In situ FTIR spectroscopy of highly dispersed FeOx catalysts for NO reduction: Role of Na promoter
| Autor: | Louisa Savereide, David J. Childers, Charles A. Roberts, Torin C. Peck, Justin M. Notestein |
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| Rok vydání: | 2016 |
| Předmět: |
Chemistry
Inorganic chemistry Oxide Iron oxide 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Catalysis 0104 chemical sciences chemistry.chemical_compound Adsorption Fourier transform infrared spectroscopy 0210 nano-technology Spectroscopy Stoichiometry Carbon monoxide |
| Zdroj: | Catalysis Today. 267:56-64 |
| ISSN: | 0920-5861 |
| DOI: | 10.1016/j.cattod.2015.12.014 |
| Popis: | The effect of Na on highly dispersed FeOx impregnated onto CeO2 via the unique precursor Na/Fe-ethylenediaminetetraacetate (NaFeEDTA) was investigated by comparison to a series of well-defined catalysts synthesized by the traditional precursor Fe(NO3)3 both with and without Na addition. Catalysts were evaluated for steady-state NO reduction by CO and activities varied based on synthesis method and Fe:Na ratio. Na contributed a promoter effect when added at a stoichiometric ratio (Fe:Na = 1), providing an explanation for the higher activity of NaFeEDTA/CeO2 for NO reduction by CO. Activity decreased when excess Na was present in Fe(NO3)3 catalysts, but the stoichiometric promoter effect persisted up to ∼4.0 Fe/nm2. In situ Fourier transform infrared (FTIR) spectroscopy during NO adsorption revealed the presence of unique NO adsorption species (1460 cm−1) on the NaFeEDTA/CeO2, suggesting enhanced NO adsorption due to Na. At reaction temperature, FTIR bands of bulk nitrates on CeO2 were quantitatively shown to more rapidly undergo NO reduction catalytic transformations over NaFeEDTA/CeO2. These results increase understanding of mechanistic effects of Na on NO reduction over FeOx/CeO2 catalysts and serve to guide future design of oxide-based emission control catalysts that are free of Pt-group metals. |
| Databáze: | OpenAIRE |
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