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Fe-zeolite: Influence of precursors and preparation method

Fe-zeolite: Influence of precursors and preparation method. Dong Xuesong. Fe-zeolite: Influence of precursors and preparation method. Anunziata et al. [1] : i -C 4 H 10 -SCR on Fe/ZSM-11 catalyst.

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Fe-zeolite: Influence of precursors and preparation method

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  1. Fe-zeolite: Influence of precursors and preparation method Dong Xuesong

  2. Fe-zeolite: Influence of precursors and preparation method • Anunziata et al. [1]: i-C4H10-SCR on Fe/ZSM-11 catalyst. • NH4-ZSM-11; Wetness impregnation; Precursors FeSO4 (Samples: A, B. Fe content: 1 and 3 wt%) and Fe(NO3)3 (Sample:C 3 wt%). Table 1 Summary of catalyst characteristics [1] O.A. Anunziata. Applied Catalysis A:General 264 (2004) 93–101.

  3. Fe-zeolite: Influence of precursors and preparation method Fig.1 Catalytic activity of Fe-zeolites for NOx SCR using samples A, B and C

  4. Fe-zeolite: Influence of precursors and preparation method • XRD result indicated only in the sample C: hematite phase (ɑ-Fe2O3) Fig.2 Experimental results from FTIR spectra of pyridine-Lewis sites (Fen+-Z) for samples A, B and C desorbed at 400 ◦C and 10−4 Torr.

  5. Fe-zeolite: Influence of precursors and preparation method • They concluded: The NOx conversion appears as a function of the presence of Fe2+ while Fe3+ is less active for the SCR of NOx with i-C4H10. • However, the oxidation state difference rather than the anion may lead to the difference. • Few paper investigates the precursors effect on Fe-zeolites SCR.

  6. Fe-zeolite: Influence of precursors and preparation method • Mhamdi et al. [2]: ethylene ammoxidation • H-ZSM-5; Solid-State ion exchange; Co precursors (acetate, chloride, nitrate or formate); nominal Co/Al=1 • Activity: Ac is best in activity and selectivity. • Chloride, nitrate or formate: Co oxide and isolated Co2+ cationic ion exchange position.while Ac leads to most isolated Co2+ • However, Kawi et al. [3] observed no difference between Co(NO3)2 and Co(acac)2 for HC-SCR. [2] M. Mhamdi . Applied Catalysis A: General 357 (2009) 42–50 [3] S. Kawi. Applied Catalysis B: Environmental 50 (2004) 37–47

  7. Fe-zeolite: Influence of precursors and preparation method • The role of chlorine • Ávila et al. [4]: NOx reduction by CH4 on Pd/Al2O3 • Chloride, nitrate or acetate; Impregnation • PdCl2: much better acitivity especially at high temperature. • Cl- migrate to the active Pd2+ centres. • Sobczak et al. [5] found chlorine electron transfer to oxygen and promotes NO oxidation on Au/MCM-41 for HC-SCR. [4] P. Ávila.Chemical Engineering Journal 150 (2009) 8–14 [5] Sobczak. Journal of Catalysis 245 (2007) 259–266

  8. Fe-zeolite: Influence of precursors and preparation method • 陈银飞等[6]，Fe/β催化NH3-SCR反应 • β分子筛，真空浸渍法，铁前驱体：Fe(NO3)3, FeCl3, Fe(C2H5)2, Fe的理论负载量为1.0%。 Fig.3 Catalytic activity of different Fe/β catalyst samples for NH3-SCR [6].陈银飞等，Chinese Journal of Catalysis 33 (2012) 576-580

  9. Fe-zeolite: Influence of precursors and preparation method • A. Shishkin et al.[7] :NH3-SCR on Fe-ZSM-5 catalysts • H-ZSM-5; incipient wetness impregnation; procedure Fe(NO3)3·9H2O, solvent-methanol(Fe-Z1) or 50wt% methanol in water(Fe-Z2) • H-ZSM-5; aqueous ion exchange; FeCl2 (Fe-Z3) • The preparation route of Fe-ZSM-5 is importance for the activity and selectivity for NH3-SCR, the most active catalyst is the Fe-Z3 sample. [7] A. Shishkin. Topics in Catalysis 56 (2013) 567-575

  10. Fe-zeolite: Influence of precursors and preparation method • The activity and XPS studies show further that a higher fraction of divalent iron species facilitates the SCR reaction. • On the contrary, a higher fraction of trivalent iron species facilitates the oxidation of NH3. • It is in agreement with Anunziata’s study that Fe2+ is more active than Fe3+ for the SCR.

  11. My opinion and plan • The influence of precursors is affect by preparation method. • Incipient wetness impregnation; Solid-state ion exchange; aqueous ion exchange • Precursors: chloride, nitrate, sulfate, acetate. Fe3+ • Questions ? • Solid-state ion exchange: Replace He by N2?

  12. Thank you!

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