Crystallinity-modulated Co2-xVxO4 Nanoplates for Efficient Electrochemical Water Oxidation

Chaoran Jiang, Ji Yang, Xiaoyu Han, Haifeng Qi, Min Su, Deqiang Zhao, Leilei Kang, Xiaoyan Liu, Jianfeng Ye, Jianfeng Li, Zheng-Xiao Guo, Nikolas Kaltsoyannis, Aiqin Wang, Junwang Tang

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Abstract

Cost-efficient and durable oxygen evolution catalysts are in great demand, which are dominated not only by the component of the electrocatalysts but also by their molecular structure and crystallinity. Herein, we developed an efficient cobalt–vanadium spinel-type electrocatalyst with an extremely high concentration of Co 3+ ions by tuning the balanced vanadium ions’ concentration in crystallinity-modulated Co 2–xV xO 4 nanoplates. This resulted in the lowest overpotential of 240 mV at 10 mA/cm 2, the smallest Tafel slope of 45 mV dec –1, and a current density of 100 mA/cm 2 at an overpotential of 280 mV for water oxidation, which is remarkably 20 times better than that of the benchmark RuO 2 catalyst, along with excellent stability. Such excellent performance is due to the very high Co 3+/Co 2+ ratio of 2.84 achieved in situ in the low-crystallinity Co 2–xV xO 4 (LC-Co 2–xV xO 4) sample, which is 40% higher than that of the widely reported Co 3O 4, as evidenced by both operando X-ray absorption near-edge spectroscopy and in situ X-ray photoelectron spectroscopy. These findings stimulate the opportunities to explore Co 2–xV xO 4 as a class of nonprecious-metal-based efficient OER electrocatalysts.

Original languageEnglish
Pages (from-to)14884-14891
Number of pages8
JournalACS Catalysis
Volume21
DOIs
Publication statusPublished - 17 Dec 2021

Keywords

  • cobalt−vanadium cluster
  • crystallinity
  • electrocatalysts
  • nanoplates
  • water oxidation

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