Isolated Single Iron Atoms Anchored on N‐Doped Porous Carbon as an Efficient Electrocatalyst for the Oxygen Reduction Reaction

Chen, Yuanjun; Ji, Shufang; Wang, Yang‐Gang; Dong, Juncai; Chen, Wenxing; Li, Zhi; Shen, Rongan; Zheng, Lirong; Zhuang, Zhongbin; Wang, Dingsheng; Li, Yadong

doi:10.1002/anie.201702473

Cited by 1,701 publications

(1,075 citation statements)

References 34 publications

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“…While this divacancy-based moiety has been explored theoretically for its intriguing electronic, magnetic and catalytic properties 43,44 , it's never been fully identified experimentally, which seriously hampers its fundamental and applied investigations. We note that although several previous experimental studies suggested the divacancy-based MN 4 C 4 moiety 11,12,45,46 , there was insufficient spectroscopic evidence to verify its existence, as such structural assignments were mainly based on EXAFS spectra and none of the previously reported EXAFS spectra could well match with the simulated standard spectra of the divacancy-based MN 4 C 4 moiety (Supplementary Fig. 27).…”

Section: Nature Catalysismentioning

confidence: 80%

General synthesis and definitive structural identification of MN4C4 single-atom catalysts with tunable electrocatalytic activities

et al. 2018

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E fficient and cost-effective electrocatalysts play critical roles in energy conversion and storage [1][2][3] . Homogeneous and heterogeneous catalysts represent two parallel frontiers of electrocatalysts, each with their own merits and drawbacks 4,5 . Homogeneous catalysts are attractive for their highly uniform active sites, tunable coordination environment and maximized atom utilization efficiency, but are limited by their relatively poor stability and recyclability. Heterogeneous catalysts are appealing for their high durability, excellent recyclability, and easy immobilization and integration with electrodes, but usually have rather low atom utilization efficiency due to the limited surface sites accessible to reactants. To this end, considerable efforts have been devoted to developing nanoscale heterogeneous catalysts that can increase the exposed surface atoms 3 . However, the inhomogeneity in the distribution of particle sizes and facets poses a serious challenge for controlling active sites and fundamental mechanistic studies 6,7 . In contrast, homogeneous catalysts typically exhibit the well-defined atomic structure with tunable coordination environment that is essential for deciphering the catalytic reaction pathway and rational design of targeted catalysts with tailored catalytic properties 8 . Single-atom catalysts (SACs) with monodispersed single atoms supported on solid substrates are recently emerging as an exciting class of catalysts that combine the merits of both homogeneous and heterogeneous catalysts [9][10][11][12][13][14] . However, most SACs studied to date employ metal oxides (for example, TiO 2 , CeO 2 and FeO x ) as supporting substrates to prevent atom aggregation [15][16][17][18] , which cannot be readily applied in electrocatalytic applications due to their low electrical conductivity and/or poor stability in harsh liquid-phase electrolytes (for example, strong acid or base). Atomic transitionmetal-nitrogen moieties supported in carbon (M-N-Cs) represent a unique class of SACs with high electrical conductivity and superior (electro)chemical stability for electrocatalytic applications 19 . In particular, Fe-based M-N-Cs have been extensively studied as electrocatalysts towards the oxygen reduction reaction (ORR) with demonstrated activity and stability approaching those of commercial Pt/C catalysts 20,21 . In addition, as suggested by numerous theoretical studies, M-N-Cs are promising candidates for catalysing a wide range of electrochemical processes, such as hydrogen reduction/oxidation 22 , CO 2 /CO reduction 23 and N 2 reduction 24 . A significant advantage of SACs is that the well-defined single atomic site could allow precise understanding of the catalytic reaction pathway, and rational design of targeted catalysts with tailored activity (in a manner similar to homogeneous catalyst design). However, this perceived advantage has been investigated theoretically

