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In situ unraveling surface reconstruction of Ni-CoP nanowire for excellent alkaline water electrolysis
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  • Haiquan Liu,
  • Sihang Hu,
  • Baojun Long,
  • Huan Dai,
  • Yafei Yang,
  • Menghua Yang,
  • Qi Zhang,
  • Zunjian Ke,
  • Wenqing Li,
  • Dong He,
  • Ziyu Wang,
  • Xiangheng Xiao
Haiquan Liu
Wuhan University
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Sihang Hu
Wuhan University
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Baojun Long
Wuhan University
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Huan Dai
Wuhan University
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Yafei Yang
Wuhan University
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Menghua Yang
Wuhan University
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Qi Zhang
Wuhan University
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Zunjian Ke
Wuhan University
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Wenqing Li
Wuhan University
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Dong He
Wuhan University

Corresponding Author:hedong@whu.edu.cn

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Ziyu Wang
Wuhan University
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Xiangheng Xiao
Wuhan University
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Abstract

The surface reconstruction behavior of transition metal phosphides (TMPs) precursors is considered an important method to prepare efficient oxygen evolution catalysts, but there are still significant challenges in guiding catalyst design at the atomic scale. Here, the CoP nanowire with excellent water splitting performance and stability is used as a catalytic model to study the reconstruction process. Obvious double redox signals and valence evolution behavior of the Co site are observed, corresponding to Co2+/Co3+ and Co3+/Co4+ caused by auto-oxidation process. Importantly, the in-situ Raman spectrum exhibits the vibration signal of Co-OH in the non-Faradaic potential interval for oxygen evolution reaction, which is considered the initial reconstruction step . Density functional theory and ab initio molecular dynamics are used to elucidate this process at the atomic scale: First, OH- exhibits a lower adsorption energy barrier and proton desorption energy barrier at the configuration surface, which proposes the formation of a single oxygen group. Under a higher -O group coverage, the Co-P bond is destroyed along with the POx groups. Subsequently, lower P vacancy formation energy confirm that the Ni-CoP configuration can fast transform into highly active phase. Based on optimized reconstruction behavior and rate-limiting barrier, the Ni-CoP exhibit an excellent overpotential of 236 mV for OER and 1.59 V for overall water splitting at 10 mA cm-2, which demonstrates low degradation (2.62 %) during the 100 mA cm-2 for 100 h. This work provide systematic insights into the atomic-level reconstruction mechanism of TMPs, which benefit further design of water splitting catalyst.
19 May 2024Submitted to Energy & Environmental Materials
30 May 2024Review(s) Completed, Editorial Evaluation Pending
08 Jun 2024Reviewer(s) Assigned
07 Jul 2024Editorial Decision: Revise Major
01 Aug 20241st Revision Received
01 Aug 2024Submission Checks Completed
01 Aug 2024Assigned to Editor
01 Aug 2024Review(s) Completed, Editorial Evaluation Pending
04 Aug 2024Reviewer(s) Assigned
26 Aug 2024Editorial Decision: Revise Minor
28 Aug 20242nd Revision Received
30 Aug 2024Submission Checks Completed
30 Aug 2024Assigned to Editor
30 Aug 2024Review(s) Completed, Editorial Evaluation Pending
30 Aug 2024Editorial Decision: Accept