vs. inorganic) used during catalyst synthesis, and the nature of transition metal used (e.g. Co, Fe, Cu, Ni). Among the different Ni/CNT supported catalysts investigated, 0.5 wt% Ni/Ros1-B1 (Ros1-B1 a commercial CNT) presented the highest activity in terms of H2 production (296 mol H2/gNi) and carbon capacity (3552 gC/gNi). In terms of transition metal used as active catalytic phase, the activity (moles H2 per gram of metal) was found to decrease in the order Co ≫ Fe > Cu. The activity of supported Ni and Co catalysts was found to strongly depend on the metal loading. The structural and morphological features of primary (catalytic support) and secondary carbon nanotubes produced during ethylene decomposition at 400 °C were studied using X-ray Diffraction (XRD), scanning electron microscopy (SEM), High-resolution Transmission Electron Microscopy (HRTEM), and X-ray Photoelectron Spectroscopy (XPS). The production of secondary carbon nanotubes at 400 °C was confirmed after using HRTEM and after a comparison with the primary carbon nanotubes of catalyst support was made. Different regeneration conditions (use of oxygen or steam) were investigated in order to remove by gasification the amorphous carbon deposited under reaction conditions. Oxygen appeared to be a better regeneration reagent than steam, where after ten consecutive reaction/regeneration cycles the 0.5 wt% Ni/Ros1-B1 catalyst showed high and stable activity with time on stream. © 2009 Elsevier B.V. All rights reserved.
Showing items related by title, author, creator and subject.
Low-temperature purification of gas streams from phenol by steam reforming over novel supported-Rh catalysts Constantinou, D. A.; Efstathiou, Angelos M. (2010)The purification of gas streams from phenol at low-temperatures (350-550 °C) was investigated by its reaction with steam over novel catalytic systems, namely 0.5 wt% Rh supported on Ce0.15Zr0.85O2, Ce0.15Zr0.83Mg0.02O2 and ...
Tailoring MgO-based supported Rh catalysts for purification of gas streams from phenol Polychronopoulou, Kyriaki; Giannakopoulos, K.; Efstathiou, Angelos M. (2012)The present work is focused on the sol-gel synthesis, characterization and catalytic performance evaluation of novel Mg-Ce-Zr-O-based mixed oxides supported Rh catalysts for the purification of H 2-rich gas streams from ...
Low-temperature conversion of phenol into CO, CO 2 and H 2 by steam reforming over La-containing supported Rh catalysts Constantinou, D. A.; álvarez-Galván, M. C.; Fierro, José Luis García; Efstathiou, Angelos M. (2012)The steam reforming of phenol in the low-temperature range of 350-550°C was studied over 0.5wt% Rh supported on Ce 0.15Zr 0.85O 2, Zr 0.93La 0.07O 2, and Ce 0.13Zr 0.83La 0.04O 2 mixed metal oxides. The reforming specific ...