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Oxygen Evolution and Reduction Reaction Activity Investigations on Fe, Co or Ni embedded Tetragonal Graphene by A Thermodynamical Full-Landscape Searching Scheme.

ABSTRACT: Single transition metal (TM) atoms such as Fe, Co and Ni occupying a carbon divacancy in tetragonal graphene (TG) and bonded with four nitrogen atoms (TM@N₄ TG) as electrocatalysts are investigated by means of first-principles calculations. To consider the effect of solvent species on the local configuration of the active single metal, a thermodynamical full-landscape searching (TFLS) scheme is employed. The calculated thermodynamic overpotentials (η_td ) from our TFLS indicate that Co@N₄ TG displays high catalytic activity toward both oxygen evolution reaction (OER) and reduction reaction (ORR), with η_td ^OER and η_td ^ORR as 0.397 and 0.357 V, respectively. Its OER potential cannot be captured if only one four electron reaction loop (FERL) is considered. The actual active pathways do not always turn out to be the reactions starting from the bare site. Our findings demonstrate that TG is a promising support and TM confined TD can be used to design effective and cheap multifunctional electrocatalysts.

SUBMITTER: Gai Y

PROVIDER: S-EPMC8248917 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Synthetic Designs and Structural Investigations of Biomimetic Ni-Fe Thiolates.

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| S-EPMC6379113 | biostudies-literature

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| S-EPMC5746853 | biostudies-literature

Fe@N-Graphene Nanoplatelet-Embedded Carbon Nanofibers as Efficient Electrocatalysts for Oxygen Reduction Reaction.

Project description:An activated carbon nanofiber (CNF) is prepared with incorporated Fe-N-doped graphene nanoplatelets (Fe@NGnPs), via a novel and simple synthesis approach. The activated CNF-Fe@NGnP catalysts exhibit substantially improved activity for the oxygen reduction reaction compared to those of commercial carbon blacks and Pt/carbon catalysts.

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Tetragonal to triclinic--a phase change for [Fe(TPP)(NO)].

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| S-EPMC6003342 | biostudies-literature

In situ formation of molecular Ni-Fe active sites on heteroatom-doped graphene as a heterogeneous electrocatalyst toward oxygen evolution.

Project description:Molecularly well-defined Ni sites at heterogeneous interfaces were derived from the incorporation of Ni2+ ions into heteroatom-doped graphene. The molecular Ni sites on graphene were redox-active. However, they showed poor activity toward oxygen evolution reaction (OER) in KOH aqueous solution. We demonstrated for the first time that the presence of Fe3+ ions in the solution could bond at the vicinity of the Ni sites with a distance of 2.7 Å, generating molecularly sized and heterogeneous Ni-Fe sites anchored on doped graphene. These Ni-Fe sites exhibited markedly improved OER activity. The Pourbaix diagram confirmed the formation of the Ni-Fe sites and revealed that the Ni-Fe sites adsorbed HO- ions with a bridge geometry, which facilitated the OER electrocatalysis.

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