Mechanism by which three-dimensional ordered mesoporous CeO2 promotes the activity of VOx-MnOx/CeO2 catalysts for NOx abatement: Atomic-scale insight into the catalytic cycle

Wu, Xiaomin; Chen, Ziyi; Yu, Xiaolong; Shen, Huazhen; Jing, Guohua

doi:10.1016/j.cej.2020.125629

Cited by 32 publications

(23 citation statements)

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“…Defect engineering at all levels can be employed with oxides through doping (0D defects), heterojunction formation (1D and 2D defects), and the introduction of multiple vacancies in the form of divacancies and clusters and mesoporosity (3D defects). [13][14][15][16][17][18] These strategies target the enhancement of the semiconducting properties through defect generation, band alignment through heterojunction establishment, and increase in active site distribution density through the introduction of new interfacial areas. While point defects are a typical result of doping, a second important potential effect is charge compensation by redox, which is facilitated by the variable valences of transition and rare earth metals.…”

Section: Introductionmentioning

confidence: 99%

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions

Zheng

Mofarah

Cazorla

et al. 2021

Adv Funct Materials

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Critical catalysis studies often lack elucidation of the mechanistic role of defect equilibria in solid solubility and charge compensation. This approach is applied to interpret the physicochemical properties and catalytic performance of a free-standing 2D-3D CeO 2−x scaffold, which is comprised of holey 2D nanosheets, and its heterojunctions with MoO 3−x and RuO 2 . The band gap alignment and structural defects are engineered using density functional theory (DFT) simulations and atomic characterization. Further, the heterojunctions are used in hydrogen evolution reaction (HER) and catalytic ozonation applications, and the impacts of the metal oxide heteroatoms are analyzed. A key outcome is that the principal regulator of the ozonation performance is not oxygen vacancies but the concentration of Ce 3+ and Ce vacancies. Cation vacancy defects are measured to be as high as 8.1 at% for Ru-CeO 2−x . The homogeneous distribution of chemisorbed, Mo-oxide, heterojunction nanoparticles on the CeO 2−x holey nanosheets facilitates intervalence charge transfer, resulting in the dominant effect and resultant ≈50% decrease in overpotential for HER. The heterojunctions are tested for aqueous-catalytic ozonation of salicylic acid, revealing excellent catalytic performance from Mo doping despite the adverse impact of Ce vacancies. The present study highlights the use of defect engineering to leverage experimental and DFT results for band alignment.

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Section: Introductionmentioning

confidence: 99%

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions

Zheng

Mofarah

Cazorla

et al. 2021

Adv Funct Materials

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“…In general, the SCR activity and SO 2 resistance over V 2 O 5 −MnO 2 / 3D-CeO 2 were superior to those over V 2 O 5 −MnO 2 /CeO 2 at 250 °C. 17 Herein, the differences in SO 2 + H 2 O deactivation observed for the V 2 O 5 −MnO 2 /CeO 2 and V 2 O 5 −MnO 2 /3D-CeO 2 catalysts should be further discussed in the next section, which was crucial to determining the low-temperature SCR activity and SO 2 tolerance.…”

Section: Methodsmentioning

confidence: 97%

“…The 5 wt % V 2 O 5 and 5 wt % MnO 2 loaded on the 3D-CeO 2 and conventional CeO 2 support were prepared by the impregnation method. 17 Briefly, the various CeO 2 supports were impregnated with desired amounts of NH 4 VO 3 and Mn(NO 3 ) 2 •4H 2 O in an oxalic acid aqueous solution with a molar ratio of NH 4 VO 3 /H 2 C 2 O 4 = 1:2. The mixture was stirred for 3 h and evaporated at 80 °C by using a rotary evaporator.…”

Section: Methodsmentioning

confidence: 99%

“…It might be due to the mesoporous V 2 O 5 −MnO 2 /3D-CeO 2 catalyst possessing more acidity and stronger electronic interactions than V 2 O 5 −MnO 2 /CeO 2 illustrated in our previous work. 17 A longer time of SO 2 and H 2 O exposure was further investigated. As shown in Figure 1b, the SCR activity of the V 2 O 5 −MnO 2 /3D-CeO 2 catalyst could maintain ∼50% of NO conversion in the presence of both SO 2 and H 2 O in 20 h. Because of a dynamic balance between the generation and decomposition of ABS over the V 2 O 5 −MnO 2 /3D-CeO 2 catalyst, a longer time of SCR activity and SO 2 resistance was presented than that over the V 2 O 5 −MnO 2 /CeO 2 catalyst.…”

