Coordination tuning of cobalt phosphates towards efficient water oxidation catalyst

Hyunah Kim, Jimin Park, Inchul Park, Kyoungsuk Jin, Sung Eun Jerng, Sun Hee Kim, Ki Tae Nam, Kisuk Kang

Research output: Contribution to journalArticlepeer-review

254 Citations (Scopus)

Abstract

The development of efficient and stable water oxidation catalysts is necessary for the realization of practically viable water-splitting systems. Although extensive studies have focused on the metal-oxide catalysts, the effect of metal coordination on the catalytic ability remains still elusive. Here we select four cobalt-based phosphate catalysts with various cobalt- and phosphate-group coordination as a platform to better understand the catalytic activity of cobalt-based materials. Although they exhibit various catalytic activities and stabilities during water oxidation, Na 2 CoP 2 O 7 with distorted cobalt tetrahedral geometry shows high activity comparable to that of amorphous cobalt phosphate under neutral conditions, along with high structural stability. First-principles calculations suggest that the surface reorganization by the pyrophosphate ligand induces a highly distorted tetrahedral geometry, where water molecules can favourably bind, resulting in a low overpotential (1/40.42 €‰eV). Our findings emphasize the importance of local cobalt coordination in the catalysis and suggest the possible effect of polyanions on the water oxidation chemistry.

Original languageEnglish
Article number8253
JournalNature communications
Volume6
DOIs
Publication statusPublished - 2015 Sep 14
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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