Operando unraveling of the structural and chemical stability of P-substituted CoSe 2 electrocatalysts toward hydrogen and oxygen evolution reactions in alkaline electrolyte

Yanping Zhu, Hsiao Chien Chen, Chia Shuo Hsu, Ting Sheng Lin, Chia Jui Chang, Sung Chun Chang, Li Duan Tsai, Hao Ming Chen

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106 Citations (Scopus)

Abstract

The question of whether the metal chalcogenides (phosphides) that have been acknowledged to be efficient materials for bifunctional electrocatalysts really perform as the active species or just "pre-catalysts" has been debated. Herein, a series of operando measurements, including in situ X-ray absorption spectroscopy, liquid-phase transmission electron microscopy, and in situ Raman spectroscopy, were conducted to unravel in real time the structural and chemical stability of P-substituted CoSe 2 electrocatalysts under both hydrogen and oxygen evolution reactions (HER and OER, respectively) in an alkaline electrolyte. It can be conclusively revealed that, in an alkaline electrolyte, the P-substituted CoSe 2 electrocatalyst was acting as the "pre-catalyst" rather than the real reactive species. The introduction of phosphorus is speculated to generate more vacancies or defects around Co cations in the initial CoSe 2 and considerably facilitates the structural transformation into the "real reactive species", such as metallic cobalt (for HER) and cobalt oxyhydroxide (for OER).

Original languageEnglish
Pages (from-to)987-994
Number of pages8
JournalACS Energy Letters
Volume4
Issue number4
DOIs
Publication statusPublished - 2019 Apr 12

All Science Journal Classification (ASJC) codes

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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