Self-reconstruction mechanism in NiSe 2 nanoparticles/carbon fiber paper bifunctional electrocatalysts for water splitting

Lingling Zhai, Chun Hin Mak, Jiasheng Qian, Shenghuang Lin, Shu Ping Lau

Research output: Journal article publicationJournal articleAcademic researchpeer-review

23 Citations (Scopus)

Abstract

Developing efficient bifunctional electrocatalysts and gaining fundamental understanding of reaction mechanisms are crucial for practical water splitting. Herein, a bifunctional NiSe 2 nanoparticles/carbon fiber paper (NSN/CFP) electrode is fabricated by the pyrolysis of Ni(NO 3 ) 2 on CFP, followed by a selenization step. The as-prepared electrocatalysts exhibit superior overall water splitting behavior in 1 M KOH with low overpotentials of 145 mV and 280 mV at current densities of 10 mA cm −2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) respectively, comparable to the performance of 20% Pt/C and RuO 2 . Detailed compositional and morphological studies reveal that the NiSe 2 gradually transforms into an amorphous Ni(OH) 2 /NiOOH heterojunction during both HER and OER in alkaline medium. Based on these experimental results, an oxidation-induced self-reconstruction mechanism is proposed. Owing to the highly-oxidized Ni(OH) 2 /NiOOH active species, the self-reconstructed structure enhances the water splitting under fixed potentials for a prolonged time of 96 h with negligible current degradation. This work not only provides a facile route to fabricate efficient and stable electrocatalysts for large-scale water splitting but also reveals an underlying structural evolution mechanism, which guides the rational design of heterogeneous catalysts.

Original languageEnglish
Pages (from-to)37-46
Number of pages10
JournalElectrochimica Acta
Volume305
DOIs
Publication statusPublished - 10 May 2019

Keywords

  • Bifunctional electrocatalyst
  • Hydrogen evolution reaction
  • Nickel diselenide
  • Oxygen evolution reaction
  • Water splitting

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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