Atomically dispersed Mn atoms coordinated with N and O within an N-doped porous carbon framework for boosted oxygen reduction catalysis

Huo, Juanjuan; Cao, Xiaomei; Tian, Yaping; Li, Lü; Qu, Junpeng; Xie, Yuhan; Xie, Xinming; Zhao, Yufei; Liu, Hao

doi:10.1039/d2nr06096e

“…[33] The chemical states of the as-prepared samples were further studied by X-ray photoelectron spectroscopic (XPS). The high-resolution XPS spectra of N 1s for Fe1/NSOC and Fe1/NC (Figure S7a) exhibit similar peak positions and intensities, suggesting the existence of pyridinic N/FeÀ N, pyrrolic N and graphitic N. [26,34] The presence of FeÀ N indicates the Fe single atoms coordinated with the surrounding N atoms in both catalysts. The high-resolution O 1s XPS spectra in Figure 2a show the peaks for three oxygen Angewandte Chemie components, including ketonic oxygen (C=O, O1, � 531.2 eV), oxygen atoms in epoxy (CÀ OÀ C) or hydroxyl groups and carbonyl oxygen in ester groups (O2, � 532.0 eV), and the epoxy oxygen in ester groups (O3, � 533.2 eV).…”

Section: Resultsmentioning

confidence: 91%

Epoxy‐rich Fe Single Atom Sites Boost Oxygen Reduction Electrocatalysis

Zhao

¹

,

Shen

²

,

Huo

³

et al. 2023

Self Cite

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Electrocatalysts for highly efficient oxygen reduction reaction (ORR) are crucial for energy conversion and storage devices. Single‐atom catalysts with maximized metal utilization and altered electronic structure are the most promising alternatives to replace current benchmark precious metals. However, the atomic level understanding of the functional role for each species at the anchoring sites is still unclear and poorly elucidated. Herein, we report Fe single atom catalysts with the sulfur and oxygen functional groups near the atomically dispersed metal centers (Fe1/NSOC) for highly efficient ORR. The Fe1/NSOC delivers a half‐wave potential of 0.92 V vs. RHE, which is much better than those of commercial Pt/C (0.88 V), Fe single atoms on N‐doped carbon (Fe1/NC, 0.89 V) and most reported nonprecious metal catalysts. The spectroscopic measurements reveal that the presence of sulfur group induces the formation of epoxy groups near the FeN4S2 centers, which not only modulate the electronic structure of Fe single atoms but also participate the catalytic process to improve the kinetics. The density functional theory calculations demonstrate the existence of sulfur and epoxy group engineer the charges of Fe reactive center and facilitate the reductive release of OH* (rate‐limiting step), thus boosting the overall oxygen reduction efficiency.

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“…[33] The chemical states of the as-prepared samples were further studied by X-ray photoelectron spectroscopic (XPS). The high-resolution XPS spectra of N 1s for Fe1/NSOC and Fe1/NC (Figure S7a) exhibit similar peak positions and intensities, suggesting the existence of pyridinic N/FeÀ N, pyrrolic N and graphitic N. [26,34] The presence of FeÀ N indicates the Fe single atoms coordinated with the surrounding N atoms in both catalysts. The high-resolution O 1s XPS spectra in Figure 2a show the peaks for three oxygen components, including ketonic oxygen (C=O, O1, � 531.2 eV), oxygen atoms in epoxy (CÀ OÀ C) or hydroxyl groups and carbonyl oxygen in ester groups (O2, � 532.0 eV), and the epoxy oxygen in ester groups (O3, � 533.2 eV).…”

Section: Resultsmentioning

confidence: 91%

“…[24,25] Recently, it has been also demonstrated that the oxygen groups, such as the epoxy group, near the atomically dispersed metal centers play a significant role in determining the selectivity and catalytic activity during ORR process. [26][27][28] Except for the modification effect, these nonmetal atoms (e.g., C and N atoms) in SACs can also participate in the electrocatalysis process as additional active sites, which offers a promising strategy to further boost the catalytic activity. [29] However, in-depth understanding the roles of these heteroatoms in SACs is still missing, and a systematic investigation is of great significance to investigate the catalytic mechanism at the atomic level, which will guide the design of efficient catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…The above studies suggested the heteroatoms directly coordinated or beyond the first coordinated shell can efficiently engineer the properties of the metal centers for superior catalytic activity [24,25] . Recently, it has been also demonstrated that the oxygen groups, such as the epoxy group, near the atomically dispersed metal centers play a significant role in determining the selectivity and catalytic activity during ORR process [26–28] . Except for the modification effect, these nonmetal atoms (e.g., C and N atoms) in SACs can also participate in the electrocatalysis process as additional active sites, which offers a promising strategy to further boost the catalytic activity [29] .…”

