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Hydrogen Production by Aqueous Phase reforming of Glycerol Over Supported Platinum Catalysts

Larimi, Afsaneh Sadat | 2016

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 48891 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Kazemeini, Mohammad; Mohammadi, Ali Asghar
  7. Abstract:
  8. The aqueous phase reforming (APR) of glycerol is an attractive yet challenging pathway to convert abundant biomass into value added hydrogen. Pt catalysts have received attention due to their ability to produce hydrogen-rich gas under APR conditions. In this work, the conversion of glycerol into hydrogen is demonstrated using Pt0.05CexZr0.95-xO2 (x=0, 0.29, 0.475, 0.66 and 0.95) solid solution catalysts and a series of M-doped Pt-MgO (M = Pd, Ir, Re, Ru, Rh and Cr) sheet-shaped nano-catalysts. Both characteristic (XRD, BET, H2-TPR, CO-chemisorption, TEM and XPS) and reactivity measurements were used to investigate the activity of the catalysts. Results indicated that reactivity depended on the Ce/Zr ratio, which in turn affected the Pt oxidation state, active metal dispersion and surface area, and particle size. Among these catalysts Pt0.05Ce0.475Zr0.475O2 showed the highest carbon to gas conversion (95%), highest H2 yield (93%), highest H2 selectivity (98%) and at least 50 h of stability. The overall catalytic performance decreased in the order Pt0.05Ce0.475Zr0.475O2 > Pt0.05Ce0.29Zr0.66O2 > Pt0.05Zr0.95O2 > Pt0. The APR activity of Pt-M-MgO catalysts depended on the type of the M dopant used. The APR activity varied in the following order: Rh > Pd > Cr> Ir > undoped ≈ Ru > Re, with the Rh-promoted catalyst having an activity of about one order of magnitude higher than the Re-promoted catalyst at 250°C. It was found that M-promotion had a significant effect on the reducibility of the Pt-MgO catalysts thus affecting their APR activity
  9. Keywords:
  10. Biomass ; Aqueous Phase Reforming ; Platinum Catalyst ; Hydrogen Producing ; Renewable Hydrogen ; Glycerol

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