ΔΗΜΟΣΙΕΥΣΗ - INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
Title: Ni/Y2O3–ZrO2 catalyst for hydrogen production through the glycerol steam reforming reaction [view paper]
Journal: International Journal of Hydrogen Energy - In press.
Authors: N.D. Charisiou1,*, G. Siakavelas1, L. Tzounis2, B. Dou3, V. Sebastian 4,5, S.J. Hinder6, M.A. Baker6, K. Polychronopoulou7,8, M.A. Goula1,*
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
3School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China
4Chemical and Environmental Engineering Department, Instituto de Nanociencia de Aragón (INA) and Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50018 Zaragoza, Spain
5Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, CIBERBBN, 28029 Madrid, Spain
6The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 4DL, UK
7Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, UAE
8Center for Catalysis and Separation, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, UAE
Abstract
In the study presented herein, the catalytic activity and stability of a Ni catalyst supported on Y2O3-ZrO2 was examined for the first time in the glycerol steam reforming reaction and compared with a Ni/ZrO2. The addition of Y2O3 stabilized the ZrO2 tetragonal phase, increased the O2 storage capacity of the support and the medium strength acid sites of the catalyst, and although the Ni/Zr catalyst had a higher concentration of basic sites, the Ni/YZr presented more stable monodentate carbonates. Moreover, the Ni/YZr had substantially higher Ni surface concentration and smaller Ni particles. These properties influence the gaseous products’ distribution by increasing the H2 yield and selectivity and preventing the transformation of CO2 to CO by inhibiting the reverse water gas shift (RWGS) reaction from taking place. For both catalysts the main liquid products identified were allyl alcohol, acetaldehyde, acetone, acrolein, acetic acid and acetol; these were subsequently quantified. The time-on-stream experiments showed that the Ni/YZr was more stable during reaction and had a higher H2 yield after 20 h (2.17 in comparison to 1.50 mol H2/mol C3H8O3, for the Ni/Zr). Extensive investigation of the carbon deposits showed that although lower amounts of coke were deposited on the Ni/Zr catalyst, these structures were more graphitic in nature and had fewer defects, which means they were harder to oxidize. Moreover, transmission electron microscopy (TEM) analysis showed that sintering of Ni nanoparticles during the reaction was significant for the Ni/Zr catalyst, as the mean particle diameter increased from an initial value of 48.2 to 67.9 nm, while it was almost absent on the Ni/YZr catalyst (the mean particle diameter increased from 42.1 to 47.4 nm).