Reversible interconversion behavior of Ag species in AgHZSM-5: XRD, 1H MAS NMR, TPR, TPHE, and catalytic studies

Ausavasukhi, Artit; Suwannaran, Suratsawadee; Limtrakul, Jumrus; Sooknoi, Tawan

doi:10.1016/j.apcata.2008.04.026

Cited by 31 publications

(21 citation statements)

References 38 publications

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“…[1][2][3][4][5][6][7][8] Particularly, silver-based catalysts have become the object of several studies for the abatement of nitrogen oxides (NOx) and unburnt hydrocarbon (HCs) emissions from exhaust gas streams. Ag/Al 2 O 3 is known to be one of the most effective catalysts for the selective catalytic reduction of NOx (SCR-NOx) with hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

Study of the Nature and Location of Silver in Ag-Exchanged Mordenite Catalysts. Characterization by Spectroscopic Techniques

et al. 2013

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Catalysts based on Na-mordenite (symbolized as 'M') exchanged with 5, 10 and 15 wt. % of Ag were characterized by XPS, EXAFS, XANES and UV-Vis DRS spectroscopic techniques in order to investigate the effect of different treatments on the chemical state and surface concentration of silver species. The Ag x M catalysts were analyzed in oxidizing (O 2 ) or reducing (H 2 /Ar) atmospheres and also after being used in the selective catalytic reduction of NOx or in successive cycles of toluene adsorption/desorption.In calcined samples, EXAFS profiles showed two types of Ag-O spheres of coordination, one due to a dispersed phase of silver oxide and the other, to Ag + ions in interaction with the oxygen of the zeolite framework. The UV-Vis DRS spectra showed the coexistence of isolated Ag + , Ag n δ+ (n < 10) cationic clusters and Ag x O particles. In addition, through the modified Auger parameter (α'), calculated from XPS measurements, it was possible to identify Ag + ions at exchange sites (α'~722 eV) and Ag x O (α'~725 eV) highly dispersed on the surface. Both species constitute stable active centers for the SCR of NOx under severe reaction conditions. However, during the adsorption-desorption of toluene, the reduction of silver oxides produces Ag(0) due to thermal hydrocarbon decomposition.

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Section: Introductionmentioning

confidence: 99%

Study of the Nature and Location of Silver in Ag-Exchanged Mordenite Catalysts. Characterization by Spectroscopic Techniques

et al. 2013

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“…The first peak is associated with the reduction of Ag ? to Ag cluster and the second one is attributed to the reduction of Ag cluster to nano Ag particles [19,20]. For the Co-ZSM-5 sample, the peak at 375°C is attributed to the reduction of Co 3 O 4 species (Co 3?…”

Section: Catalyst Characterizationmentioning

confidence: 98%

Enhanced Low-Temperature Activity of Ag-Promoted Co-ZSM-5 for the CH4-SCR of NO

Chen

Zhu

et al. 2010

Catal Lett

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Ag-promoted Co-ZSM-5 catalyst was prepared and tested for the selective catalytic reduction of NO with methane. The low-temperature activity and water-resistant ability of the promoted catalyst were markedly improved in comparison to Co-ZSM-5. The NO conversion was about 100% in the temperature range of 350-550°C at a space velocity of 6,000 h -1 and nearly 60% in the presence of 2% water steam. The results showed that with Ag presence, the redox nature of cobalt species changed. The improvement of low-temperature activity and water-resistance of catalyst is attributed to the suppression of methane combustion and the formation of surface nitrate species.

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“…3a. The therein depicted NH 3 -TPD profiles exhibit the two characteristic peaks for H-ZSM-5, resulting from NH 3 adsorption on (i) SiÀOH and (ii) SiÀOHÀAl groups [22][23][24]. In the TPAD profiles of the catalyst samples with a Si/Al ratio of 20 (Fig.…”

Section: Characterisationmentioning

confidence: 99%

Simultaneous selective catalytic reduction (SCR) of NOx and N2O over Ag/ZSM-5 – Catalytic studies and mechanistic implications

Schuricht

Reschetilowski

2012

Microporous and Mesoporous Materials

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Reversible interconversion behavior of Ag species in AgHZSM-5: XRD, 1H MAS NMR, TPR, TPHE, and catalytic studies

Cited by 31 publications

References 38 publications

Study of the Nature and Location of Silver in Ag-Exchanged Mordenite Catalysts. Characterization by Spectroscopic Techniques

Study of the Nature and Location of Silver in Ag-Exchanged Mordenite Catalysts. Characterization by Spectroscopic Techniques

Enhanced Low-Temperature Activity of Ag-Promoted Co-ZSM-5 for the CH4-SCR of NO

Simultaneous selective catalytic reduction (SCR) of NOx and N2O over Ag/ZSM-5 – Catalytic studies and mechanistic implications

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