Investigation of Low-Temperature Selective Catalytic Reduction of NOx with Ammonia over Mn-Modified Fe2O3/AC Catalysts

Chen, Jiuyu; Zhu, Bin; Song, Yin; Zhu, Zicheng; Li, Jiaxin

doi:10.21577/0103-5053.20170116

Cited by 19 publications

(28 citation statements)

References 16 publications

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“…The reduction peak of AC at 650°C was attributed to the reduction of oxygen‐containing functional groups . Pure Fe 2 O 3 displayed two reduction peaks, which are assigned to the stepwise reduction from Fe 3+ to Fe 2+ at 364°C and Fe 3 O 4 to FeO at 588°C . There were considerable differences in the H 2 ‐TPR profiles of 6Fe/AC and 8Mn6Fe/AC catalysts.…”

Section: Resultsmentioning

confidence: 98%

“…Carbon‐based materials (such as activated carbon and activated coke [AC]) have the advantages of large surface area, strong adsorption capacity, low cost, and high stability, and the carbon‐based material with well‐developed porous structure is beneficial for the SCR denitration performance at low temperatures . Compared with activated carbon, AC as the supporter of SCR denitration catalyst has high mechanical strength, wear resistance, and unique pore structure . In addition, its price is cheaper than that of activated carbon.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism

Song

Zhu

Sun

et al. 2018

Asia-Pacific J Chem Eng

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Fe2O3/activated coke (AC) and Mn–Fe2O3/AC catalysts were prepared by an impregnation method for the low‐temperature selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3). These catalysts were characterized by X‐ray fluorescence, X‐ray diffraction, isothermal N2 adsorption/desorption, X‐ray photoelectron spectroscopy, temperature program reduction by H2, and temperature programmed desorption of NH3 methods. Experimental results show that Fe2O3/AC catalyst with Mn addition exhibits an excellent NOx conversion at low temperature. Nearly more than 94.7% NOx conversion of 8Mn6Fe/AC catalyst was obtained at 180–240°C. The results of NH3 transient reaction and adsorption capacity of NOx indicate that 8Mn6Fe/AC catalyst has the capacity to adsorb gaseous NH3 and NOx on the catalyst surface. 6Fe/AC catalyst with a certain amount addition of Mn increases the dispersion of γ‐Fe2O3 phase, and ratios of Fe3+/(Fe2+ + Fe3+) and Oβ/(Oβ + Oα) obtained good reducibility and a lot of acid sites, which play important roles in improving the NOx conversion. The influences of SO2 and H2O on the NOx conversion over 8Mn6Fe/AC catalyst were also investigated. The good H2O poisoning resistance was obtained.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism

Song

Zhu

Sun

et al. 2018

Asia-Pacific J Chem Eng

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“…32 The simulated mixed flue gas comprised 500 ppm NO, 500 ppm NH 3 , 5 vol% O 2 and was balanced with N 2 . The total gas flow rate of the mixed flue gas was 100 mL min -1 and the gas hourly space velocity (GHSV) was 13000 h -1 .…”

Section: Catalytic Experimentsmentioning

confidence: 99%

De-NOx Performance and Mechanism of Mn-Based Low-Temperature SCR Catalysts Supported on Foamed Metal Nickel

Zhu

Song

et al. 2018

J. Braz. Chem. Soc.

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A series of manganese-based catalysts supported on foamed metal nickel (FMN) with various Mn/Ni ratios was prepared for low-temperature selective catalytic reduction (SCR) of NO with NH 3 (NH 3 -SCR). The effects of calcination temperature, amount of added Mn, optimal operating conditions, and H 2 O on the elimination of nitrogen oxides (de-NO x ) performance of catalysts were studied. The catalysts were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-programmed desorption experiments of NH 3 analyses. The experimental results revealed that the Mn 7.5 /FMN catalyst calcined at 350 °C exhibited the best NO conversion that was ca. 100% at 120-200 °C. Moreover, it had excellent H 2 O tolerance. The superior activity of the Mn 7.5 /FMN catalyst, which was calcined at 350 °C, was attributed to the presence of amorphous manganese oxide, more unsaturated Ni atoms and structural defects, an increase in NH 3 adsorbance, and the number of surface acid sites. Based on these studies, we established that the reaction of the NH 3 -SCR with Mn 7.5 /FMN catalyst mainly exhibits an Eley-Rideal mechanism.Keywords: de-NO x , low-temperature SCR, MnO x , foamed metal nickel, mechanism IntroductionNitrogen oxides (NO x ) such as NO and NO 2 resulting from fossil fuel combustion are one of the main pollutants in the atmosphere. NO x gases are responsible for acid rain, photochemical smog, and ozone layer depletion. At high levels, they affect the respiratory system, and long-term exposure can damage lung function.1-3 Currently, several methods are used to eliminate NO x (de-NO x ). Selective catalytic reduction (SCR) of NO with NH 3 (NH 3 -SCR) is one of the most effective ways to reduce NO x emissions. [4][5][6][7][8] The reactions are as follows: As a core link in this technology, the catalyst performance directly affects the de-NO x efficiency of the whole SCR system. 9,10 The V 2 O 5 -WO 3 (MoO 3 )/TiO 2 catalyst is a commonly used commercial SCR catalyst for NO x removal with an active temperature range of 300-400 °C. 11,12 However, this catalyst has many disadvantages including the toxicity of vanadium at high temperatures.13 Therefore, significant efforts should be devoted towards the development of non-vanadium catalysts for NH 3 -SCR processes. Mn-based catalysts have been studied due to their inherent environmentfriendly characteristics and excellent SCR activity at low temperatures. [14][15][16][17][18][19] Zhu et al. 1681 Vol. 29, No. 8, 2018 co-workers 22 studied the low-temperature de-NO x activity of Mn-Ce/TiO 2 and Mn-Ce/Al 2 O 3 catalysts. The results indicated that the de-NO x performance of the Mn-Ce/TiO 2 catalyst was better than that of the Mn-Ce/Al 2 O 3 catalyst at temperatures of 80-150 °C. Although the Mn-based catalysts exhibit high low-temperature activities, there are significant differences in their low-temperature SCR activity. [23][24][25] Moreover, the role of the carrier should not be ignored. 26,27 Foamed metal nickel (FMN) with...

