| Autor: |
Florea, M., Postole, G., Matei-Rutkovska, F., Urda, A., Neau, F., Massin, L., Gelin, P. |
| Zdroj: |
Catalysis Science & Technology; 2018, Vol. 8 Issue: 5 p1333-1348, 16p |
| Abstrakt: |
Ceria materials doped by Gd and/or Pr were prepared by a precipitation route and calcined in air at 500 and 900 °C. The effects of doping and thermal treatment on the materials' surfaces were studied by X-ray photoelectron and Raman spectroscopies. The redox properties were investigated using temperature-programmed reduction experiments in H2and CH4followed by temperature-programmed oxidation in O2. The catalytic properties of these materials in CH4/H2O reaction in the absence/presence of H2S were evaluated at 750 °C in a large excess of CH4with respect to H2O. The materials were classified by order of reactivity as follows: CPO > CGPO > CeO2> CGO, which can be primarily related to the surface area variation. Comparing the activity per m2of various samples indicates that the catalytic activity is correlated with the Ce3+concentration at the surface as measured by XPS. Gd-doped and undoped samples exhibit the highest surface Ce3+concentration as well as the highest activity in SMR per m2, while Pr-doped samples are the least active (activity per m2) with the lowest surface Ce3+concentrations. H2S has a sharp promoting effect on the catalytic behavior of ceria-based materials, improving the production of H2by almost one order of magnitude. |
| Databáze: |
Supplemental Index |
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