Kinetic studies of the stability of Pt for No oxidation: effect of sulfur and long-term aging.
- Chemical Sciences and Engineering Division
The stability of Pt catalysts for NO oxidation was analyzed by observing the effect of pre-adsorbed sulfur on the reaction kinetics using a series of Pt/SBA-15 catalysts with varying Pt particle sizes (ca 2-9 nm). Our results indicate that sulfur addition did not influence catalyst deactivation of any of the Pt catalysts, resulting in unchanged turnover rates (TOR) and reaction kinetics. The presence of sulfur on Pt was confirmed by X-ray absorption fine structure spectroscopy (EXAFS) under reducing environments. However, exposure of the catalyst to NO oxidation conditions displaced sulfur from the first coordination shell of Pt, yielding Pt-O bonds instead. Re-reduction fully recovered the Pt-S backscattering, implying that sulfur remained near the Pt under oxidizing conditions. X-ray photoelectron spectroscopy (XPS) and chemisorption measurements confirmed the presence of sulfur near platinum. The invariance of the NO oxidation reaction to sulfur poisoning is explained by sulfur displacement to interfacial sites and/or sulfur binding on kinetically irrelevant sites. Formation of Pt oxides remains as the main source of catalyst deactivation as observed by kinetic and X-ray absorption spectroscopy (XAS) measurements.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 1029109
- Report Number(s):
- ANL/CSE/JA-71435; JCTLA5; TRN: US201123%%14
- Journal Information:
- Journal of Catalysis, Vol. 282, Issue 1; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
Identification of Surface Structures in Pt 3 Cr Intermetallic Nanocatalysts
Correlation of Water Activation, Surface Properties, and Oxygen Reduction Reactivity of Supported PtM/C Bimetallic Electrocatalysts Using XAS