A comparison of the activity and deactivation of Ag/Al2O3 and Cu/ZSM-5 for HC-SCR under simulated diesel exhaust emission conditions

Houel, Valérie; James, David W.; Millington, Paul; Pollington, Stephen; Poulston, Stephen; Rajaram, Raj R.; Torbati, Reza

doi:10.1016/j.jcat.2004.12.003

Cited by 64 publications

(27 citation statements)

References 21 publications

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“…A clear deactivation of NO conversion was observed over SA and Mg (10) SA catalysts observed at low temperature range 300-400°C and activation at higher temperatures ([400°C). These results are very much in agreement with the reported literature [31][32][33][34]. Meunier and Ross [31] and Angelidis and Kruse [35] noted that the activation of the catalyst occurred at high temperatures in the presence of SO 2 .…”

Section: In the Presence Of Osupporting

confidence: 92%

Influence of Mg Addition on the Catalytic Activity of Alumina Supported Ag for C3H6-SCR of NO

et al. 2009

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The influence of different magnesium (Mg) weight percentages (1, 2.5, 5, 7.5 and 10) over silver (3 wt%) impregnated alumina (SA) catalyst was investigated for the reduction of NO by C 3 H 6 . Mg doped SA catalysts were prepared by conventional impregnation method and characterized by XRD, BET-SA, ICP-MS, XPS, SEM, UV-DRS, H 2 -TPR and O 2 -TPD. The existence of MgO and MgAl 2 O 4 phases on Mg doped SA catalysts were observed from XRD and XPS analyses. Existence of high percentage MgAl 2 O 4 phase on 5% Mg doped SA catalyst (Mg (5) SA) enhances the dispersion and stabilization of silver phases (Ag 2 O). Mg (5) SA catalyst shows a 51% of high selectivity (NO to N 2 ) in presence of SO 2 (80 ppm) at low temperatures (350°C) and maintained high selectivity's with a wide temperature window (350-500°C). An optimal high surface availability of Ag 0 and Ag ? species were observed from XPS analysis over Mg (5) SA catalyst. H 2 -TPR analysis shows high temperature reduction peak over Mg (5) SA compared to SA catalyst. XPS analysis confirms the high percent availability of MgAl 2 O 4 species over Mg (5) SA catalyst. DRIFTS study reveals the molecular evidences for the evolution of enolic species during NO reduction over the highly active Mg (5) SA catalyst at low temperatures. It also confirms further transformation of enolic species into -NCO species with NO ? O 2 and finally into N 2 and CO 2 .

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Section: In the Presence Of Osupporting

confidence: 92%

Influence of Mg Addition on the Catalytic Activity of Alumina Supported Ag for C3H6-SCR of NO

et al. 2009

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“…From a practical point of view, a catalyst used for the SCR of NO x should be resistant to both SO 2 and H 2 O in real exhaust gases; and the type of reductant is an important factor for the SO 2 [12][13][14][15][16]. However, ethanol was extremely effective for the SCR of NO x over Ag/Al 2 O 3 even in the presence of H 2 O and SO 2 , which was confirmed by diesel engine bench tests [7,[17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Review of Ag/Al2O3-Reductant System in the Selective Catalytic Reduction of NO x

Zhang

et al. 2008

Catal Surv Asia

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Ag/Al 2 O 3 is a promising catalyst for the selective catalytic reduction (SCR) by hydrocarbons (HC) of NO x in both laboratory and diesel engine bench tests. New developments of the HC-SCR of NO x over a Ag/ Al 2 O 3 catalyst are reviewed, including the efficiencies and sulfur tolerances of different Ag/Al 2 O 3 -reductant systems for the SCR of NO x ; the low-temperature activity improvement of H 2 -assisted HC-SCR of NO x over Ag/ Al 2 O 3 ; and the application of a Ag/Al 2 O 3 -ethanol SCR system with a heavy-duty diesel engine. The discussions are focused on the reaction mechanisms of different Ag/ Al 2 O 3 -reductant systems and H 2 -assisted HC-SCR of NO x over Ag/Al 2 O 3 . A SO 2 -resistant surface structure in situ synthesized on Ag/Al 2 O 3 by using ethanol as a reductant is proposed based on the study of the sulfate formation. These results provide new insight into the design of a high-efficiency NO x reduction system. The diesel engine bench test results showed that a Ag/Al 2 O 3 -ethanol system is promising for catalytic cleaning of NO x in diesel exhaust.

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“…One of the promising approaches to eliminate NO x is to use the selective catalytic reduction (SCR) with hydrocarbons (HC-SCR) using silver-based catalysts . It is well-known, however, that sulphur oxides (SO x ) are detrimental to the HC-SCR activity on Ag catalysts at temperatures between about 300 and 500 °C [5,[11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Controlling the Sulfur Poisoning of Ag/Al2O3 Catalysts for the Hydrocarbon SCR Reaction by Using a Regenerable SOx Trap

2013

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The deactivation of a silver-based hydrocarbon selective catalytic reduction catalyst by SO x and the subsequent regeneration under various operating conditions has been investigated. Using a sulfur trap based on a silicasupported catalyst it was found that, for a Ag/SiO 2 + Ag/Al 2 O 3 combination, the negative effect of SO 2 on the noctane-SCR reaction can be eliminated under normal operating conditions. The trap can be regenerated by hydrogen at low temperatures or at higher temperatures using a hydrocarbon reductant.

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A comparison of the activity and deactivation of Ag/Al2O3 and Cu/ZSM-5 for HC-SCR under simulated diesel exhaust emission conditions

Cited by 64 publications

References 21 publications

Influence of Mg Addition on the Catalytic Activity of Alumina Supported Ag for C3H6-SCR of NO

Influence of Mg Addition on the Catalytic Activity of Alumina Supported Ag for C3H6-SCR of NO

Review of Ag/Al2O3-Reductant System in the Selective Catalytic Reduction of NO x

Controlling the Sulfur Poisoning of Ag/Al2O3 Catalysts for the Hydrocarbon SCR Reaction by Using a Regenerable SOx Trap

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