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- Title
The Importance of Strongly Bound Pt–CeO<sub> x </sub> Species for the Water-gas Shift Reaction: Catalyst Activity and Stability Evaluation.
- Authors
Pierre, Danny; Deng, Weiling; Flytzani-Stephanopoulos, Maria
- Abstract
We demonstrate ways to prepare active and stable Pt–CeO x catalysts for the water-gas shift reaction (WGSR). Various synthesis protocols are shown to work; the best being the coprecipitation/gelation method, which suppresses the crystal growth of ceria during calcination by the incorporation of some platinum in the bulk oxide. Metallic platinum nanoparticles are not necessary for an active WGSR catalyst. Reaction light-off occurs at ∼120 °C, where Pt2+ species bound to ceria are still present. No activation period, and no hysteresis phenomena were found. During reaction at reducing conditions, some Pt is reduced, but it is reoxidizable. The stability of these low-content (<2 at.%) Pt/CeO x catalysts is high even in realistic reformate gas streams. To avoid cerium(III) hydroxycarbonate formation at room temperature-shutdown with water condensation, a small amount (∼1%) of gaseous oxygen is added to the reaction gas mixture. Cyclic shutdown/startup operation is thus possible without catalyst degradation.
- Subjects
CERIUM oxides; PLATINUM; CARBONATES; WATER-gas; CATALYST poisoning; PHOTOSYNTHETIC oxygen evolution
- Publication
Topics in Catalysis, 2007, Vol 46, Issue 3/4, p363
- ISSN
1022-5528
- Publication type
Academic Journal
- DOI
10.1007/s11244-007-9013-8