Zeolite Cu–ZSM-5: material characteristics and NO decomposition

Ganemi, Bager; Björnbom, Emilia; Demirel, Belma; Paul, Jan

doi:10.1016/s1387-1811(00)00148-7

Cited by 29 publications

(15 citation statements)

References 64 publications

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“…Supplementary Figure 7 shows the powder diffraction results before and after the Cu ion exchange, at RT (a) and 250°C (b) shown in Supplementary Table 4. The results show good agreement with the previous studies 10, 40,41 .…”

Section: Methodssupporting

confidence: 93%

Time-resolved in situ visualization of the structural response of zeolites during catalysis

et al. 2020

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Zeolites are three-dimensional aluminosilicates having unique properties from the size and connectivity of their sub-nanometer pores, the Si/Al ratio of the anionic framework, and the charge-balancing cations. The inhomogeneous distribution of the cations affects their catalytic performances because it influences the intra-crystalline diffusion rates of the reactants and products. However, the structural deformation regarding inhomogeneous active regions during the catalysis is not yet observed by conventional analytical tools. Here we employ in situ X-ray free electron laser-based time-resolved coherent X-ray diffraction imaging to investigate the internal deformations originating from the inhomogeneous Cu ion distributions in Cu-exchanged ZSM-5 zeolite crystals during the deoxygenation of nitrogen oxides with propene. We show that the interactions between the reactants and the active sites lead to an unusual strain distribution, confirmed by density functional theory simulations. These observations provide insights into the role of structural inhomogeneity in zeolites during catalysis and will assist the future design of zeolites for their applications.

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Section: Methodssupporting

confidence: 93%

Time-resolved in situ visualization of the structural response of zeolites during catalysis

et al. 2020

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“…Figure 4b corresponds to fresh Cu-Ce-ZSM-5 and Cu-Ce-ZSM-X. There were diffraction peaks of the ZSM-5 structure (PDF#44-0003) in all samples [25]. With the increase of hydrothermal aging temperature, the intensity of the diffraction peak corresponding to the ZSM-5 structure in Cu-ZSM-X and Cu-Ce-ZSM-X showed a downward trend.…”

Section: Structural Characteristicsmentioning

confidence: 99%

Effect of Hydrothermal Aging Treatment on Decomposition of NO by Cu-ZSM-5 and Modified Mechanism of Doping Ce against This Influence

et al. 2020

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Cu-ZSM-5 and Ce-doped Cu-Ce-ZSM-5 samples were prepared by liquid-phase ion exchange method. The two catalysts were subjected to hydrothermal aging treatment in the simulated flue gas of a coal-fired power station at an ageing temperature of 650–850 °C. The denitration experiment found that the activity of the aged Cu-ZSM-5 was 19.6% to 41% lower than that of the fresh Cu-ZSM-5 at the optimal decomposition temperature of NO at 550 °C, while the aged Cu-Ce-ZSM-5 had only a 14.8% to 31.5% reduction in activity than the fresh Cu-Ce-ZSM-5. The samples were characterized by XRD, BET, H2-TPR, XPS, NO-TPD, etc. The results showed that hydrothermal aging treatment leads to the dealumination of the ZSM-5 framework and reduces the specific surface area and pore volume of the micropore in the sample. It also exacerbates the isolated Cu2+, and the active center {Cu2+-O2−-Cu2+}2+ dimers migrate towards the sample surface and form inactive CuO. Doping with Ce can promote the dispersion of Cu(OH)+, which was the precursor of {Cu2+-O2−-Cu2+}2+. Ce3+ can preferentially occupy the less active bridged hydroxyl exchange sites, so that copper ions occupy the more active aluminum hydroxyl sites, thereby inhibiting the migration of active centers.

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“…[7][8][9][10][11][12][13][14] 其中 Fe-ZSM-5 催化剂因其高活性、高选择性和高抗硫性被广泛研究. [10][11][12] [15][16][17][18][19] 但用于 NH3-SCR 反应的研究报道较少, 且效果不太理想. 9,20…”

Section: 引言unclassified

Catalytic Performance and Steady-State Kinetics of Cu-ZSM-5 for Selective Catalytic Reduction of NO with NH<sub>3</sub>

张秋林¹,

徐海迪²,

邱春天³

et al. 2012

Acta Physico-Chimica Sinica

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A series of Cu-ZSM-5 catalysts with different Cu loadings were prepared by an incipient wetness impregnation method. These catalysts were used for studies of selective catalytic reduction (SCR) of NO by NH3. The results showed that Cu-ZSM-5 with 5% Cu loading showed the best catalytic activity, the conversion of NO was more than 80% over the temperature range 198-470°C, and the highest NO conversion was 96.5%. The SCR activity was only influenced slightly by the addition of H2O or SO2. Visible diffraction of the CuO phase was observed when the Cu content was above 5%. The results of steady-state kinetics studies indicated that the SCR reaction over Cu-ZSM-5 with 5% Cu loading was zero-order with respect to NH3, first-order with respect to NO, and nearly half-order with respect to O2. The apparent activation energy for the reaction was found to be 47.7 kJ•mol-1 .

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Zeolite Cu–ZSM-5: material characteristics and NO decomposition

Cited by 29 publications

References 64 publications

Time-resolved in situ visualization of the structural response of zeolites during catalysis

Time-resolved in situ visualization of the structural response of zeolites during catalysis

Effect of Hydrothermal Aging Treatment on Decomposition of NO by Cu-ZSM-5 and Modified Mechanism of Doping Ce against This Influence

Catalytic Performance and Steady-State Kinetics of Cu-ZSM-5 for Selective Catalytic Reduction of NO with NH<sub>3</sub>

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