Low temperature SCR reaction over Nano-Structured Fe-Mn Oxides: Characterization, performance, and kinetic study

Zhang, Changai; Chen, Tianhu; Li, Haibo; Chen, Dong; Xu, Bin; Qing, Chen

doi:10.1016/j.apsusc.2018.07.019

Cited by 86 publications

(38 citation statements)

References 43 publications

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“…The test results were analyzed and compared in Figure 7 and Table 4, respectively. The NH 3 -TPD curves for these three typical Mn-based bimetallic nanocatalysts were attributed to four desorption peaks of chemisorbed NH 3 within the temperature range of 150~750 • C. It was obvious that the first weak NH 3 desorption peak (P1) of Mn−Fe/TiO 2 nanocatalyst appeared at about 209 • C ascribed to the NH 3 desorption from the weak acid sites, which was deemed too weak to be stable bound NH 3 in the gas mix during the SCR reactions [14]. The second and the third successive desorption peaks (P2 and P3) located from 398 • C to 585 • C indicated the distribution of medium strong acid sites.…”

Section: Ammonia Adsorption Propertiesmentioning

confidence: 99%

“…Besides the redox property, the acid capacity on the catalyst surface was another crucial factor influencing the catalytic performance in SCR reactions [14,38]. NH 3 -TPD and NO-TPD tests were introduced in order to establish the connection between the surface acidities and the SCR activities for the Mn-based bimetallic nanocatalysts.…”

Section: Ammonia Adsorption Propertiesmentioning

confidence: 99%

“…Each experiment was repeated three times to assure the results accuracy. The discharge energy density was defined as discharge power divided by the inlet gas flow rate [9], which was calculated using Equation (14) [60], where E (W·h/m 3 ) was energy density, P (W) was discharge power, and Q (m 3 /h) was the gas flow rate. More basic data relating to the discharge energy was listed in Table 1.…”

Section: Catalytic Performance Testsmentioning

confidence: 99%

“…Among the various transition metal elements applied in the catalysts for NO x reduction, manganese displays superior activity especially at the low temperature, which can be attributed to the multifarious types of labile oxygen and high mobility of valence states [1]. Meanwhile, it has been found that iron, cobalt, and cerium species can combine with manganese to produce bimetallic catalysts, which contain abundant oxygen vacancies on the catalyst surface, forming strong interaction bands at atomic scale, such as Mn-O-Fe [14], Mn-O-Co [15], and Mn-O-Ce [16]. Moreover, the active metal species of FeO x , CoO x , and CeO x are also regarded as the three typical promoters for NO x conversion, which serve as core catalyst components of active metal oxides, supplying surface oxygen to accelerate NO x elimination [14,15,17].…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, it has been found that iron, cobalt, and cerium species can combine with manganese to produce bimetallic catalysts, which contain abundant oxygen vacancies on the catalyst surface, forming strong interaction bands at atomic scale, such as Mn-O-Fe [14], Mn-O-Co [15], and Mn-O-Ce [16]. Moreover, the active metal species of FeO x , CoO x , and CeO x are also regarded as the three typical promoters for NO x conversion, which serve as core catalyst components of active metal oxides, supplying surface oxygen to accelerate NO x elimination [14,15,17]. However, the effects of Mn-based bimetallic catalysts on the plasma-catalyst hybrid catalysis, especially the Mn−Fe/TiO 2 , Mn−Co/TiO 2 , and Mn−Ce/TiO 2 nanocatalysts have not been explored clearly.…”

Section: Introductionmentioning

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: Ammonia Adsorption Propertiesmentioning

confidence: 99%

Section: Ammonia Adsorption Propertiesmentioning

confidence: 99%

Section: Catalytic Performance Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

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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Enhancing low‐temperature SCR deNOx MnCe catalyst based on rice husk char by KOH and H₃PO₄ activation

