Axial coordination tuning Fe single-atom catalysts for boosting H2O2 activation

Fu, Haoyu; Wei, Jiaqi; Chen, Guoliang; Xu, Minkai; Liu, Jiyuan; Zhang, Jianghong; Li, Ké; Xu, Qianyu; Zou, Yunjie; Zhang, Wei‐xian; Chen, Xiao; Li, Shuzhou; Ling, Lan

doi:10.1016/j.apcatb.2022.122012

Cited by 43 publications

(22 citation statements)

References 52 publications

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“…The dominant peak assigned to the Fe–N(C) shell was observed only at ∼1.41 Å in R space, ascribed to the backscattering paths of Fe–N and Fe–C, while no signal was detected for the Fe–Fe shell (Figure d). , More importantly, with the increase of the pyrolysis temperature, the strength of Fe–N shells in R space slightly left shifts and decreases, indicating that the number of Fe-coordinated N atoms reduces and shorter Fe–C bonds are introduced, which pulls down the average bond lengths of the coordination bonds in the Fe center . Wavelet transform (WT) contour plots exhibit a single intensity maximum at about 4 Å –1 with no Fe–Fe signal in all Fe–N x C 4– x samples (Figure e) . According to the EXAFS best-fitting results (Figures f–h, S11 and S12, and Table S1), the average coordination numbers can be quantified directly.…”

Section: Resultsmentioning

confidence: 98%

“…41 Wavelet transform (WT) contour plots exhibit a single intensity maximum at about 4 Å −1 with no Fe−Fe signal in all Fe−N x C 4−x samples (Figure 3e). 42 S13a). The Raman spectra of the as-prepared Fe−N x C 4−x catalysts also display similar D band intensities corresponding to crystal defects (Figure S13b).…”

Section: Mechanistic Understanding Of the Catalyticmentioning

confidence: 99%

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Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification

Wu,

Huang,

Wang

et al. 2023

Environ. Sci. Technol.

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Precisely identifying the atomic structures in single-atom sites and establishing authentic structure–activity relationships for single-atom catalyst (SAC) coordination are significant challenges. Here, theoretical calculations first predicted the underlying catalytic activity of Fe–N x C4–x sites with diverse first-shell coordination environments. Substituting N with C to coordinate with the central Fe atom induces an inferior Fenton-like catalytic efficiency. Then, Fe-SACs carrying three configurations (Fe–N2C2, Fe–N3C1, and Fe–N4) fabricate facilely and demonstrate that optimized coordination environments of Fe–N x C4–x significantly promote the Fenton-like catalytic activity. Specifically, the reaction rate constant increases from 0.064 to 0.318 min–1 as the coordination number of Fe–N increases from 2 to 4, slightly influencing the nonradical reaction mechanism dominated by 1O2. In-depth theoretical calculations unveil that the modulated coordination environments of Fe-SACs from Fe–N2C2 to Fe–N4 optimize the d-band electronic structures and regulate the binding strength of peroxymonosulfate on Fe–N x C4–x sites, resulting in a reduced energy barrier and enhanced Fenton-like catalytic activity. The catalytic stability and the actual hospital sewage treatment capacity also showed strong coordination dependency. This strategy of local coordination engineering offers a vivid example of modulating SACs with well-regulated coordination environments, ultimately maximizing their catalytic efficiency.

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Section: Resultsmentioning

confidence: 98%

Section: Mechanistic Understanding Of the Catalyticmentioning

confidence: 99%

Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification

Wu,

Huang,

Wang

et al. 2023

Environ. Sci. Technol.

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“…The maximum phenol degradation rate in SACs reaches 0.158 min –1 when the synthesis conditions are Fe addition of 4 wt %, a calcination time of 3 h, a calcination heating rate of 0.6 °C/min, a calcination temperature of 680 °C, N addition of 18%, Fe addition of 4%, a pyrolysis heating rate of 0.7 °C/min, a pyrolysis time of 2 h, and a pyrolysis temperature of 240 °C, which substantially surpasses the highest k in the original data set. More importantly, such a high k value of an ML-guided SAC is higher than most other reported state-of-the-art Fe-based Fenton-like catalysts (Figure a and Table S3), − which verifies the effectiveness of the trained ML model.…”

