Estimation of the fractions of different nuclear iron species in uniformly metal-exchanged Fe-ZSM-5 samples based on a Poisson distribution

Hydrothermal Deactivation of Fe-ZSM-5 Prepared by Different Methods for the Selective Catalytic Reduction of NOx with NH3

“…The percentage of each band with respect to the total area of the spectrum was shown in Table 2, in which I 1 , I 2 , and I 3 represented the percentage of the area of the subbands at Ȝ 295 nm, 300 nm < Ȝ 400 nm, and Ȝ > 400 nm, respectively [17,21]. [19] reported that for Fe-ZSM-5 prepared by the IE method with exchange degree (Fe/Al) below 0.45, the activity of the catalyst at low temperature (below 300 o C) was determined by the concentration of monomeric iron sites.…”

“…According to the results of UV-Vis diffuse reflectance spectroscopy (DRS), Mössbauer, and electron paramagnetic resonance (EPR) spectroscopy, the Fe species coexisting on Fe-ZSM-5 in some studies of the application of Fe-ZSM-5 in NH 3 [14,[18][19][20][21][22]. Thus, different Fe species showed different catalytic performance in the NH 3 -SCR reaction.…”

“…BaSO 4 was used as the reference material. The Fe-ZSM-5 catalysts were diluted with BaSO 4 at a ratio of 1:4 [18,21]. The spectra were converted with the Kubelka-Munk (K-M) function F(R) for comparison.…”

The effect of Fe species distribution and acidity of Fe-ZSM-5 on the hydrothermal stability and SO2 and hydrocarbons durability in NH3-SCR reaction

“…2. Generally, the bands below 300 nm are assignable to isolated Fe 3+ species located on ion exchange sites, while bands above 300 nm are assignable to oligomeric clusters (between 300-400 nm) and Fe2O3 particles (above 400 nm) [17,18]. As shown in Fig.…”

“…The bands related to NH3 adsorbed species appearing at 3500-250 cm −1 can be assigned to the N-H stretching vibration of adsorbed NH3 [14]. The band at 1480 cm −1 is assigned to the symmetric bending vibration of NH4 + chemisorbed onto Brønsted acid sites [14,[17][18][19][20]. The negative band at 3610 cm −1 can be assigned to the OH stretch of Brønsted acid sites resulting from the interaction of surface hydroxyls with NH3, which may reflect the relative concentration of Brønsted acid sites on the Fe-ZSM-5 [10,[19][20][21].…”