Alkaline oxygen evolution: exploring synergy between fcc and hcp cobalt nanoparticles entrapped in N-doped graphene

Ajit Kumar Singh, Seulgi Ji, Baghendra Singh, Chittaranjan Das, Heechae Choi*, Prashanth W. Menezes*, Arindam Indra*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Herein, we report a Mott-Schottky catalyst by entrapping cobalt nanoparticles inside the N-doped graphene shell (Co@NC). The Co@NC delivered excellent oxygen evolution activity with an overpotential of merely 248 mV at a current density of 10 mA cm–2 with promising long-term stability. The importance of Co encapsulated in NC has further been demonstrated by synthesizing Co nanoparticles without NC shell. The synergy between the hexagonal close-packed (hcp) and face-centered cubic (fcc) Co plays a major role to improve the OER activity, whereas the NC shell optimizes the electronic structure, improves the electron conductivity, and offers a large number of active sites in Co@NC. The density functional theory calculations have revealed that the hcp Co has a dominant role in the surface reaction of electrocatalytic oxygen evolution, whereas the fcc phase induces the built-in electric field at the interfaces with N-doped graphene to accelerate the H+ ion transport.

Original languageEnglish
Article number100668
JournalMaterials Today Chemistry
Volume23
DOIs
Publication statusPublished - Mar 2022
Externally publishedYes

Keywords

  • Co nanoparticles
  • Core-shell structure
  • Nitrogen doped graphene
  • Phase effect
  • Water oxidation

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