Modulate the superficial structure of La2Ce2O7 catalyst with anchoring CuO  species for the selective catalytic oxidation of NH3

Kong, Xiangchen; Li, Zhenguo; Shao, Yuankai; Ren, Xiangzhong; Li, Kaixiang; Wu, Hanming; Lv, Congjie; Lv, Cheng; Zhu, Shengli

doi:10.1016/j.jmst.2021.09.044

Cited by 14 publications

(9 citation statements)

References 43 publications

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“…The outstanding features of pyrochlore, like good thermal stability, oxygen mobility, inherent oxygen vacancy, and good ionic transport, make this structure suitable for use in several areas, such as the manufacture of fuel cells, [29][30][31][32] in the production of hydrogen, 33 as gas sensors, 34,35 as a thermal barrier coating, 36,37 and for photocatalysis. 38 Recently, pyrochlore structures have been studied for soot oxidation, 39 ammonia oxidation, 40 methane dry reforming, 41 electrocatalysis, 42,43 and photocatalysis. 44 The stable crystalline phase for pyrochlore-type structures has already been unveiled by previous literature [45][46][47] and depends on the ratio between the ionic radius of the atoms located on sites A and B.…”

Section: Introductionmentioning

confidence: 99%

The catalytic activity of the Pr₂Zr₂₋_xFe_xO_7±_δ system for the CO oxidation reaction

et al. 2022

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One of the alternatives to decrease the concentration of CO is its oxidation reaction to CO 2 , which can be made more efficient using catalysts. In this work, it is shown that pyrochlore structures are a promising candidate to act as heterogeneous catalysts due to their chemical and physical properties. For use as a catalyst in this reaction, the Pr 2 Zr 2−x Fe x O 7±δ (x = 0, 0.05, 0.10, and 0.15) system was synthesized by the solvothermal method, firing the powder obtained at temperatures of 1200 and 1400 • C. The diffraction patterns confirmed the pyrochlore structure as the single phase in all the nominal compositions. The Brunauer-Emmett-Teller method and dynamic light-scattering analysis showed an increase in the particle size and a decrease in the specific surface area when increasing the iron concentration and increasing the calcination temperature. The compositions that presented the best catalytic activity were the samples with the highest iron concentration. Moreover, these samples were able to convert all the CO oxidation reactions in a narrower temperature range than a conventional CeO 2 sample. The presence of vacancies and the redox behavior of the elements present are the key factors for the catalysis of this system in the CO oxidation reaction.

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Section: Introductionmentioning

confidence: 99%

The catalytic activity of the Pr₂Zr₂₋_xFe_xO_7±_δ system for the CO oxidation reaction

et al. 2022

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“…Many studies have shown that HNO species are formed by the reaction of NH with atomic oxygen 62,63 and NH species are formed by the dehydrogenation of NH 3 by surface reactive oxygen to form NH 2 , after which NH 2 is dehydrogenated by surface reactive oxygen again. 62,64 The characteristic peaks of NH 3 , NH 2 , and HNO can be observed in our FTIR results, while the characteristic peaks of NH species are not observed, which is because NH species are not easily observed. 15,65 From the FTIR results, it is clear that the adsorbed NH 3 is dehydrogenated by surface reactive oxygen to form NH 2 and NH, NH reacts with atomic oxygen to form HNO, and HNO is oxidized by lattice oxygen to NO and adsorbed on the sites in the nitrate state.…”

Section: Mechanism Study Of Nh 3 -Sco Over the Cesno Xmentioning

confidence: 66%

Synergistic Effect over CeSnO_x Catalyst for the Selective Catalytic Oxidation of NH₃

Zhou

Zhang

Liu

et al. 2022

ACS Appl. Energy Mater.

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The N 2 selectivity of selective catalytic oxidation of NH 3 (NH 3 -SCO) at high temperatures is a great challenge. CeSnO x catalysts were synthesized by the coprecipitation method and systematically investigated. CeSnO x catalysts exhibited excellent N 2 selectivity at high temperatures compared to CeO 2 . The possible SCO reaction mechanism and synergistic effect over CeSnO x catalysts for NH 3 -SCO performance were investigated. X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption of ammonia (NH 3 -TPD) characterization manifested that the concentrations of O ads , Ce 3+ , and acid sites were increased. It is speculated that the reaction mechanism followed the internal-SCR (i-SCR) mechanism through in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments. Combined with density functional theory (DFT) calculations, it was verified that after doping Sn, the oxygen vacancy of CeSnO x catalysts possessed reduced formation energy, resulting from the shifting of electron density to Sn, redistribution of charge, and the smaller conduction band of O 2p, which also could be much easier to adsorb and stabilize oxygen as active sites. In addition, Sn doping succeeded in inhibiting the competitive adsorption of OH and NH 3 on the Ce site because Sn could preferentially adsorb OH and then adsorb and activate NH 3 . This work reveals the synergistic effect over CeSnO x catalysts for NH 3 -SCO performance, which is conducive to the rational design of cheap SCO catalysts replacing noble-metal-based catalysts.

