Realizing Efficient Overall Water Splitting by Tuning the Cobalt Content in Self-Supported Nix−Coy−P Microarrays

Xiong Xiong LIU, Qian HE, Shuhao XIAO, Xinran LI, Le CHANG, Yong XIANG, Ke HU, Xiaobin NIU, Rui WU*, Jun Song CHEN*

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

7 Citations (Scopus)

Abstract

Transition-metal phosphides have been identified as a group of promising catalysts, especially for the hydrogen evolution reaction (HER). However, their practical application is still hindered by the suboptimal activity and tedious preparation. In this work, self-supported transition-metal phosphide microarrays have been synthesized on Ni foam via electrodeposition followed by a low-temperature gaseous phosphorization. We discover that Ni2P or Nix−Coy−P can be obtained with tunable composition. Among the obtained phosphides with different Ni and Co contents, Ni1−Co1−P exhibits a low overpotential of only 90 mV at 10 mA cm−2 for HER in 1 M KOH, whereas that of Ni2P is as high as 137 mV. Furthermore, Ni1-Co1-P also demonstrates a current density of 10 mA cm−2 at an overpotential of only 292 mV for the oxygen evolution reaction (OER). An overall water splitting device has been assembled with two Ni1−Co1−P electrodes, and it displays an excellent performance at 1.65 V for a current density of 20 mA cm−2 with a good stability up to 30 h. The density functional theory calculation results suggest that by incorporating Co into the phosphide, the surface electronic structure of Ni1-Co1-P has been optimized, showing a much smaller Gibbs free energy change of absorbed intermediates during the HER and OER than Ni2P. Considering the ease in fabrication and the superior performance, this material displays good potential for industrial applications at a large scale.

Original languageEnglish
Pages (from-to)1307-1315
Number of pages9
JournalChemElectroChem
Volume8
Issue number7
Early online date9 Feb 2021
DOIs
Publication statusPublished - 1 Apr 2021
Externally publishedYes

Bibliographical note

This work was financially supported by Fundamental Research Funds for the Central Universities (ZYGX2019 J030) and FPC Topsun-UESTC-Research project (200019).

Keywords

  • bifunctional catalysts
  • electrodeposition
  • facile preparation
  • Ni-Co-P
  • overall water splitting

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