Structural Investigation Of Carbon Morphology On Ni/cerium-zirconium Oxide Catalysts Used For The Biogas Dry Reforming Reaction
Ioannis Tsiaoussis, Nikos D. Charisiou, Maria A. Goula, Lazaros Tzounis, George Vourlias, Ioannis V. Yentekakis, Remi Chassagnon, Valerie Potin, Bruno Domenichini
Volume 2, Issue 12, Page 807-812, Year 2017 | DOI: 10.5185/amp.2017/921
Keywords: Biogas, dry reforming of methane, HRTEM, multi wall carbon nanotubes, Ni catalysts, ceria-zirconia supports.
Abstract: In the present work, we investigated the structural morphology of carbon species deposited on nickel catalysts supported on CeO2-ZrO2 (18.8 wt.% ceria), prepared by wet impregnation, during the dry reforming of methane (DRM) reaction by using Thermo-gravimetric Analysis (TGA), Raman Spectroscopy, X-ray diffraction (XRD), High Resolution Transmission Electron Microscopy (HRTEM) and Scanning Transmission Electron Microscopy- Energy dispersive spectroscopy (STEM-EDS). TGA results show that the amount of deposited carbon decreases upon increasing reaction temperature, which is consistent with the thermodynamics of the reactions responsible for carbon formation, and Raman analysis points to a simultaneous increase in its graphitization degree. XRD measurements reveal the existence of 2H-Graphite and TEM imaging mode as well as SAED patterns depict that in all temperatures under which the catalysts were tested (550, 650, 750 and 800 oC), the formation of multi wall carbon nanotubes (MWCNT). HRTEM observations also reveal that the Ni nanoparticles are often enclosed by the MWCNT. HRTEM images identify nanocrystalline areas with a tetragonal phase, P42/nmc(137), of Ce1-xZrxO2, and STEM-EDS analysis at the nanometer scale confirms a correlation between Ce and Zr in the average atomic ratio (% ), 1 to 5.19 - 6.94 respectively. The results presented herein confirm that biogas mixtures can be used as precursors for the production of MWCNTs. Copyright © 2017 VBRI Press.