Liu

Zhao

et al. 2021

J of Chemical Tech & Biotech

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BACKGROUND: It is of great significance industrially to find cheap materials as low-temperature selective catalytic reduction (SCR) catalyst support. Pyrolyzed rice husk char (RC) is not only cheap, but also has the characteristics of high porosity, large SSA and good adsorption. Therefore, there is emerging interest in RC as an SCR support. The present contribution is a comparative study of low-temperature SCR manganese-cerium (Mn Ce) catalysts based on RC activated by potassium hydroxide (KOH) and phosphoric acid (H 3 PO 4 ), revealing the different mechanisms of improvement in catalytic performance.RESULTS: Mn-Ce/RCK (catalyst of Mn Ce loaded on KOH activated RC) has a wider activity temperature window in the range 120-260 °C, while Mn-Ce/RCP (catalyst of Mn Ce loaded on H 3 PO 4 activated RC) can reach the highest NO conversion of 97% at 240 °C.CONCLUSIONS: N 2 adsorption-desorption, Fourier transform infrared (FTIR), X-ray diffraction (XRD), NH 3 -temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) were used to characterize and analyze their catalytic performance. The N 2 adsorption-desorption and NH 3 -TPD showed that Mn-Ce/RCK has a larger SSA and more acid sites than those of Mn-Ce/RC and Mn-Ce/RCP. XRD indicated that Mn-Ce/RCP has a better dispersion than that of Mn-Ce/RCK. FTIR showed that Mn-Ce/RCP had more oxygen (O)-containing functional groups. The XPS revealed that Mn-Ce/RCP has higher ratios of Mn 4+ , Ce 3+ and O ⊎ .

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Comparative study on K‐tolerance performance of Fe/ZrO₂ and Fe/ZrO₂‐W catalysts for NH₃‐SCR of NO_x

Han

et al. 2023

J of Chemical Tech & Biotech

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BACKGROUND: Selective catalytic reduction (SCR) of nitrous oxides (NO x ) with ammonia (NH 3 ) as reductant is used worldwide in mobile and stationary sources to reach strict emission standards. It is a feasible strategy to modify support with acidic metal oxides to improve the alkali metal potassium (K) tolerance of SCR catalysts. Herein, a comparative investigation was conducted based on iron/zirconium dioxide (Fe/ZrO 2 )and Fe/ZrO 2 -tungsten (W) catalysts to reveal the correlation of support modification with W and K-tolerance performance. RESULTS: The NO x conversion for K-Fe/ZrO 2 catalyst was <80% across the whole temperature range, and the catalyst was completely deactivated at ≈400 °C. As expected, the Fe/ZrO 2 -W catalyst exhibited a much superior anti-K-performance in comparison to the Fe/ZrO 2 catalyst. The active temperature window for K-Fe/ZrO 2 -W catalyst was 285-485 °C (NO x conversion of >80%).CONCLUSION: According to the characterization results, it was found that K-species impose a negative impact on NH 3 adsorption on the surface of the Fe/ZrO 2 catalyst, especially drastically preventing the adsorption of NH 3 species on Brønsted acid sites, thus inhibiting the occurrence of SCR reactions via the Langmuir-Hinshelwood (L-H) mechanism. By contrast, W modification resulted in more chemisorbed oxygen, stronger redox capacity and an increased Fe 3+ /(Fe 3+ +Fe 2+ ) ratio on the surface of the Fe/ZrO 2 -W catalyst. More importantly, W modification brought about abundant Brønsted acid sites, significantly promoting NH 3 adsorption and activation. W modification also weakened the adsorption stability of NO x species to a certain extent. As a result, SCR reactions over the Fe/ZrO 2 -W catalyst could proceed via both Eley-Rideal (E-R) and L-H pathways.

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Low temperature SCR reaction over Nano-Structured Fe-Mn Oxides: Characterization, performance, and kinetic study

Cited by 86 publications

References 43 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

Enhancing low‐temperature SCR deNOx MnCe catalyst based on rice husk char by KOH and H₃PO₄ activation

Comparative study on K‐tolerance performance of Fe/ZrO₂ and Fe/ZrO₂‐W catalysts for NH₃‐SCR of NO_x

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Low temperature SCR reaction over Nano-Structured Fe-Mn Oxides: Characterization, performance, and kinetic study

Cited by 86 publications

References 43 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

Enhancing low‐temperature SCR deNOx MnCe catalyst based on rice husk char by KOH and H3PO4 activation

Comparative study on K‐tolerance performance of Fe/ZrO2 and Fe/ZrO2‐W catalysts for NH3‐SCR of NOx

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Enhancing low‐temperature SCR deNOx MnCe catalyst based on rice husk char by KOH and H₃PO₄ activation

Comparative study on K‐tolerance performance of Fe/ZrO₂ and Fe/ZrO₂‐W catalysts for NH₃‐SCR of NO_x