Section: Introductionmentioning

confidence: 99%

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Epoxy‐rich Fe Single Atom Sites Boost Oxygen Reduction Electrocatalysis

Zhao

¹

,

Shen

²

,

Huo

³

et al. 2023

Self Cite

View full text Add to dashboard Cite

Electrocatalysts for highly efficient oxygen reduction reaction (ORR) are crucial for energy conversion and storage devices. Single‐atom catalysts with maximized metal utilization and altered electronic structure are the most promising alternatives to replace current benchmark precious metals. However, the atomic level understanding of the functional role for each species at the anchoring sites is still unclear and poorly elucidated. Herein, we report Fe single atom catalysts with the sulfur and oxygen functional groups near the atomically dispersed metal centers (Fe1/NSOC) for highly efficient ORR. The Fe1/NSOC delivers a half‐wave potential of 0.92 V vs. RHE, which is much better than those of commercial Pt/C (0.88 V), Fe single atoms on N‐doped carbon (Fe1/NC, 0.89 V) and most reported nonprecious metal catalysts. The spectroscopic measurements reveal that the presence of sulfur group induces the formation of epoxy groups near the FeN4S2 centers, which not only modulate the electronic structure of Fe single atoms but also participate the catalytic process to improve the kinetics. The density functional theory calculations demonstrate the existence of sulfur and epoxy group engineer the charges of Fe reactive center and facilitate the reductive release of OH* (rate‐limiting step), thus boosting the overall oxygen reduction efficiency.

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“…DFT calculations are a useful approach to investigate the thermodynamics of intermediates over electrocatalysts and have been applied to explore the reaction mechanism of the acidic OER. [140][141][142][143][144][145] However, the reaction mechanism of DFT may not be accurate because OER steps in different reaction mechanisms can exhibit sample η. Moreover, the surfaces of electrocatalysts usually undergo reconstruction during the OER in acid solutions, so real active materials should be the obtained species after structural evolution.…”

Section: Discussionmentioning

confidence: 99%

Designing and regulating catalysts for enhanced oxygen evolution in acid electrolytes

Yuan

¹

,

Zhao

²

,

Huang

³

et al. 2023

Carbon Neutralization

5

0

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The proton exchange membrane (PEM) water electrolyzer has been considered a versatile approach for practical H2 production. However, the oxygen evolution reaction (OER) in acid media with complicated proton‐coupled electron transfer steps possesses sluggish kinetics and high reaction barriers, severely hindering the development of PEM water electrolyzers. Consequently, high‐efficient Ru‐ and Ir‐based catalysts have always been essential to accelerate the OER rate and lower the reaction barrier in PEM water electrolyzer. Therefore, it is very necessary to construct low‐cost catalysts with excellent electrocatalytic performances to replace these noble metal‐based OER electrocatalysts. In this review paper, a detailed discussion towards fundamentally comprehending the reaction mechanisms of OER was conducted. Accordingly, we proposed the principles of designing advanced OER electrocatalysts with enhanced performances and lowered costs. After that, recent developments in designing various acidic OER electrocatalysts were summarized. Meanwhile, the available regulation strategies about noble metals, nonprecious metals, and metal‐free nanomaterials were presented, which are promising for tuning the electronic structures, boosting the electrocatalytic performances, and reducing the costs of electrocatalysts. We also provided the existing challenges and perspectives of various OER electrocatalysts, hoping to promote the development of PEM water electrolyzers.

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Atomically dispersed Mn atoms coordinated with N and O within an N-doped porous carbon framework for boosted oxygen reduction catalysis

Abstract: Developing efficient and robust catalysts to replace Pt group metals for oxygen reduction reaction (ORR) is conducive to achieve highly efficient energy conversion. Here, we develop a general ion exchange...

Cited by 37 publications

References 43 publications

Epoxy‐rich Fe Single Atom Sites Boost Oxygen Reduction Electrocatalysis

Epoxy‐rich Fe Single Atom Sites Boost Oxygen Reduction Electrocatalysis

Epoxy‐rich Fe Single Atom Sites Boost Oxygen Reduction Electrocatalysis

Designing and regulating catalysts for enhanced oxygen evolution in acid electrolytes

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