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Section: Nature Catalysismentioning

confidence: 80%

General synthesis and definitive structural identification of MN4C4 single-atom catalysts with tunable electrocatalytic activities

et al. 2018

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“…HER is a combination of proton adsorption on catalyst surface via Volmer reaction (H + + e − + * → H*, where * refers to catalysts surface) followed by desorption of H 2 through either Tafel reaction (2H* → H 2 + 2*) or Heyrovsky reaction (H + + e − + H* → H 2 + *). [13][14][15]18] Based on these results we constructed a molecular model of SACs for hydrogen adsorption energy calculation including all possible active sites, namely, graphitic-N, graphitic-C, pyridinic-N, terminal pyridinic-N, pyrrolic-N, and N-oxide species. The free energy change for hydrogen adsorption on the catalyst surface (ΔG H *) determines the kinetics of the HER.…”

Section: Theoretical Activity Prediction Of Sacs For Hermentioning

confidence: 99%

Rational Design of Graphene‐Supported Single Atom Catalysts for Hydrogen Evolution Reaction

Hossain

Liu

Zhuang

et al. 2019

Advanced Energy Materials

335

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The proper choice of nonprecious transition metals as single atom catalysts (SACs) remains unclear for designing highly efficient electrocatalysts for hydrogen evolution reaction (HER). Herein, reported is an activity correlation with catalysts, electronic structure, in order to clarify the origin of reactivity for a series of transition metals supported on nitrogen‐doped graphene as SACs for HER by a combination of density functional theory calculations and electrochemical measurements. Only few of the transition metals (e.g., Co, Cr, Fe, Rh, and V) as SACs show good catalytic activity toward HER as their Gibbs free energies are varied between the range of –0.20 to 0.30 eV but among which Co‐SAC exhibits the highest electrochemical activity at 0.13 eV. Electronic structure studies show that the energy states of active valence dz2 orbitals and their resulting antibonding state determine the catalytic activity for HER. The fact that the antibonding state orbital is neither completely empty nor fully filled in the case of Co‐SAC is the main reason for its ideal hydrogen adsorption energy. Moreover, the electrochemical measurement shows that Co‐SAC exhibits a superior hydrogen evolution activity over Ni‐SAC and W‐SAC, confirming the theoretical calculation. This systematic study gives a fundamental understanding about the design of highly efficient SACs for HER.

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“…[41] However, in order to prevent the agglomeration, credible supports for the uniform distribution of SAs are imperatively needed. [43] ZIF-8 was chosen as cages to separate and encapsulate Fe(acac) 3 which served as SA precursor. Specifically, the Zn-contained bimetallic ZIFs-derived carbon materials have proved promising for SA stabilization, because Zn ions could spatially attenuate the concentration of requisite metal ions, and the evaporation of Zn will generate uncoordinated N atoms, which could serve as coordination sites to bind with SAs.…”

Section: Single Atoms@mof-derived Nanostructuresmentioning

confidence: 99%

Secondary‐Component Incorporated Hollow MOFs and Derivatives for Catalytic and Energy‐Related Applications

2018

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Their highly functional nature has endowed metal-organic frameworks (MOFs) with diverse applications. On this basis, a higher demand has been proposed for the preparation of novel-structured MOFs. Hollow MOFs have been intensively studied and exhibited versatile properties, and among the various methods, secondary-component incorporation has been proved promising in the design and preparation of complex structures with requisite properties. Herein, the synthesis and applications of secondary component incorporated MOFs and their derivatives are systematically reviewed. Two main methodologies, preincorporation and postmodification, are discussed in detail, and the role of the secondary component is demonstrated. Based on these introductions, the applications of those materials, including chemical catalysis, electrocatalysis, and energy storage applications, are summarized. Finally, a personal outlook for the future opportunities and challenges in this field is given.

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Isolated Single Iron Atoms Anchored on N‐Doped Porous Carbon as an Efficient Electrocatalyst for the Oxygen Reduction Reaction

Cited by 1,701 publications

References 34 publications

General synthesis and definitive structural identification of MN4C4 single-atom catalysts with tunable electrocatalytic activities

General synthesis and definitive structural identification of MN4C4 single-atom catalysts with tunable electrocatalytic activities

Rational Design of Graphene‐Supported Single Atom Catalysts for Hydrogen Evolution Reaction

Secondary‐Component Incorporated Hollow MOFs and Derivatives for Catalytic and Energy‐Related Applications

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