Section: Resultsmentioning

confidence: 57%

“…Additionally, a gradual decrease of the pyridinic N content and an increase of graphitic N content from OSAC-I to OSAC-IV can be found in the N 1s spectrum. Note that the deconvoluted peaks at 399.6 eV corresponding to Fe–N x species for all SACs emerge compared with N-rGO (Figure c), which demonstrates the coordination environment of Fe sites is associated with N species. In case the local coordination structure of heterogeneously anchored single atoms is often considered a rigid ligand that is embedded on the catalyst surface, the catalytic activity of SACs is supposed to be controlled predominantly by modulating this coordination environment.…”

Section: Resultsmentioning

confidence: 99%

Machine-Learning-Assisted Optimization of a Single-Atom Coordination Environment for Accelerated Fenton Catalysis

Zhang

et al. 2023

ACS Nano

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Machine learning (ML) algorithms will be enablers in revolutionizing traditional methods of materials optimization. Here, we broaden the use of ML to assist the construction of Fenton-like single-atom catalysts (SACs) by developing a methodology including model building, training, and prediction. Our approach can efficiently extract synthesis parameters that exert a substantial influence on Fenton activity and accurately predict the phenol degradation rate k of SACs with a mean error of ±0.018 min −1 . The extended synthesis window with accelerated learning enables the realization that the heating temperatures during SAC synthesis significantly influence the Fe−N coordination number, which ultimately dictates their performance. Through ML-guided optimization, a highly efficient SAC dominated by Fe−N 5 sites with exceptional Fenton activity (k = 0.158 min −1 ) is identified. Our work provides an example for ML-assisted optimization of single-atom coordination environments and illuminates the feasibility of ML in accelerating the development of high-performance catalysts.

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“…In addition, Fu et al reported a novel SAC containing an axial ligand structure by obtaining isolated Fe–N sites. It can dramatically change the electronic states of Fe and lower the activation barrier of *OH formation by H 2 O 2 . The main products of H 2 O 2 activation include oxidative free radicals such as • OH, • OOH, and • O.…”

Section: Introductionmentioning

confidence: 99%

NO Oxidation Using H₂O₂ at a Single-Atom Iron Catalyst

et al. 2023

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Nitrogen oxide (NO) is a major worldwide environmental pollutant, which can be eliminated effectively by catalytic oxidation. However, conventional catalysts generally suffer from poor activity and low oxidation rates, limiting the development of gas pollutant removal. To overcome this issue, the high activity of a single-atom catalyst and the strong oxidizability of H2O2 are proposed for the catalytic oxidation of NO in this work. Herein, the 14 reaction pathways of NO oxidation using H2O2 were obtained through spin-polarized density functional theory calculation with van der Waals corrections and microkinetic modeling. Considering the possible H2O2 activation products of *OH, *OOH, and *O, we obtained the dominant reaction pathways for different oxidizing species: (i) Langmuir–Hinshelwood mechanism of *OH (mainly forming *HNO2), (ii) Eley–Rideal mechanism of *O (forming *NO2), and (iii) *OOH (forming *HNO3), with the energy barriers of 0.94, 1.42, and 0.14 eV, respectively. Among the three reaction patterns, NO oxidation using *OOH is the most favorable, with the highest reaction rate. *HNO3 is the most likely oxidation product of NO oxidation using H2O2. Meanwhile, it is notable that the *OH catalytic oxidation of NO has multiple reaction pathways and products, including HNO2, NO2, and HNO3. Compared to the use of conventional oxidants and catalysts, using H2O2 to oxidize NO at Fe–N4–C catalyst has lower reaction energy barriers and allows for the deep oxidation of NO. This study illustrates the reaction pathway of NO oxidation using H2O2 and demonstrates that it is theoretically feasible, which provides guidance for the subsequent preparation of the material.

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Axial coordination tuning Fe single-atom catalysts for boosting H2O2 activation

Cited by 43 publications

References 52 publications

Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification

Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification

Machine-Learning-Assisted Optimization of a Single-Atom Coordination Environment for Accelerated Fenton Catalysis

NO Oxidation Using H₂O₂ at a Single-Atom Iron Catalyst

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Axial coordination tuning Fe single-atom catalysts for boosting H2O2 activation

Cited by 43 publications

References 52 publications

Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification

Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification

Machine-Learning-Assisted Optimization of a Single-Atom Coordination Environment for Accelerated Fenton Catalysis

NO Oxidation Using H2O2 at a Single-Atom Iron Catalyst

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NO Oxidation Using H₂O₂ at a Single-Atom Iron Catalyst