Effects of surface physicochemical properties on NH3-SCR activity of MnO2 catalysts with different crystal structures

Gong, Pijun; Xie, Jun; Fang, De; Han, De‐hua; He, Feng; Li, Fengxiang; Qi, Kai

doi:10.1016/s1872-2067(17)62922-x

Cited by 65 publications

(28 citation statements)

References 67 publications

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“…For Mn−Ce/TiO 2 nanocatalyst, as shown in Figure 6a, there were five main H 2 consumption peaks appearing within the temperature range of 50~850 • C. The initial dominating reduction peak (R1) at around 261 • C was mainly caused by the reduction reaction of the high oxidation state of Mn 4+ reducing to Mn 3+ [32]. The subsequent asymmetrical reduction peak from 260 • C to 410 • C could be further divided into two reduction peaks (R2 and R3), according to the two processes of Mn 2 O 3 reducing to Mn 3 O 4 and Mn 2 O 3 reducing to MnO reported in previous literatures [28,31]. The converting from Mn 2 O 3 to Mn 3 O 4 preferred to occur on the primal amorphous Mn 2 O 3 [33], which was consistent with appearance of R2 peak.…”

Section: Reducibility Propertiesmentioning

confidence: 68%

“…The initial dominating reduction peak (R1) at 333 around 261 °C was mainly caused by the reduction reaction of the high oxidation state of Mn 4+ 334 reducing to Mn 3+ [32]. The subsequent asymmetrical reduction peak from 260 °C to 410 °C could be 335 further divided into two reduction peaks (R2 and R3), according to the two processes of Mn2O3 336 reducing to Mn3O4 and Mn2O3 reducing to MnO reported in previous literatures [28,31]. The…”

Section: Tem Analysismentioning

confidence: 73%

“…On account of the 327 support of anatase TiO2 induced no noteworthy reduction peaks in the test temperature region, all 328 the H2 consumption peaks displayed in Figure 6 could be ascribed to the reduction reactions of 329 diverse active species of MnOx, CeOx, CoOx, and FeOx. For Mn-based catalysts, the typical reduction 330 peaks were regard as following the order of MnO2 → Mn2O3 (Mn3O4) → MnO [31]. For appearing within the temperature range of 50~850 °C.…”

Section: Tem Analysismentioning

confidence: 99%

“…On account of the support of anatase TiO 2 induced no noteworthy reduction peaks in the test temperature region, all the H 2 consumption peaks displayed in Figure 6 could be ascribed to the reduction reactions of diverse active species of MnO x , CeO x , CoO x , and FeO x . For Mn-based catalysts, the typical reduction peaks were regard as following the order of MnO 2 → Mn 2 O 3 (Mn 3 O 4 ) →MnO [31]. For Mn−Ce/TiO 2 nanocatalyst, as shown in Figure 6a, there were five main H 2 consumption peaks appearing within the temperature range of 50~850 • C. The initial dominating reduction peak (R1) at around 261 • C was mainly caused by the reduction reaction of the high oxidation state of Mn 4+ reducing to Mn 3+ [32].…”

Section: Reducibility Propertiesmentioning

confidence: 99%

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High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species

et al. 2019

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Three typical Mn-based bimetallic nanocatalysts of Mn−Fe/TiO2, Mn−Co/TiO2, Mn−Ce/TiO2 were synthesized via the hydrothermal method to reveal the synergistic effects of dielectric barrier discharge (DBD) plasma and bimetallic nanocatalysts on NOx catalytic conversion. The plasma-catalyst hybrid catalysis was investigated compared with the catalytic effects of plasma alone and nanocatalyst alone. During the catalytic process of catalyst alone, the catalytic activities of all tested catalysts were lower than 20% at ambient temperature. While in the plasma-catalyst hybrid catalytic process, NOx conversion significantly improved with discharge energy enlarging. The maximum NOx conversion of about 99.5% achieved over Mn−Ce/TiO2 under discharge energy of 15 W·h/m3 at ambient temperature. The reaction temperature had an inhibiting effect on plasma-catalyst hybrid catalysis. Among these three Mn-based bimetallic nanocatalysts, Mn−Ce/TiO2 displayed the optimal catalytic property with higher catalytic activity and superior selectivity in the plasma-catalyst hybrid catalytic process. Furthermore, the physicochemical properties of these three typical Mn-based bimetallic nanocatalysts were analyzed by N2 adsorption, Transmission Electron Microscope (TEM), X-ray diffraction (XRD), H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The multiple characterizations demonstrated that the plasma-catalyst hybrid catalytic performance was highly dependent on the phase compositions. Mn−Ce/TiO2 nanocatalyst presented the optimal structure characteristic among all tested samples, with the largest surface area, the minished particle sizes, the reduced crystallinity, and the increased active components distributions. In the meantime, the ratios of Mn4+/(Mn2+ + Mn3+ + Mn4+) in the Mn−Ce/TiO2 sample was the highest, which was beneficial to plasma-catalyst hybrid catalysis. Generally, it was verified that the plasma-catalyst hybrid catalytic process with the Mn-based bimetallic nanocatalysts was an effective approach for high-efficiency catalytic conversion of NOx, especially at ambient temperature.

