SO2-Tolerant Catalytic Reduction of NOx via Tailoring Electron Transfer between Surface Iron Sulfate and Subsurface Ceria

Qi, Xinran; Han, Lupeng; Deng, Jiang; Lan, Tianwei; Wang, Fuli; Shi, Liyi; Zhang, Dengsong

doi:10.1021/acs.est.2c00944

Cited by 56 publications

(23 citation statements)

References 55 publications

(73 reference statements)

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“…In recent years, iron oxide has been proposed as a promising material for deNO x applications, due to its superior performance in medium- and high-temperature ranges (>300 °C) and good SO 2 resistance in the NH 3 -SCR reaction, which should originate from its good redox ability and its unique surface properties against SO 2 poisoning. − However, its low-temperature activity still cannot meet the requirements for the NH 3 -SCR reaction, and therefore, many efforts have been devoted to improve the low-temperature reactivity of Fe-based catalysts by introducing a dopant into the iron oxide matrix or controlling the exposed surface facet of iron oxide in recent years. − In our previous work, we have successfully synthesized Fe–Sm catalysts, which exhibited excellent NO conversion from 175 to 325 °C and could maintain >83% NO conversion for 168 h in the presence of H 2 O and SO 2 . These studies clearly suggest the promotion influence of the dopant on the catalytic performances of iron oxide catalysts.…”

Section: Introductionmentioning

confidence: 99%

Single-Atom Ce-Modified α-Fe₂O₃ for Selective Catalytic Reduction of NO with NH₃

Chen

Yang

Liu

et al. 2022

Environ. Sci. Technol.

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A single-atom Ce-modified α-Fe2O3 catalyst (Fe0.93Ce0.07O x catalyst with 7% atomic percentage of Ce) was synthesized by a citric acid-assisted sol–gel method, which exhibited excellent performance for selective catalytic reduction of NO x with NH3 (NH3-SCR) over a wide operating temperature window. Remarkably, it maintained ∼93% NO conversion efficiency for 168 h in the presence of 200 ppm SO2 and 5 vol % H2O at 250 °C. The structural characterizations suggested that the introduction of Ce leads to the generation of local Fe–O–Ce sites in the FeO x matrix. Furthermore, it is critical to maintain the atomic dispersion of the Ce species to maximize the amounts of Fe–O–Ce sites in the Ce-doped FeO x catalyst. The formation of CeO2 nanoparticles due to a high doping amount of Ce species leads to a decline in catalytic performance, indicating a size-dependent catalytic behavior. Density functional theory (DFT) calculation results indicate that the formation of oxygen vacancies in the Fe–O–Ce sites is more favorable than that in the Fe–O–Fe sites in the Ce-free α-Fe2O3 catalyst. The Fe–O–Ce sites can promote the oxidation of NO to NO2 on the Fe0.93Ce0.07O x catalyst and further facilitate the reduction of NO x by NH3. In addition, the decomposition of NH4HSO4 can occur at lower temperatures on the Fe0.93Ce0.07O x catalyst containing atomically dispersed Ce species than on the α-Fe2O3 reference catalyst, resulting in the good SO2/H2O resistance ability in the NH3-SCR reaction.

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Section: Introductionmentioning

confidence: 99%

Single-Atom Ce-Modified α-Fe₂O₃ for Selective Catalytic Reduction of NO with NH₃

Chen

Yang

Liu

et al. 2022

Environ. Sci. Technol.

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“…Previous researches have affirmed that O species played a vital role in NH3-SCR reaction 8,27 . XPS was used to detect O species of each sample.…”

Section: Structural and Chemical Propertiesmentioning

confidence: 96%

Effect of Potassium on the Performance of a CuSO4/TiO2 Catalyst Used in the Selective Catalytic Reduction of NOx by NH3

