Partial oxidation of methane on Rh/ZrO2 and Rh/Ce-ZrO2 on monoliths: Catalyst restructuring at reaction conditions
2015 (English)In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 174-175, 308-322 p.Article in journal (Refereed) Published
0.5% Rh catalysts on ZrO2 or CeO2-ZrO2, coated on monoliths were tested for partial oxidation of methane, (GHSV=100000h-1). We ran temperature cycles up to 850°C, varying the O2/CH4 ratio from 0.5 to 0.7. The catalysts were characterized by XRD, TPR/TPO, BET and chemisorption. ZrO2 required a long conditioning step, to reach stable performance, while the CeO2-ZrO2 catalyst quickly gained steady activity. The conditioning step is explained with a restructuring of the surface, with the metallic particles becoming smaller. Ceria lowers the ignition temperature by 60°C. At low temperature, ceria allows an increase in CH4 conversion and selectivity to syngas. At high temperature, the CeO2-ZrO2 catalyst significantly increases the CH4 conversion, compared to ZrO2, approaching 100%. However, the selectivity to syngas decreases below 80%. The syngas selectivity is higher at lower O2/CH4 ratio, at any temperature, but the absolute amount of syngas can be larger with more O2.
Place, publisher, year, edition, pages
2015. Vol. 174-175, 308-322 p.
Ceria-zirconia, Methane, Reconstruction, Rhodium, TPR-TPO, Catalysts, Image reconstruction, Synthesis gas, Temperature, Zirconia, Zirconium alloys, Catalyst restructuring, Ignition temperatures, Partial oxidation of methane, Reaction conditions, Stable performance, Temperature cycles, Catalyst activity
IdentifiersURN: urn:nbn:se:kth:diva-167686DOI: 10.1016/j.apcatb.2015.03.012ISI: 000354505100031ScopusID: 2-s2.0-84924944067OAI: oai:DiVA.org:kth-167686DiVA: diva2:816120
QC 201506082015-06-022015-05-222015-06-08Bibliographically approved