Section: Methodsmentioning

confidence: 99%

“…The mesoporous V 2 O 5 −MnO 2 / 3D-CeO 2 material was successful synthesized and confirmed by high-resolution transmission electron microscopy, XRD, and porosimetry in our previous report. 17 In this study, various characterizations, XRD, Raman, FT-IR, TG−DTG, and so forth, were performed to further investigate the reasons how the carrier effect of 3D mesoporous CeO 2 on the V 2 O 5 −MnO 2 /3D-CeO 2 catalyst can promote SO 2 resistance during the lowtemperature SCR process.…”

Section: Methodsmentioning

confidence: 99%

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Enhancement of SO₂ Resistance on Submonolayer V₂O₅–MnO₂/CeO₂ Catalyst by Three-Dimensional Ordered Mesoporous CeO₂ in Low-Temperature NH₃–SCR

Peng

Wang

et al. 2022

Energy Fuels

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Developing low-temperature (<300 °C) SO2-tolerant catalysts for NO x reduction is a challenge. A catalyst architecture of three-dimensional (3D) ordered mesoporous CeO2 supported by submonolayer V2O5 and MnO2 (V2O5–MnO2/3D-CeO2) was successfully prepared to promote the SO2 resistance in low-temperature selective catalytic reduction (SCR). The 3D ordered mesoporous channels were retained even after the exposure of the catalyst to SO2 and H2O. The presence of a highly 3D ordered mesoporous structure of V2O5–MnO2/3D-CeO2 can lead to high vapor pressure, which was beneficial for ammonium bisulfate vaporization and decomposition, eventually protecting the active vanadia sites. The stable active crystalline V2O5 species and the formative cerium sulfate promoters were crucial for determining the low-temperature SCR activity and SO2 tolerance in the presence of SO2 and H2O. Therefore, our V2O5–MnO2/3D-CeO2 catalyst delivered a large temperature range of 250–320 °C with NO conversion above 95%. The 3D ordered mesoporous channels of the V2O5–MnO2/3D-CeO2 catalyst provided an effective way to improve the SO2 resistance at 250 °C.

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Novel 2D Layered Manganese Silicate Nanosheets with Excellent Performance for Selective Catalytic Reduction of NO with Ammonia

Wan

Sun

et al. 2022

ChemCatChem

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Two‐dimensional (2D) catalysts are highly attractive for their great potential in environment remediation and energy conversion. In this work, a novel layered manganese silicate (MnSiO3) catalyst was synthesized by hydrothermal method using silica in vermiculite, a layered silicate clay mineral, as the lattice‐matching matrix and silicon source. The epitaxial growth of MnSiO3 is confined in the 2D directions, resulting in the morphology of vermiculite crystal thin nanosheets. The physichemical characterization results showed that MnSiO3 possessed higher Mn4+ content, acidic sites and reducing substances than that of MnOx/SiO2. The MnSiO3 therefore exhibited 100 % NO conversion rate with 85 % N2 selectivity at 150 °C in the NH3−SCR process. In situ DRIFTS studies show that MnSiO3 has strong NO adsorption capacity and NH3 activation capacity, which is beneficial to the improvement of NH3−SCR activity.

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Mechanism by which three-dimensional ordered mesoporous CeO2 promotes the activity of VOx-MnOx/CeO2 catalysts for NOx abatement: Atomic-scale insight into the catalytic cycle

Cited by 32 publications

References 49 publications

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions

Enhancement of SO₂ Resistance on Submonolayer V₂O₅–MnO₂/CeO₂ Catalyst by Three-Dimensional Ordered Mesoporous CeO₂ in Low-Temperature NH₃–SCR

Novel 2D Layered Manganese Silicate Nanosheets with Excellent Performance for Selective Catalytic Reduction of NO with Ammonia

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Mechanism by which three-dimensional ordered mesoporous CeO2 promotes the activity of VOx-MnOx/CeO2 catalysts for NOx abatement: Atomic-scale insight into the catalytic cycle

Cited by 32 publications

References 49 publications

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO2−x‐Based Heterojunctions

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO2−x‐Based Heterojunctions

Enhancement of SO2 Resistance on Submonolayer V2O5–MnO2/CeO2 Catalyst by Three-Dimensional Ordered Mesoporous CeO2 in Low-Temperature NH3–SCR

Novel 2D Layered Manganese Silicate Nanosheets with Excellent Performance for Selective Catalytic Reduction of NO with Ammonia

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Product

Resources

About

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions

Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO₂₋_x‐Based Heterojunctions

Enhancement of SO₂ Resistance on Submonolayer V₂O₅–MnO₂/CeO₂ Catalyst by Three-Dimensional Ordered Mesoporous CeO₂ in Low-Temperature NH₃–SCR