Selectivity loss of Pt/CeO{sub 2} PROX catalysts at low CO concentrations: mechanism and active site study.
- Chemical Sciences and Engineering Division
CO and H{sub 2} oxidation were studied over a series of Pt/CeO{sub 2} catalysts with differing Pt loadings and dispersions. Kinetic rate analysis confirms the presence of dual Langmuir-Hinshelwood (L-H) and Mars and van Krevelen (M-vK) pathways and is used to explain the loss in CO oxidation selectivity at low CO concentrations. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) shows the strong CO coverage dependence on both CO and O{sub 2} concentrations and explains the transition from L-H to M-vK reaction character. Redox site measurements are performed on Pt/CeO{sub 2} catalysts by anaerobic titrations under conditions where the M-vK pathway dominates the reaction rate. Similar redox site densities per interfacial Pt atom suggest that interfacial Pt-O-Ce sites are responsible for M-vK redox activity.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Purdue Univ.; Purdue Research Foundation
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 1009803
- Report Number(s):
- ANL/CSE/JA-69600; TRN: US201106%%842
- Journal Information:
- J. Catal., Vol. 273, Issue 1 ; Jul. 2010
- Country of Publication:
- United States
- Language:
- ENGLISH
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