Surface galvanic formation of Co-OH on Birnessite and its catalytic activity for the oxygen evolution reaction

Yayun Pu, Veronica Celorrio, Jöerg M. Stockmann, Oded Sobol, Zongzhao Sun, Wu Wang, Matthew J. Lawrence, Jörg Radnik, Andrea E. Russell, Vasile Dan Hodoroaba, Limin Huang, Paramaconi Rodriguez

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Low-cost, high-efficient catalysts for water splitting can be potentially fulfilled by developing earth-abundant metal oxides. In this work, surface galvanic formation of Co-OH on K0.45MnO2 (KMO) was achieved via the redox reaction of hydrated Co2+ with crystalline Mn4+. The synthesis method takes place at ambient temperature without using any surfactant agent or organic solvent, providing a clean, green route for the design of highly efficient catalysts. The redox reaction resulted in the formation of ultrathin Co-OH nanoflakes with high electrochemical surface area. X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the changes in the oxidation state of the bulk and surface species on the Co-OH nanoflakes supported on the KMO. The effect of the anions, such as chloride, nitrate and sulfate, on the preparation of the catalyst was evaluated by electrochemical and spectrochemical means. XPS and Time of flight secondary ion mass spectrometry (ToF-SIMS) analysis demonstrated that the layer of CoOxHy deposited on the KMO and its electronic structure strongly depend on the anion of the precursor used during the synthesis of the catalyst. In particular, it was found that Cl- favors the formation of Co-OH, changing the rate-determining step of the reaction, which enhances the catalytic activity towards the OER, producing the most active OER catalyst in alkaline media.

Original languageEnglish
Pages (from-to)304-314
Number of pages11
JournalJournal of Catalysis
Volume396
DOIs
StatePublished - 1 Apr 2021
Externally publishedYes

Keywords

  • Anion effect
  • Layered manganese oxide
  • Oxygen evolution reaction
  • Surface galvanic synthesis

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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