| Popis: |
Hydrogen is a clean energy carrier and highest energy density fuel. Water gas shift (WGS) reac- tion is an important reaction to generate hydrogen from steam reforming of CO. A new WGS catalyst, Ce1−xRuxO2−δ (0 ≤ x ≤ 0.1) was prepared by hydrothermal method using melamine as a complexing agent. The Catalyst does not require any pre-treatment. Among the several compositions prepared and tested, Ce0.95Ru0.05O2−δ (5% Ru 4+ ion substituted in CeO2) showed very high WGS activity in terms of high conver- sion rate (20.5 μmol.g −1 .s −1 at 275 ◦ C) and low activation energy (12.1 kcal/mol). Over 99% conversion of CO to CO2 by H2O is observed with 100% H2 selectivity at ≥ 275 ◦ C. In presence of externally fed CO2 and H2 also, complete conversion of CO to CO2 was observed with 100% H2 selectivity in the temperature range of 305-385 ◦ C. Catalyst does not deactivate in long duration on/off WGS reaction cycle due to absence of surface carbon and carbonate formation and sintering of Ru. Due to highly acidic nature of Ru 4+ ion, surface carbon- ate formation is also inhibited. Sintering of noble metal (Ru) is avoided in this catalyst because Ru remains in Ru 4+ ionic state in the Ce1−xRuxO2−δ catalyst. Keywords. WGS reaction; Ru 4+ ion in CeO 2; Pt catalyst; H2 selectivity. |
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