ΔΗΜΟΣΙΕΥΣΗ - INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

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Title: Ni supported on CaO-MgO-Al₂O₃ as a highly selective and stable catalyst for H₂ production via the glycerol steam reforming reaction [view paper]

 

Journal: International Journal of Hydrogen Energy 44 (2019) 256-273.

 

Authors: N.D. Charisiou¹, K.N. Papageridis¹, L. Tzounis², V. Sebastian^3,4, S.J. Hinder⁵, M.A. Baker⁵, M. AlKetbi⁶, K. Polychronopoulou⁶, M.A. Goula^1,*

 

Affiliations:

¹Laboratory of Alternative Fuels and Environmental Catalysis (LAFEC), Department of Environmental and Pollution Control Engineering, Western Macedonia University of Applied Sciences, GR-50100, Greece

²Composite and Smart Materials Laboratory (CSML), Department of Materials Science & Engineering, University of Ioannina, GR-45110, Ioannina, Greece

³Chemical and Environmental Engineering Department & Nanoscience Institute of Aragon (INA), University of Zaragoza, Zaragoza, SP-50018, Spain

⁴Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, CIBERBBN, 28029 Madrid, Spain

⁵The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 4DL, UK

⁶Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, UAE

 

ABSTRACT

A comparative study of the GSR performance for Ni/CaO-MgO-Al₂O₃ and Ni/Al₂O₃ catalysts is reported. Catalysts were synthesized applying the wet impregnation method at a constant metal loading (8 wt. %). Synthesized samples were characterized by N₂ adsorption/ desorption, ICP, BET, XRD, NH₃-TPD, CO₂-TPD, H₂-TPR, XPS and TEM, STEM-HAADF and EDS. The carbon deposited on their surface under reaction conditions was characterized by TPO, Raman and TEM. It was proven that the use of CaO-MgO as alumina modifiers leads to smaller nickel species crystallite size, increased basicity and surface amount of Ni⁰ phase. Thus, it increases the conversion to gaseous products favoring H₂ and CO₂ production to the detriment of CO formation, by enhancing the water gas-shift (WGS) reaction. No liquid products were produced by the Ni/modAl catalyst over 550^oC, whereas time on stream results confirmed that deactivation can be prevented, as apart from decreasing the amount of coke deposition the nature of carbon was altered towards less graphitic and more defective structures.