Influence of zeolite support on activity enhancement by addition of hydrogen for SCR of NO by propane over Ag-zeolites

Shibata, Junji; Takada, Yasunobu; Shichi, Akira; Satokawa, Shigeo; Satsuma, Atsushi; Hattori, Tadashi

doi:10.1016/j.apcatb.2004.03.005

Cited by 67 publications

(66 citation statements)

References 34 publications

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“…A recent study found that addition of H 2 to feed stream could result in a remarkable improvement in the activity of NO x reduction and the active temperature range [6]. Furthermore, the positive effect of H 2 is found to be specific for silver catalysts such as Ag/Al 2 O 3 [6][7][8] and Ag-zeolites [9][10][11]. The effect of H 2 for the SCR of NO x over Ag/Al 2 O 3 catalyst has been investigated with several alkanes (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Using in situ FTIR spectroscopy, the promotional effect of H 2 on the oxidation of NO to NO 2 and the oxidation of hydrocarbons to acetates has been revealed on Ag/Al 2 O 3 [12][13][14]. Instead of NO oxidation, Shibata et al [9][10][11] proposed that the positive effect of H 2 addition on the NO x reduction was attributed to the formation of small charged metallic Ag n d+ clusters based on the results of UV-vis spectroscopy. Burch and Breen et al [15,16] postulated that the improvement of added H 2 in the SCR of NO x was due to the formation of C N species, and was not associated with significant structural changes in the Ag/Al 2 O 3 catalyst at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Effect of hydrogen on reaction intermediates in the selective catalytic reduction of NOx by C3H6

Zhang

2007

Applied Catalysis B: Environmental

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Selective catalytic reduction of NO x by C 3 H 6 in the presence of H 2 over Ag/Al 2 O 3 was investigated using in situ DRIFTS and GC-MS measurements. The addition of H 2 promoted the partial oxidation of C 3 H 6 to enolic species, the formation of -NCO and the reactions of enolic species and -NCO with NO x on Ag/Al 2 O 3 surface at low temperatures. Based on the results, we proposed reaction mechanism to explain the promotional effect of H 2 on the SCR of NO x by C 3 H 6 over Ag/Al 2 O 3 catalyst. #

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of hydrogen on reaction intermediates in the selective catalytic reduction of NOx by C3H6

Zhang

2007

Applied Catalysis B: Environmental

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“…Whereas, Brönsted acids have been suggested to be essential for HC-SCR over many catalytic systems (e.g. ZSM-5 modified by Pd, Ga, In, Ce and Ag) [11][12][13][14][15][16][17][18]. The authors found that Brönsted acids contributed to the aimed reaction in different steps.…”

Section: Introductionmentioning

confidence: 91%

Effect of Sodium in Ferrierite on Selective Catalytic Reduction of NO by Acetylene

et al. 2008

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Influence of sodium in ferrierite (HFER) zeolite on selective catalytic reduction of NO by acetylene (C 2 H 2 -SCR) was investigated. NO x -TPD and FT-IR indicated that small amount of sodium exchanged into the proton-form zeolite with an exchange level of about 11.8% is beneficial for the title reaction by accelerating active nitrate species formation on catalyst surface from NO 2 and by suppressing the reductant combustion. Nevertheless, no further improved catalytic performance in C 2 H 2 -SCR could be observed by a larger amount of sodium exchanged into HFER due to some inactive nitrate species formed on the zeolite. Instead, activity of the zeolite for C 2 H 2 -SCR was drastically reduced, since the capacity of the zeolite for catalyzing NO oxidation and accelerating active NO + species formation was remarkably depressed.

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“…No significant modifying effect of La 3＋ ions could be observed, which is quite different from Ce 3＋ ions, though they exhibit a similar electronic structure. Some transition metal ions, such as Mn 2＋ , 17 Fe 3＋ , 18 Co 2＋ , 19 Cu 2＋ 20 and Ag ＋ , 21 have been extensively investigated and reported as better promoters for the HC-SCR. However, no more appreciated doping effect was observed than Ce 3＋ when they were exchanged into HY, even though Ag ＋ yielded the highest efficiency at 300 ℃ among them.…”

Section: Catalytic Performance Of Various M-hy In the C 2 H 2 -Scr Ofmentioning

confidence: 99%

Using Acetylene for Selective Catalytic Reduction of NO in Excess Oxygen

Wang

et al. 2006

Chin. J. Chem.

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Acetylene as a reducing agent for selective catalytic reduction of NO (C 2 H 2 -SCR) was investigated over a series of metal exchanged HY catalysts, in the reaction system of 0.16% NO, 0.08% C 2 H 2 , and 9.95% O 2 (volume percent) in He. 75% of NO conversion to N 2 with hydrocarbon efficiency about 1.5 was achieved over a Ce-HY catalyst around 300 ℃. The NO removal level was comparable with that of selective catalytic reduction of NO x by C 3 H 6 reported in literatures, although only one third of the reducing agent in carbon moles was used in the C 2 H 2 -SCR of NO. The protons in zeolite were crucial to the C 2 H 2 -SCR of NO, and the performance of HY in the reaction was significantly promoted by cerium incorporation into the zeolite. NO 2 was proposed to be the intermediate of NO reduction to N 2 , and the oxidation of NO to NO 2 was rate-determining step of the C 2 H 2 -SCR of NO over Ce-HY. The suggestion was well supported by the results of the NO oxidation with O 2 , and the C 2 H 2 consumption under the conditions in the presence or absence of NO.

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Influence of zeolite support on activity enhancement by addition of hydrogen for SCR of NO by propane over Ag-zeolites

Cited by 67 publications

References 34 publications

Effect of hydrogen on reaction intermediates in the selective catalytic reduction of NOx by C3H6

Effect of hydrogen on reaction intermediates in the selective catalytic reduction of NOx by C3H6

Effect of Sodium in Ferrierite on Selective Catalytic Reduction of NO by Acetylene

Using Acetylene for Selective Catalytic Reduction of NO in Excess Oxygen

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