Investigation on the catalytic roles of silver species in the selective catalytic reduction of NO with methane

Shi, Chuan; Cheng, Mojie; Qu, Zhenping; Bao, Xinhe

doi:10.1016/j.apcatb.2003.12.003

Cited by 63 publications

(37 citation statements)

References 37 publications

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“…Peaks 99 and 193 8C are originated from the adsorbed NO species, and the peaks 367 and 370 8C (shown in Figure 11a and b) are due to the produced NO and O 2 from the decomposition of adsorbed NO x (x = 2 or 3) species at elevated temperatures, respectively. [30][31][32] For CO À CuMnAl catalyst, the NO desorption profiles are also composed of three peaks: a principal peak at low temperature (84 8C) with a shoulder at 150 8C and a weak NO desorption peak at higher temperature (210 8C), as shown in Figure 11a. It should be noted that the desorption peak temperature of NO over COÀCuMnAl catalyst is obviously lower than that over the CuMnAl catalyst, which implies that CO À CuMnAl catalyst has higher NO dissociation activity than that of CuMnAl catalyst.…”

Section: Resultsmentioning

confidence: 98%

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

et al. 2011

Chemistry A European J

120

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NO reduction by CO was investigated over CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuOMn2O3/γ-Al2O3 model catalysts before and after CO pretreatment at 300 °C. The CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst exhibited higher catalytic activity than did the other catalysts. Based on X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis diffuse reflectance spectroscopy (DRS), Raman, and H2-temperature-programmed reduction (TPR) results, as well as our previous studies, the possible interaction model between dispersed copper and manganese oxide species as well as γ-Al2O3 surface has been proposed. In this model, Cu and Mn ions occupied the octahedral vacant sites of γ-Al2O3, with the capping oxygen on top of the metal ions to keep the charge conservation. For the fresh CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, the -Cu-O-Cu- and -Mn-O-Mn- species were formed on the surface of γ-Al2O3, respectively; but for the fresh CuO-Mn2O3/γ-Al2O3 catalyst, -Cu-O-Mn- species existed on the surface of -Al2O3. After CO pretreatment, -Cu-□-Cu- and -Mn-□-Mn- (□ represents surface oxygen vacancy (SOV)) species would be formed in CO-pretreated CuO/γ-Al2O3 and CO-pretreated Mn2O3/γ-Al2O3 catalysts, respectively; whereas -Cu-□-Mn- species existed in CO-pretreated CuO-Mn2O3/γ-Al2O3. Herein, a new concept, surface synergetic oxygen vacancy (SSOV), which describes the oxygen vacancy formed between the individual Mn and Cu ions, is proposed for CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst. In addition, the role of SSOV has also been approached by NO temperature-programmed desorption (TPD) and in situ FTIR experiments. The FTIR results of competitive adsorption between NO and CO on all the CO-pretreated CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuO-Mn2O3/γ-Al2O3 samples demonstrated that NO molecules mainly were adsorbed on Mn2+ and CO mainly on Cu+ sites. The current study suggests that the properties of the SSOVs in CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst were significantly different to SOVs formed in CO-pretreated CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, and the SSOVs played an important role in NO reduction by CO.

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Section: Resultsmentioning

confidence: 98%

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

et al. 2011

Chemistry A European J

120

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“…Recently, silver has received much attention as a suitable catalyst for many redox reactions such as low temperature NO x reduction [13], CH 4 oxidation [14,15], CO oxidation [15,16], and oxidation of VOCs [17][18][19][20]. Cordi and Falconer [17] observed that Ag/Al 2 O 3 catalyst was very active for the complete oxidation of VOCs.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Combustion of Toluene over a Copper‐Manganese‐Silver Mixed‐Oxide Catalyst Supported on a Washcoated Ceramic Monolith

Zhou

Jiang

et al. 2009

Chem Eng & Technol

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Monolithic catalysts were prepared by washcoating an alumina sol and then impregnating Cu-Mn-Ag mixed oxides onto cordierite substrates. The effects of the preparation parameters including the Ag/Cu/Mn ratio, the total amount of active phase and the loading of washcoat, and the reaction conditions, e.g., the space velocity and the oxygen/toluene ratio on the catalytic performance for the combustion of toluene were investigated. It is shown that the Cu-Mn-Ag oxides are very active for the combustion of toluene and that the highest catalytic activity is achieved over a monolithic catalyst containing 14.7 wt % of washcoat and 21.2 wt % of active phase with a Ag/Cu/Mn molar ratio of 13.8/43.1/43.1. It is also seen that the optimum catalyst has a good catalytic stability and exhibits an excellent activity not only at a rather high space velocity but also within a wide range of oxygen/toluene ratios.

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“…[1][2][3][4] Moreover, their high surface-to-volume ratio renders them ideal candidates for application as catalysts. [5][6][7][8][9] However, the pronounced tendency of nanoparticles to aggregate must be overcome by using suitable carrier systems. Recently, a number of systems have been discussed that are suitable for applications in aqueous environments.…”

mentioning

confidence: 99%

Thermosensitive Core–Shell Particles as Carriers for Ag Nanoparticles: Modulating the Catalytic Activity by a Phase Transition in Networks

et al. 2006

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Nanoreactors: Metal nanoparticles must be stabilized with carrier systems against aggregation if they are to have applications in catalysis. One such system, a thermosensitive network of poly(N‐isopropylacrylamide) that surrounds a polystyrene core, enables control over the catalytic activity of the nanoparticles through a phase transition and leads to applications as a controllable nanoreactor.

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Investigation on the catalytic roles of silver species in the selective catalytic reduction of NO with methane

Cited by 63 publications

References 37 publications

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

Catalytic Combustion of Toluene over a Copper‐Manganese‐Silver Mixed‐Oxide Catalyst Supported on a Washcoated Ceramic Monolith

Thermosensitive Core–Shell Particles as Carriers for Ag Nanoparticles: Modulating the Catalytic Activity by a Phase Transition in Networks

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Investigation on the catalytic roles of silver species in the selective catalytic reduction of NO with methane

Cited by 63 publications

References 37 publications

The Remarkable Enhancement of CO‐Pretreated CuOMn2O3/γ‐Al2O3 Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

The Remarkable Enhancement of CO‐Pretreated CuOMn2O3/γ‐Al2O3 Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

Catalytic Combustion of Toluene over a Copper‐Manganese‐Silver Mixed‐Oxide Catalyst Supported on a Washcoated Ceramic Monolith

Thermosensitive Core–Shell Particles as Carriers for Ag Nanoparticles: Modulating the Catalytic Activity by a Phase Transition in Networks

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The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy