Promotional effect of iron oxide on the catalytic properties of Fe–MnO<sub>x</sub>/TiO<sub>2</sub> (anatase) catalysts for the SCR reaction at low temperatures

Deng, Shengcai; Zhuang, Ke; Xu, Bo; Ding, Yuanhua; Yu, Lei; Fan, Yining

doi:10.1039/c5cy01217a

Cited by 57 publications

(36 citation statements)

References 49 publications

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“…As observed, different peaks related with the reduction of iron and manganese species appear in all the TPR profiles. The assignment of these peaks is not easy as the reduction of manganese oxides takes place in a sequential mode where MnO 2 is reduced to Mn 2 O 3 , then to Mn 3 O 4 and finally to MnO, overlapping the different peaks [37][38][39]. According to the literature [40][41][42] the peak at lowest temperature corresponds to the reduction of MnO 2 /Mn 2 O 3 to Mn 3 O 4 and the second peak corresponds to the successive reduction of Mn 3 O 4 to MnO.…”

Section: Resultsmentioning

confidence: 99%

The Influence of the Support on the Activity of Mn–Fe Catalysts Used for the Selective Catalytic Reduction of NOx with Ammonia

2020

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Mono and bimetallic Mn–Fe catalysts supported on different materials were prepared and their catalytic performance in the NH3–SCR of NOx was investigated. It was shown that Mn and Fe have a synergic effect that enhances the activity at low temperature. Nevertheless, the activity of the bimetallic catalysts depends very much on the support selected. The influence of the support on the catalyst activity has been studied using materials with different textural and acid–base properties. Microporous (BEA-zeolite), mesoporous (SBA15 and MCM41) and bulk (metallic oxides) materials with different acidity have been used as supports for the Mn–Fe catalysts. It has been shown that the activity depends on the acidity of the support and on the surface area. Acid sites are necessary for ammonia adsorption and high surface area produces a better dispersion of the active sites resulting in improved redox properties. The best results have been obtained with the catalysts supported on alumina and on beta zeolite. The first one is the most active at low temperatures but it presents some reversible deactivation in the presence of water. The Mn–Fe catalyst supported on beta zeolite is the most active at temperatures higher than 350 °C, without any deactivation in the presence of water and with a 100% selectivity towards nitrogen.

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Section: Resultsmentioning

confidence: 99%

The Influence of the Support on the Activity of Mn–Fe Catalysts Used for the Selective Catalytic Reduction of NOx with Ammonia

2020

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“…Typically, the two distinct peaks at lower (150-250°C) and higher (350-500°C) temperatures are attributed to NH 3 adsorbed on the weak and strong acid sites, respectively. [38] The suitable amount of acid sites observed on FeCu-ZSM-5 is more beneficial to the SCR reaction, which may further enhance the catalytic activity. [13] After the addition of Cu into HZSM-5, an increase in the amount of medium-strong acid sites and a decrease in the strength of the weak and strong acid sites can be seen in the profile of Cu/ZSM-5.…”

Section: Redox and Acid Properties Of The Catalystsmentioning

confidence: 99%

“…[37] The acidity on the catalyst surface, especially the acid amount and strength of the strong acid sites, is known to be the key factor for the adsorption of NH 3 , which is closely related to the selective reduction of NO. [38] The suitable amount of acid sites observed on FeCu-ZSM-5 is more beneficial to the SCR reaction, which may further enhance the catalytic activity. [39]…”

Section: Redox and Acid Properties Of The Catalystsmentioning

confidence: 99%

Direct Synthesis of Hierarchical FeCu‐ZSM‐5 Zeolite with Wide Temperature Window in Selective Catalytic Reduction of NO by NH₃

Yue

Liu

et al. 2019

ChemCatChem

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In this article, we report a one-pot synthesis strategy to directly synthesize the hierarchical FeCu-ZSM-5 zeolite. Its physicochemical properties were studied by various characterization techniques and catalytic performance was tested in selective catalytic reduction (SCR) of NO with NH 3 as reductant. The characterization results show that: compared with three reference zeolites Fe/ZSM-5, Cu/ZSM-5, and Fe/Cu/ZSM-5 prepared through an incipient wetness impregnation method, the synthesized FeCu-ZSM-5 zeolite exhibits hierarchical micro-mesoporous structures, more Fe 3 + in zeolite framework, and larger isolated Cu 2 + species. Therefore, when used as a catalyst in NH 3 -SCR, the resulting hierarchical FeCu-ZSM-5 catalyst shows better catalytic performance (high NO conversion and N 2 selectivity) in a wide temperature window and higher hydrothermal stability than the three reference catalysts. Our work provides a simple and facile route to prepare the promising NH 3 -SCR catalyst for practical applications in controlling NO x emissions.[a] Dr.