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“…Depending on the applied clusters, H2O, O2 or -HNO were released, while the release of N2 was observed in the multiple-collision reactions of Cu5O3 + and Cu7O4 + clusters. Nevertheless, it is recognized that supported copper species (e.g., Cu/Al2O3 [61,62], CuO/carbon nanotubes [63]) or the combination of CuO and other transition or rare earth metal oxides, e.g., Fe2O3, CeO2, La2O3, CuCr2O4 and CuCrO2 or La2Ce2O7 (nonporous pyrochlore structure-A2B2O7) (e.g., [61,62,[64][65][66][67]) result in catalysts with enhanced activity and N2 selectivity in NH3-SCO. E.g., Gang et al [61,62] and afterward other authors [68][69][70][71] have proved the high ) (e.g., [61,62,[64][65][66][67]) result in catalysts with enhanced activity and N 2 selectivity in NH 3 -SCO.…”

Section: Other Metal Oxidesmentioning

confidence: 99%

“…Nevertheless, it is recognized that supported copper species (e.g., Cu/Al2O3 [61,62], CuO/carbon nanotubes [63]) or the combination of CuO and other transition or rare earth metal oxides, e.g., Fe2O3, CeO2, La2O3, CuCr2O4 and CuCrO2 or La2Ce2O7 (nonporous pyrochlore structure-A2B2O7) (e.g., [61,62,[64][65][66][67]) result in catalysts with enhanced activity and N2 selectivity in NH3-SCO. E.g., Gang et al [61,62] and afterward other authors [68][69][70][71] have proved the high ) (e.g., [61,62,[64][65][66][67]) result in catalysts with enhanced activity and N 2 selectivity in NH 3 -SCO. E.g., Gang et al [61,62] and afterward other authors [68][69][70][71] have proved the high catalytic activity of copper species deposited on γ-Al 2 O 3 .…”

Section: Other Metal Oxidesmentioning

confidence: 99%

A Comparative Mini-Review on Transition Metal Oxides Applied for the Selective Catalytic Ammonia Oxidation (NH3-SCO)

Jabłońska

Robles

2022

Materials

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The selective catalytic oxidation of NH3 (NH3-SCO) into N2 and H2O is an efficient technology for NH3 abatement in diesel vehicles. However, the catalysts dedicated to NH3-SCO are still under development. One of the groups of such catalysts constituted transition metal-based catalysts, including hydrotalcite-derived mixed metal oxides. This class of materials is characterized by tailored composition, homogenously dispersed mixed metal oxides, exhibiting high specific surface area and thermal stability. Thus, firstly, we give a short introduction to the structure and composition of hydrotalcite-like materials and their applications in NH3-SCO. Secondly, an overview of other transition metal-based catalysts reported in the literature is given, following a comparison of both groups. The challenges in NH3-SCO applications are provided, while the reaction mechanisms are discussed for particular systems.

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Modulate the superficial structure of La2Ce2O7 catalyst with anchoring CuO species for the selective catalytic oxidation of NH3

Cited by 14 publications

References 43 publications

The catalytic activity of the Pr₂Zr₂₋_xFe_xO_7±_δ system for the CO oxidation reaction

The catalytic activity of the Pr₂Zr₂₋_xFe_xO_7±_δ system for the CO oxidation reaction

Synergistic Effect over CeSnO_x Catalyst for the Selective Catalytic Oxidation of NH₃

A Comparative Mini-Review on Transition Metal Oxides Applied for the Selective Catalytic Ammonia Oxidation (NH3-SCO)

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Modulate the superficial structure of La2Ce2O7 catalyst with anchoring CuO species for the selective catalytic oxidation of NH3

Cited by 14 publications

References 43 publications

The catalytic activity of the Pr2Zr2−xFexO7±δ system for the CO oxidation reaction

The catalytic activity of the Pr2Zr2−xFexO7±δ system for the CO oxidation reaction

Synergistic Effect over CeSnOx Catalyst for the Selective Catalytic Oxidation of NH3

A Comparative Mini-Review on Transition Metal Oxides Applied for the Selective Catalytic Ammonia Oxidation (NH3-SCO)

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The catalytic activity of the Pr₂Zr₂₋_xFe_xO_7±_δ system for the CO oxidation reaction

The catalytic activity of the Pr₂Zr₂₋_xFe_xO_7±_δ system for the CO oxidation reaction

Synergistic Effect over CeSnO_x Catalyst for the Selective Catalytic Oxidation of NH₃