Surface Charge and Electrostatic Spin Crossover Effects in CoN<sub>4</sub> Electrocatalysts

Duan, Zhiyao; Henkelman, Graeme

doi:10.1021/acscatal.0c02458

Cited by 104 publications

(99 citation statements)

References 46 publications

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“…This implies that the isolated Fe sites are the dominating active species for ORR 40 . The high ORR performance of Fe sites is related to their stronger bonding affinity of Fe centers toward O 2 molecules 41 , 42 , which is in line with previous literature 19 , 43 . To further elucidate the ORR process, Koutecky–Levich (K–L) equation and rotation ring-disk electrode (RRDE) tests were carried out.…”

Section: Resultssupporting

confidence: 90%

Mechanistic insight into the active centers of single/dual-atom Ni/Fe-based oxygen electrocatalysts

et al. 2021

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Single-atom catalysts with maximum metal utilization efficiency show great potential for sustainable catalytic applications and fundamental mechanistic studies. We here provide a convenient molecular tailoring strategy based on graphitic carbon nitride as support for the rational design of single-site and dual-site single-atom catalysts. Catalysts with single Fe sites exhibit impressive oxygen reduction reaction activity with a half-wave potential of 0.89 V vs. RHE. We find that the single Ni sites are favorable to promote the key structural reconstruction into bridging Ni-O-Fe bonds in dual-site NiFe SAC. Meanwhile, the newly formed Ni-O-Fe bonds create spin channels for electron transfer, resulting in a significant improvement of the oxygen evolution reaction activity with an overpotential of 270 mV at 10 mA cm−2. We further reveal that the water oxidation reaction follows a dual-site pathway through the deprotonation of *OH at both Ni and Fe sites, leading to the formation of bridging O2 atop the Ni-O-Fe sites.

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Section: Resultssupporting

confidence: 90%

Mechanistic insight into the active centers of single/dual-atom Ni/Fe-based oxygen electrocatalysts

et al. 2021

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“…In this case, the number of electrons transferred may deviate significantly from the number of H stripped/added. This effect has already been identified previously by theoretical studies considering constant-potential effects and it is used to explain pH-dependent electrocatalytic activity and selectivity, − atomic structures of active sites, − and electrostatic spin transitions in single-atom electrocatalyts, and so forth.…”

Section: Resultsmentioning

confidence: 67%

Simulation of Potential-Dependent Activation Energies in Electrocatalysis: Mechanism of O–O Bond Formation on RuO₂

Duan

Xiao

2021

J. Phys. Chem. C

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Theoretical assessment of potential-dependent activation energies of electrochemical reactions is of critical importance but remains challenging. In this work, we present two computational tools to tackle this long-standing challenge. First, we implement a general computational framework for constant-potential saddle searches including both atomic positions and number of electrons as variables. Second, we develop a novel correction method to determine potential-dependent activation energies based on conventional zero-charge calculations. Different from existing capacitance-only schemes, our correction method takes into account the potential-dependent structural relaxation. This correction allows a significant reduction in computational overhead, but is still quite accurate, supplementing the direct constant-potential simulation. With these tools, we study the O–O bond formation reaction on the RuO2(110) surface. A number of new mechanistic insights are developed from the constant-potential calculations. The proton-coupled electron transfer pathway for the O–O bond formation has been determined to be favorable over the water dissociation mechanism. It is found that both H atoms strip from H2O successively to directly form adsorbed O2 without forming a stable intermediate OOH. With this example, we also demonstrate that the charge-structure coupling effect is not always negligible and can be captured by the full-Hessian correction. We expect the methods developed here to become useful tools in electrocatalysis.

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“…For example, Kim et al theoretically showed that the system charge significantly affects the activity of 2D electrocatalysts with atomic thickness . To this end, we also utilized the constant-potential method developed by Duan et al − to explore the effects of U and pH values on the ORR activity of 2D biphenylene (see the Supporting Information for the computational details). As disclosed above, OOH* formation is the potential-limiting step, suggesting that the ORR activity of 2D biphenylene is actually governed by the adsorption free energy of OOH* species (Δ G OOH* ).…”

mentioning

confidence: 99%

Two-Dimensional Biphenylene: A Graphene Allotrope with Superior Activity toward Electrochemical Oxygen Reduction Reaction

Liu

Jing

2021

J. Phys. Chem. Lett.

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Developing efficient and inexpensive catalysts for the oxygen reduction reaction (ORR) is a key for sustainable development of fuel cell technologies. Herein, by means of density functional theory calculations and microkinetic modeling, we demonstrate that two-dimensional (2D) biphenylene, a recently synthesized allotrope of graphene composed of tetragonal, hexagonal, and octagonal rings, is a metal-free candidate for facilitating the electrochemical ORR. Different from semimetallic graphene, 2D biphenylene is metallic, and carbon atoms of its tetragonal rings are substantially positively charged, resulting in good ORR activity due to the enhanced binding strength with reaction intermediates. In particular, the ORR activity of 2D biphenylene is pH-dependent, and it can be significantly boosted under alkaline conditions. Moreover, 2D biphenylene possesses rather good electrochemical stability, rendering it attractive for alkaline fuel cells.

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Surface Charge and Electrostatic Spin Crossover Effects in CoN₄ Electrocatalysts

Cited by 104 publications

References 46 publications

Mechanistic insight into the active centers of single/dual-atom Ni/Fe-based oxygen electrocatalysts

Mechanistic insight into the active centers of single/dual-atom Ni/Fe-based oxygen electrocatalysts

Simulation of Potential-Dependent Activation Energies in Electrocatalysis: Mechanism of O–O Bond Formation on RuO₂

Two-Dimensional Biphenylene: A Graphene Allotrope with Superior Activity toward Electrochemical Oxygen Reduction Reaction

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Surface Charge and Electrostatic Spin Crossover Effects in CoN4 Electrocatalysts

Cited by 104 publications

References 46 publications

Mechanistic insight into the active centers of single/dual-atom Ni/Fe-based oxygen electrocatalysts

Mechanistic insight into the active centers of single/dual-atom Ni/Fe-based oxygen electrocatalysts

Simulation of Potential-Dependent Activation Energies in Electrocatalysis: Mechanism of O–O Bond Formation on RuO2

Two-Dimensional Biphenylene: A Graphene Allotrope with Superior Activity toward Electrochemical Oxygen Reduction Reaction

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Surface Charge and Electrostatic Spin Crossover Effects in CoN₄ Electrocatalysts

Simulation of Potential-Dependent Activation Energies in Electrocatalysis: Mechanism of O–O Bond Formation on RuO₂