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“…Moreover, in iron containing SCR catalysts, the introduction of Mn could obviously enhance the low-temperature activity, probably due to the fact that synergistic effect between iron and manganese species [18]. It was reported that the MnFe/TiO 2 could improve the activity, stability and SO 2 durability of the SCR catalysts using NH 3 as the reducing agent [19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Byproduct Analysis of SO2 Poisoning on NH3-SCR over MnFe/TiO2 Catalysts at Medium to Low Temperatures

Lee

Bai

2019

Catalysts

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The byproducts of ammonia-selective catalytic reduction (NH3-SCR) process over MnFe/TiO2 catalysts under the conditions of both with and without SO2 poisoning were analyzed. In addition to the NH3-SCR reaction, the NH3 oxidation and the NO oxidation reactions were also evaluated at temperatures of 100–300 °C to clarify the reactions occurred during the SCR process. The results indicated that major byproducts for the NH3 oxidation and NO oxidation tests were N2O and NO2, respectively, and their concentrations increased as the reaction temperature increased. For the NH3-SCR test without the presence of SO2, it revealed that N2O was majorly from the NH3-SCR reaction instead of from NH3 oxidation reaction. The byproducts of N2O and NO2 for the NH3-SCR reaction also increased after increasing the reaction temperature, which caused the decreasing of N2-selectivity and NO consumption. For the NH3-SCR test with SO2 at 150 °C, there were two decay stages during SO2 poisoning. The first decay was due to a certain amount of NH3 preferably reacted with SO2 instead of with NO or O2. Then the catalysts were accumulated with metal sulfates and ammonium salts, which caused the second decay of NO conversion. The effluent N2O increased as poisoning time increased, which was majorly from oxidation of unreacted NH3. On the other hand, for the NH3-SCR test with SO2 at 300 °C, the NO conversion was not decreased after increasing the poisoning time, but the N2O byproduct concentration was high. However, the SO2 led to the formation of metal sulfates, which might inhibit NO oxidation reactions and cause the concentration of N2O gradually decreased as well as the N2-selectivity increased.

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Promotional effect of iron oxide on the catalytic properties of Fe–MnO_x/TiO₂ (anatase) catalysts for the SCR reaction at low temperatures

Abstract: The surface interaction of the iron-improved MnOx/TiO2 (anatase) catalyst for the selective catalytic reduction of nitric oxide was studied. The role of iron was investigated through detailed experiments.

Cited by 57 publications

References 49 publications

The Influence of the Support on the Activity of Mn–Fe Catalysts Used for the Selective Catalytic Reduction of NOx with Ammonia

The Influence of the Support on the Activity of Mn–Fe Catalysts Used for the Selective Catalytic Reduction of NOx with Ammonia

Direct Synthesis of Hierarchical FeCu‐ZSM‐5 Zeolite with Wide Temperature Window in Selective Catalytic Reduction of NO by NH₃

Byproduct Analysis of SO2 Poisoning on NH3-SCR over MnFe/TiO2 Catalysts at Medium to Low Temperatures

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Promotional effect of iron oxide on the catalytic properties of Fe–MnOx/TiO2 (anatase) catalysts for the SCR reaction at low temperatures

Abstract: The surface interaction of the iron-improved MnOx/TiO2 (anatase) catalyst for the selective catalytic reduction of nitric oxide was studied. The role of iron was investigated through detailed experiments.

Cited by 57 publications

References 49 publications

The Influence of the Support on the Activity of Mn–Fe Catalysts Used for the Selective Catalytic Reduction of NOx with Ammonia

The Influence of the Support on the Activity of Mn–Fe Catalysts Used for the Selective Catalytic Reduction of NOx with Ammonia

Direct Synthesis of Hierarchical FeCu‐ZSM‐5 Zeolite with Wide Temperature Window in Selective Catalytic Reduction of NO by NH3

Byproduct Analysis of SO2 Poisoning on NH3-SCR over MnFe/TiO2 Catalysts at Medium to Low Temperatures

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Promotional effect of iron oxide on the catalytic properties of Fe–MnO_x/TiO₂ (anatase) catalysts for the SCR reaction at low temperatures

Direct Synthesis of Hierarchical FeCu‐ZSM‐5 Zeolite with Wide Temperature Window in Selective Catalytic Reduction of NO by NH₃