Yu¹,

Geng²,

Wei³

et al. 2022

Acta Physico Chimica Sinica

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Owing to its renewability, abundance, and low environmental impact, biomass is considered to be a viable eco-friendly fuel. Various biofuelfired power plants have been built worldwide to reduce carbon emissions. Potassium (K) is a typical impurity in the flue gas from biofuel combustion that can deactivate the catalyst used in the selective catalytic reduction of NOx by ammonia (NH3-SCR). CuSO4/TiO2, with excellent sulfur dioxide tolerance, is thought to be a promising vanadium-free catalyst for NH3-SCR; however, the influence of K on the CuSO4/TiO2 catalyst is still unknown. Therefore, in this study, the effect of K on the NH3-SCR performance of CuSO4/TiO2 were investigated and compared with the effect on the performance of the commercial V2O5-WO3/TiO2 (VWTi) catalyst. K-poisoned catalysts were prepared via wet impregnation using potassium acetate as the K source. Nitrogen (N2) adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), NH3-temperature programmed desorption (NH3-TPD), H2temperature programmed reduction (H2-TPR), and in situ diffuse reflectance infrared Fourier-transform spectroscopy (in situ DRIFTS) were used to characterize the prepared catalysts. The NOx conversion over CuSO4/TiO2 with 1.0% (w) K was 92.1% (at 350 °C), which was higher than the conversion (75.1%) achieved over the commercial VWTi catalyst with the same K content. The XRD, XPS, and H2-TPR results suggested that K reacted with the CuSO4 in the CuSO4/TiO2 catalyst to form CuO and K2SO4. The presence of CuO enhanced the oxidation of NH3 to N2O, NO, and NO2 during NH3-SCR, thereby decreasing the NOx conversion and N2 selectivity over CuSO4/TiO2. Moreover, based on the results from NH3-TPD and in situ DRIFTS of NH3 adsorption, it can be concluded that the Brønsted acid sites (S-OH) were poisoned by K, which restrained the adsorption of NH3 on CuSO4/TiO2. Additionally, the high K content altered the pore structure of the catalyst, leading to a decrease in the specific surface area. However, according to the in situ DRIFTS results, NH3-SCR over K-poisoned CuSO4/TiO2 still followed the Eley-Rideal mechanism: First, NH3 was adsorbed on the Lewis and Brønsted acid sites of the catalyst, and then gaseous NO and O2 reacted with the adsorbed NH3/NH4+ on the acid sites, resulting in the formation of N2 and H2O. Notably, the abundance of acid sites and surface-adsorbed oxygen species on CuSO4/TiO2 could be the main reason for its higher resistance to K-poisoning. In conclusion, our current findings suggested that CuSO4/TiO2 might be a suitable NH3-SCR catalyst for use in the flue gas streams from biofuel-fired power plants.

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“…Fortunately, many reports focusing on the preparation of anti-poisoning catalysts can provide constructive information for the perspectives of CeO 2 -based catalysts in CO 2 methanation. 60,[185][186][187][188][189][190][191] Jeong et al 192 proposed that the hydrothermal treatment of Pd/CeO 2 catalyst promoted the redispersion of Pd species and the formation of surface OH groups. This further increased the CO oxidation activity over Pd/CeO 2 and the resistance of the sample to surface poisoning compounds (Fig.…”

Section: Tolerance Of Ceo 2 -Based Catalystsmentioning

confidence: 99%

Progress in reaction mechanisms and catalyst development of ceria-based catalysts for low-temperature CO₂methanation

Xie

Wen

et al. 2023

Green Chem.

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SO₂-Tolerant Catalytic Reduction of NO_x via Tailoring Electron Transfer between Surface Iron Sulfate and Subsurface Ceria

Cited by 56 publications

References 55 publications

Single-Atom Ce-Modified α-Fe₂O₃ for Selective Catalytic Reduction of NO with NH₃

Single-Atom Ce-Modified α-Fe₂O₃ for Selective Catalytic Reduction of NO with NH₃

Effect of Potassium on the Performance of a CuSO<sub>4</sub>/TiO<sub>2</sub> Catalyst Used in the Selective Catalytic Reduction of NO<sub><i>x</i></sub> by NH<sub>3</sub>

Progress in reaction mechanisms and catalyst development of ceria-based catalysts for low-temperature CO₂methanation

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SO2-Tolerant Catalytic Reduction of NOx via Tailoring Electron Transfer between Surface Iron Sulfate and Subsurface Ceria

Cited by 56 publications

References 55 publications

Single-Atom Ce-Modified α-Fe2O3 for Selective Catalytic Reduction of NO with NH3

Single-Atom Ce-Modified α-Fe2O3 for Selective Catalytic Reduction of NO with NH3

Effect of Potassium on the Performance of a CuSO<sub>4</sub>/TiO<sub>2</sub> Catalyst Used in the Selective Catalytic Reduction of NO<sub><i>x</i></sub> by NH<sub>3</sub>

Progress in reaction mechanisms and catalyst development of ceria-based catalysts for low-temperature CO2methanation

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Resources

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SO₂-Tolerant Catalytic Reduction of NO_x via Tailoring Electron Transfer between Surface Iron Sulfate and Subsurface Ceria

Single-Atom Ce-Modified α-Fe₂O₃ for Selective Catalytic Reduction of NO with NH₃

Single-Atom Ce-Modified α-Fe₂O₃ for Selective Catalytic Reduction of NO with NH₃

Progress in reaction mechanisms and catalyst development of ceria-based catalysts for low-temperature CO₂methanation