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Section: Reducibility Propertiesmentioning

confidence: 68%

Section: Tem Analysismentioning

confidence: 73%

Section: Tem Analysismentioning

confidence: 99%

Section: Reducibility Propertiesmentioning

confidence: 99%

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High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species

et al. 2019

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“…In comparison with pure γ-Al2O3, the surface area of the γ-Al2O3 loaded with Mo which was due to its low content. Pijun Gong's et al [37] claimed that β-MnO2 has the worst SCR activity in among different MnO2 species, while α-Mn2O3 was found to demonstrate high SCR activity and selectivity by many researchers [38,39]. Except for γ-Al2O3, the intensity of diffraction…”

Section: Effects Of Mo Addition On Mn Dispersionmentioning

confidence: 99%

Promotion effect and mechanism of the addition of Mo on the enhanced low temperature SCR of NOx by NH3 over MnOx/γ-Al2O3 catalysts

Yang

Zhao

Luo

et al. 2019

Applied Catalysis B: Environmental

119

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A series of Mn/γ-Al2O3 and MnMo/γ-Al2O3 catalysts were prepared by using Incipient Wetness Impregnation (IWI) method. The catalytic performance tests showed that the Mn3Mo1.25/γ-Al2O3 demonstrated a higher SCR performance (NO conversion of around 96%) at a broad low temperature range (150 to 300°C). The characterization showed that the addition of Mo to the Mn/γ-Al2O3 catalysts could promote the dispersion of MnOx on the surface of γ-Al2O3. The adsorption of NO could form two different species, nitrites and nitrates on the surface of the catalyst. The presence of nitrites is beneficial to low temperature SCR. It is also found that the existence of Mo in the catalyst favours the formation of Mn 3+ , which plays a critical role in the adsorption of NH3 and therefore improves NH3 adsorption capacity of the MnOx/γ-Al2O3 catalysts. The low temperature SCR of the Mn3Mo1.25/γ-Al2O3 catalyst was found to mainly follow L-H mechanism, but E-R mechanism also plays a role to some extent. Moreover, it is also found that the addition of Mo not only mitigates the deactivation of catalysts, but also broadens the effective temperature range of the SCR catalyst.

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Highly Effective Non‐Noble MnO₂ Catalysts for 5‐Hydroxymethylfurfural Oxidation to 2,5‐Furandicarboxylic Acid

Álvarez‐Hernández,

Megías‐Sayago,

Penkova

et al. 2024

ChemSusChem

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Noble metal‐free catalyst or catalytic oxidation of 5‐hydroxymethylfurfural into 2,5‐furandicarboxylic acid are proposed in this study as a proposal to solve one of the great disadvantages of this reaction of using preferably noble metal‐based catalysts. The catalytic activity of six MnO2 crystal structures is studied as alternative. The obtained results showed a strong connection between catalytic activity the type of MnO2 structure organization and redox behavior. Among all tested catalysts, ε‐MnO2 showed the best performance with an excellent yield of 74% of 2,5‐furandicarboxylic acid at full –hydroxymethylfurfural conversion.

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Effects of surface physicochemical properties on NH3-SCR activity of MnO2 catalysts with different crystal structures

Cited by 65 publications

References 67 publications

High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species

High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species

Promotion effect and mechanism of the addition of Mo on the enhanced low temperature SCR of NOx by NH3 over MnOx/γ-Al2O3 catalysts

Highly Effective Non‐Noble MnO₂ Catalysts for 5‐Hydroxymethylfurfural Oxidation to 2,5‐Furandicarboxylic Acid

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Effects of surface physicochemical properties on NH3-SCR activity of MnO2 catalysts with different crystal structures

Cited by 65 publications

References 67 publications

High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species

High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species

Promotion effect and mechanism of the addition of Mo on the enhanced low temperature SCR of NOx by NH3 over MnOx/γ-Al2O3 catalysts

Highly Effective Non‐Noble MnO2 Catalysts for 5‐Hydroxymethylfurfural Oxidation to 2,5‐Furandicarboxylic Acid

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Highly Effective Non‐Noble MnO₂ Catalysts for 5‐Hydroxymethylfurfural Oxidation to 2,5‐Furandicarboxylic Acid