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This content will become publicly available on January 15, 2019

Title: Colloidal Cobalt Phosphide Nanocrystals as Trifunctional Electrocatalysts for Overall Water Splitting Powered by a Zinc–Air Battery

Highly efficient and stable electrocatalysts, particularly those that are capable of multifunctionality in the same electrolyte, are in high demand for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this paper, highly monodisperse CoP and Co 2P nanocrystals (NCs) are synthesized using a robust solution-phase method. The highly exposed (211) crystal plane and abundant surface phosphide atoms make the CoP NCs efficient catalysts toward ORR and HER, while metal-rich Co 2P NCs show higher OER performance owing to easier formation of plentiful Co 2P@COOH heterojunctions. Density functional theory calculation results indicate that the desorption of OH* from cobalt sites is the rate-limiting step for both CoP and Co 2P in ORR and that the high content of phosphide can lower the reaction barrier. A water electrolyzer constructed with a CoP NC cathode and a Co 2P NC anode can achieve a current density of 10 mA cm -2 at 1.56 V, comparable even to the noble metal-based Pt/C and RuO 2/C pair. Finally and furthermore, the CoP NCs are employed as an air cathode in a primary zinc–air battery, exhibiting a high power density of 62 mW cm -2 and good stability.
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  1. Wake Forest Univ., Winston-Salem, NC (United States). Dept. of Chemistry
  2. IBM TJ Watson Research Center, Yorktown Heights, NY (United States). Physical Science Division
  3. Harbin Inst. of Technology, Shenzhen (China). Shenzhen Graduate School. Dept. of Materials Science and Engineering. Shenzhen Engineering Lab. of Flexible Transparent Conductive Films
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Material Science and Technology Division
  5. Wake Forest Univ., Winston-Salem, NC (United States). Dept. of Physics. Center for Nanotechnology and Molecular Materials
  6. Soochow Univ., Suzhou (China). Inst. of Functional Nano and Soft Materials
  7. High Point Univ., NC (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
AC05-00OR22725; CHE-1531698
Accepted Manuscript
Journal Name:
Advanced Materials
Additional Journal Information:
Journal Volume: 30; Journal Issue: 9; Journal ID: ISSN 0935-9648
Research Org:
Wake Forest Univ., Winston-Salem, NC (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE; Wake Forest Univ. (United States); National Science Foundation (NSF)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; cobalt phosphide; density functional theory; overall water splitting; trifunctional electrocatalysts; zinc-air batteries
OSTI Identifier: