Thermally reduced rGO-wrapped CoP/Co2P hybrid microflower as an electrocatalyst for hydrogen evolution reaction

Taek Seung Kim, Hee Jo Song, Mushtaq Ahmad Dar, Hyun Woo Shim, Dong Wan Kim

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Cobalt phosphides (CoPx) are potential candidates for use as high-efficiency hydrogen evolution reaction electrocatalysts that can replace noble metals, such as Pt. Typically, CoPx can be synthesized by phosphidation with Co-based precursors such as oxides or hydroxides. In this study, we propose a new strategy for synthesizing CoPx through the thermal reduction in cobalt phosphate (Co3(PO4)2). A reduced graphene oxide-wrapped CoP/Co2P hybrid microflower was successfully synthesized by a facile coprecipitation method in a Co3(PO4)2 matrix, followed by a thermal reduction process. Co3(PO4)2 can be transformed to CoP/Co2P by treatment at 700°C for 1 hour, maintaining the original particle morphology with the assistance of reduced graphene oxide (rGO). In a 0.5 mol/L H2SO4 solution, the rGO-CoP/Co2P microflower catalyzes the hydrogen evolution reaction with an overpotential of 156 mV at a current density of 10 mA cm−2, a Tafel slope of 53.8 mV dec−1, and good stability as observed through long-term CV and chronoamperometry tests.

Original languageEnglish
Pages (from-to)3749-3754
Number of pages6
JournalJournal of the American Ceramic Society
Issue number9
Publication statusPublished - 2018 Sep


  • catalysts/catalysis
  • cobalt/cobalt compounds
  • graphene oxide
  • hydrogen evolution reaction
  • phosphates

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry


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