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“…Activated carbon fibre (ACF), as one flexible material, constitutes an excellent catalyst support owing to its developed micropore structure, high adsorption speed, large number of well‐distributed micropores and large surface area (1000~2000 m 2 g −1 ) . Recently, ACFs have been of interest for application in low‐temperature SCR processes .…”

Section: Introductionmentioning

confidence: 99%

“…5 Activated carbon fibre (ACF), as one flexible material, constitutes an excellent catalyst support owing to its developed micropore structure, high adsorption speed, large number of well-distributed micropores and large surface area (1000~2000 m 2 g −1 ). 6,7 Recently, ACFs have been of interest for application in low-temperature SCR processes. 8,9 However, their application remains limited due to the poor stabilization between active components and the ACF support; the leakage of surfaceactive species inevitably occurrs in the catalytic process and then causes the deactivation of catalysts.…”

Section: Introductionmentioning

confidence: 99%

Manganese oxides supported on ACF_N by a one‐step redox method for the low‐temperature NOx reduction with NH₃: effect of acid addition

Tang

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND In this study, manganese dioxide (MnO2) was formed in situ on the surface of ACFN (nitric acid modified activated carbon fibres) by a one‐step redox method for the selective catalytic reduction (SCR) of nitric oxides (NOx) with ammonia (NH3) at low temperature. Meanwhile, the water and sulfur dioxide (H2O and SO2) deactivation mechanism were investigated. RESULTS Each acid, including hydrochloric, nitric and acetic (HCl, HNO3 and CH3COOH), released H+ in solution at different rates, which lead to distinct pH environments. As the driving force, it has an effect on the redox reaction, resulting in the different MnO2 amount and performance of the MnO2/ACFN catalysts. The MnO2/ACFN (CH3COOH) catalyst exhibited good NH3‐SCR activity, water resistance and sulfur resistance. CONCLUSION The MnO2/ACFN (CH3COOH) catalyst showed 3D growth and uniform distribution of MnO2 sheets on the surface of the support, which resulted in a larger specific surface area and better redox properties. The CH3COOH can gradually decompose H+ so that H+ is given priority to internal diffusion. The redox reaction preferentially took place in the interior, thereby promoting the formation of more MnO2, which is beneficial to the NH3‐SCR reaction. © 2019 Society of Chemical Industry

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Investigation of Low-Temperature Selective Catalytic Reduction of NOx with Ammonia over Mn-Modified Fe2O3/AC Catalysts

Abstract: A series of iron-based catalysts supported on activated carbon (AC) and manganese-modified ) and Mn 4+ /Mn 3+ , and improved the surface area and pore volume.

Cited by 19 publications

References 16 publications

Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism

Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism

De-NOx Performance and Mechanism of Mn-Based Low-Temperature SCR Catalysts Supported on Foamed Metal Nickel

Manganese oxides supported on ACF_N by a one‐step redox method for the low‐temperature NOx reduction with NH₃: effect of acid addition

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Investigation of Low-Temperature Selective Catalytic Reduction of NOx with Ammonia over Mn-Modified Fe2O3/AC Catalysts

Abstract: A series of iron-based catalysts supported on activated carbon (AC) and manganese-modified ) and Mn 4+ /Mn 3+ , and improved the surface area and pore volume.

Cited by 19 publications

References 16 publications

Effect of Mn addition on the low‐temperature NH3‐selective catalytic reduction of NOx over Fe2O3/activated coke catalysts: Experiment and mechanism

Effect of Mn addition on the low‐temperature NH3‐selective catalytic reduction of NOx over Fe2O3/activated coke catalysts: Experiment and mechanism

De-NOx Performance and Mechanism of Mn-Based Low-Temperature SCR Catalysts Supported on Foamed Metal Nickel

Manganese oxides supported on ACFN by a one‐step redox method for the low‐temperature NOx reduction with NH3: effect of acid addition

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Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism

Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism

Manganese oxides supported on ACF_N by a one‐step redox method for the low‐temperature NOx reduction with NH₃: effect of acid addition