Study of OER electrocatalysts performance of Fe/Mn doped pyrochlorestructure

Han, Tianru; Wu, Jingjing; Lu, Xianglong; Wang, Yingchao; Zhao, Huining; Tang, Xiaohong

doi:10.1016/j.jssc.2021.122457

Cited by 8 publications

(5 citation statements)

References 38 publications

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“…Additional file 1 : Figure S8 shows the geometric activity of YMRO-x, where YRO exhibits highest geometric current density among the series due to its highest Ru ratio. This result differs from a previous report, in which Y 2 Mn 0.1 Ru 1.9 O 7 outperformed YRO [ 41 ]. This apparent difference can be explained by the tradeoff between the Ru amount in the catalyst and the mass activity of Ru.…”

Section: Resultscontrasting

confidence: 99%

“…For example, we previously prepared pyrochlore Y 2 Ru 2 O 7 with a particle size of around 40 nm using polymer entrapment flash pyrolysis method, and showed an enhanced OER activity compared with those having larger sizes [ 31 ]. This strategy is complementary to those that affect the intrinsic reaction kinetics, such as oxidation state, conductivity, electronic structure, binding groups on the surface and fermi level, through metal substitution [ 35 – 37 , 40 , 41 ], to further improve the OER catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Regulating the electronic structures of mixed B-site pyrochlore to enhance the turnover frequency in water oxidation

et al. 2022

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This paper describes the development of mixed B-site pyrochlore Y2MnRuO7 electrocatalyst for oxygen evolution reaction (OER) in acidic media, a challenge for the development of low-temperature electrolyzer for green hydrogen production. Recently, several theories have been developed to understand the reaction mechanism for OER, though there is an uncertainty in most of the cases, due to the complex surface structures. Several key factors such as lattice oxygen, defect, electronic structure, oxidation state, hydroxyl group and conductivity were identified and shown to be important to the OER activity. The contribution of each factor to the performance however is often not well understood, limiting their impact in guiding the design of OER electrocatalysts. In this work, we showed mixed B-site pyrochlore Y2MnRuO7 catalyst exhibits 14 times higher turnover frequency (TOF) than RuO2 while maintaining a low overpotential of ~ 300 mV for the entire testing period of 24 h in acidic electrolyte. X-ray photoelectron spectroscopy (XPS) analysis reveals that this B-site mixed pyrochlore Y2MnRuO7 has a higher oxidation state of Ru than those of Y2Ru2O7, which could be crucial for improving OER performance as the broadened and lowered Ru 4d band resulted from the B-site substitution by Mn is beneficial to the OER kinetics.

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Section: Resultscontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Regulating the electronic structures of mixed B-site pyrochlore to enhance the turnover frequency in water oxidation

et al. 2022

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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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“…The existence of a similar zero crossing feature for the electrocatalysts indicates that both Y 2 Ru 2 O 7−δ and Y 2 (Y 0.2 Ru 0.8 ) 2 O 7−δ have a Ru 4+ oxidation state. Thus, the observed enhancement in OER activity can be attributed in part to the mixed valence of Ru (4 + /5 + ). ,,− …”

Section: Results and Discussionmentioning

confidence: 97%

Defect Engineering in Composition and Valence Band Center of Y₂(Y_xRu_1–x)₂O_7−δ Pyrochlore Electrocatalysts for Oxygen Evolution Reaction

Ghosh,

Zhang,

Frick

et al. 2024

J. Am. Chem. Soc.

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Oxygen evolution reaction (OER) takes place in various types of electrochemical devices that are pivotal for the conversion and storage of renewable energy. This paper describes a strategy in the design of solid-state structures of OER electrocatalysts through controlling the cation substitution on the active metal site and consequently valence band center position of site-mixed Y2(Y x Ru1–x )2O7−δ pyrochlore to achieve high catalytic activity. We found that partially replacing the B-site Ru4+ cation with A-site Y3+ in pyrochlore-structured Y2Ru2O7−δ modifies the oxidation state of B-site Ru from 4+ to 5+, as observed by electron paramagnetic resonance (EPR) spectroscopy but does not continuously increase the oxygen vacancy concentration in these oxygen substoichiometric compositions, as quantified by thermogravimetric analysis (TGA) decomposition studies. We found the increased Ru oxidation state leads to a downshift in valence band center. X-ray photoelectron spectroscopy (XPS) analysis was performed to quantitatively determine the optimal band center to be ∼1.27 eV below the Fermi energy level based on the analysis of the valence band edge of these Ru-based Y2(Y x Ru1–x )2O7−δ OER electrocatalysts. This work highlights that defect engineering can be a practical, effective approach to the optimization of oxidation state and electronic band center for high OER catalytic performance in a quantitative manner.

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Study of OER electrocatalysts performance of Fe/Mn doped pyrochlorestructure

Cited by 8 publications

References 38 publications

Regulating the electronic structures of mixed B-site pyrochlore to enhance the turnover frequency in water oxidation

Regulating the electronic structures of mixed B-site pyrochlore to enhance the turnover frequency in water oxidation

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

Defect Engineering in Composition and Valence Band Center of Y₂(Y_xRu_1–x)₂O_7−δ Pyrochlore Electrocatalysts for Oxygen Evolution Reaction

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Study of OER electrocatalysts performance of Fe/Mn doped pyrochlorestructure

Cited by 8 publications

References 38 publications

Regulating the electronic structures of mixed B-site pyrochlore to enhance the turnover frequency in water oxidation

Regulating the electronic structures of mixed B-site pyrochlore to enhance the turnover frequency in water oxidation

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

Defect Engineering in Composition and Valence Band Center of Y2(YxRu1–x)2O7−δ Pyrochlore Electrocatalysts for Oxygen Evolution Reaction

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

Defect Engineering in Composition and Valence Band Center of Y₂(Y_xRu_1–x)₂O_7−δ Pyrochlore Electrocatalysts for Oxygen Evolution Reaction