Axial ligand effect on the stability of Fe–N–C electrocatalysts for acidic oxygen reduction reaction

Wang, Feiteng; Zhou, Yipeng; Lin, Sen; Yang, Lijun; Hu, Zheng; Xie, Daiqian

doi:10.1016/j.nanoen.2020.105128

Cited by 66 publications

(75 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… a) Schematic depicting the reaction from *OOH to *H 2 O 2 or H 2 O. Reproduced with permission. [ 73 ] Copyright 2020, Elsevier. b) Hydrogen peroxide production and electron transfer number of different catalysts.…”

Section: Improvement Strategies For Stabilitymentioning

confidence: 99%

See 1 more Smart Citation

Stabilizing Fe–N–C Catalysts as Model for Oxygen Reduction Reaction

et al. 2021

View full text Add to dashboard Cite

The highly efficient energy conversion of the polymer-electrolyte-membrane fuel cell (PEMFC) is extremely limited by the sluggish oxygen reduction reaction (ORR) kinetics and poor electrochemical stability of catalysts. Hitherto, to replace costly Pt-based catalysts, non-noble-metal ORR catalysts are developed, among which transition metal-heteroatoms-carbon (TM-H-C) materials present great potential for industrial applications due to their outstanding catalytic activity and low expense. However, their poor stability during testing in a two-electrode system and their high complexity have become a big barrier for commercial applications. Thus, herein, to simplify the research, the typical Fe-N-C material with the relatively simple constitution and structure, is selected as a model catalyst for TM-H-C to explore and improve the stability of such a kind of catalysts. Then, different types of active sites (centers) and coordination in Fe-N-C are systematically summarized and discussed, and the possible attenuation mechanism and strategies are analyzed. Finally, some challenges faced by such catalysts and their prospects are proposed to shed some light on the future development trend of TM-H-C materials for advanced ORR catalysis.

show abstract

Section: Improvement Strategies For Stabilitymentioning

confidence: 99%

mentioning

confidence: 99%

Stabilizing Fe–N–C Catalysts as Model for Oxygen Reduction Reaction

et al. 2021

View full text Add to dashboard Cite

show abstract

“…[126] Some researches also revealed that, during ORR, spontaneous OH coordination on active site optimized the electronic structure of metal center and weaken its ability to associate with O-intermediates. [127][128][129] In alkaline conditions, this axial OH coordinated to metal center during ORR, while no additional OH coordinated intermediates appear in acid conditions, making ORR more active in high pH (Figure 1f). There is another possible route: O 2 → *OOH → 2*OH → *OH → H 2 O, where the 2*OH intermediate means two OH bond with metal center together.…”

Section: Orr Mechanism Pathways On Sacsmentioning

confidence: 99%

“…[127,129,236,237] This finding was also verified by Xie and co-workers, as plotted in Figure 11c, the thermodynamic E onset clearly positive shifted when OH axial group coordinated on both Fe-N 4 and Co-N 4 according to the ORR mechanism with O 2 *. [128] Optimization adsorption strength of the ORR intermediates are responsible for the improvements of ORR performance, especially in reduce energy absorption for RDS. Figure 11d reveals that OH ligands coordinate on Fe-N 4 and Co-N 4 can downshift d-band centers, thus weaken the ORR intermediates adsorptions to boost ORR performance.…”

Section: Axial Guest Groupsmentioning

confidence: 99%

See 1 more Smart Citation

Recent Developments of Microenvironment Engineering of Single‐Atom Catalysts for Oxygen Reduction toward Desired Activity and Selectivity

Huang

Tang

et al. 2021

Adv Funct Materials

108

View full text Add to dashboard Cite

Oxygen reduction reaction (ORR) is an essential process for sustainable energy supply and sufficient chemical production in modern society. Singleatom catalysts (SACs) exhibit great potential on maximum atomic efficiency, high ORR activity, and stability, making them attractive candidates for pursuing next-generation catalysts. Despite substantial efforts being made on building diversiform single-atom active sites (SAASs), the performance of the obtained catalysts is still unsatisfactory. Fortunately, microenvironment regulation of SACs provides opportunities to improve activity and selectivity for ORR. In this review, first, ORR mechanism pathways on N-coordinated SAAS, electrochemical evaluation, and characterization of SAAS are displayed. In addition, recent developments in tuning microenvironment of SACs are systematically summarized, especially, strategies for microenvironment modulation are introduced in detail for boosting the intrinsic 4e − /2e − ORR activity and selectivity. Theoretical calculations and cutting-edge characterization techniques are united and discussed for fundamental understanding of the synthesis-construction-performance correlations. Furthermore, the techniques for building SAAS and tuning their microenvironment are comprehensively overviewed to acquire outstanding SACs. Lastly, by proposing perspectives for the remaining challenges of SACs and infant microenvironment engineering, the future directions of ORR SACs and other analogous procedures are pointed out.

show abstract

Relay Catalysis of Multi‐Sites Promotes Oxygen Reduction Reaction

Luo

Wang

et al. 2023

Adv Funct Materials

View full text Add to dashboard Cite

The two‐electron pathway to form hydrogen peroxide (H2O2) is undesirable for the oxygen reduction reaction (ORR) in iron and nitrogen doped carbon (Fe–N–C) material as it not only lowers the catalytic efficiency but also impairs the catalyst durability. In this study, a relay catalysis pathway is designed to minimize the two‐electron selectivity of Fe–N–C catalyst. Such a design is achieved by introducing two other sites, that is, MnN4 site and α‐Fe(110) face. A combination of transmission electron microscopy image and X‐ray absorption spectra verify the three site formation. Electrochemical test coupled with post‐treatment confirm the improvement of MnN4 site and α‐Fe(110) face on catalyst performance. Theoretical calculation proposes a relay catalysis pathway of three sites, that is, H2O2 released from the FeN4 site migrates to the MnN4 site or α‐Fe(110) face, on which the captive H2O2 is further reduced to H2O. The relay catalysis pathway positioned the as‐prepared catalyst among the best ORR catalysts in both aqueous electrode and alkaline direct methanol fuel cell test. This study examples an interesting relay catalysis pathway of multi‐sites for the ORR, which offers insights into the design of efficient electrocatalysts for fuel cells or beyond.

show abstract

Axial ligand effect on the stability of Fe–N–C electrocatalysts for acidic oxygen reduction reaction

Cited by 66 publications

References 45 publications

Stabilizing Fe–N–C Catalysts as Model for Oxygen Reduction Reaction

Stabilizing Fe–N–C Catalysts as Model for Oxygen Reduction Reaction

Recent Developments of Microenvironment Engineering of Single‐Atom Catalysts for Oxygen Reduction toward Desired Activity and Selectivity

Relay Catalysis of Multi‐Sites Promotes Oxygen Reduction Reaction

Contact Info

Product

Resources

About