Chrysanthemum-Like CoP Nanostructures on Vertical Graphene Nanohills as Versatile Electrocatalysts for Water Splitting

Linh Truong, Sahng Kyoon Jerng, Sanjib Baran Roy, Jae Ho Jeon, Kiwoong Kim, Kamran Akbar, Yeonjin Yi, Seung Hyun Chun

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Abstract

CoP is a promising catalyst material to replace noble metals in water electrolysis. To further explore the potential of CoP in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), we utilize vertical graphene nanohills (VGNHs) that are known to enhance catalytic performances through superaerophobicity. Unique CoP chrysanthemum-like structures are formed on VGNHs through a facile, one-step electrodeposition reaction. Because of the highly conductive VGNH support and the modified CoP nanostructures, the optimized CoP/VGNHs hybrid catalyst exhibits excellent electrocatalytic activities toward HER in 0.5 M H 2 SO 4 , such as a low overpotential at 10 mA cm -210 ) of 51 mV, a small Tafel slope of 36 mV dec -1 , and a long-term stability. Specifically, the overpotential at 100 mA cm -2100 ) is merely 125 mV, an outstanding performance for a noble metal-free catalyst. Furthermore, the HER performance in 1.0 M KOH (η 10 of 93 mV) and the OER performance in the same alkaline medium (η 10 of 300 mV) are highly competitive, making CoP/VGNHs also an excellent bifunctional electrocatalyst yielding a current density of 10 mA cm -2 at a low voltage of 1.63 V. This novel nanostructure offers an efficient strategy for the development of nonprecious metal catalysts for water electrolysis.

Original languageEnglish
Pages (from-to)4625-4630
Number of pages6
JournalACS Sustainable Chemistry and Engineering
Volume7
Issue number5
DOIs
Publication statusPublished - 2019 Mar 4

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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