Cobalt and Nitrogen Co-Doped Tungsten Carbide Catalyst for Oxygen Reduction and Hydrogen Evolution Reactions

Saheed Bukola, Belabbes Merzougui, Akeem Akinpelu, Mostafa Zeama

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34 Citations (Scopus)

Abstract

We have serendipitously facile developed a dual-performing electrocatalyst for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) by co-doped cobalt and nitrogen on tungsten carbide matrix. Its improved ORR and HER activities in 0.1 M KOH were confirmed using a thin-film rotating ring-disk electrode (TF-RRDE) and electrochemical impedance spectroscopy (EIS). The exchange current density and Tafel slope obtained from EIS data for HER are 1.6 × 10-2 mA cm-2. and ∼43 mV dec-1 respectively, suggesting Volmer-Heyrovsky mechanism for HER. In addition to its good durability for both cathodic processes, catalyst shows a 4-electron transfer process for ORR, excellent tolerance towards methanol oxidation, and low H2O2 formation (∼3.0%). At half-wave potential of ∼0.8 V, no significant degradation was observed after 10,000 (0.65 - 1.0 V) potential cycles in oxygen saturated medium. A catalyst of such benign properties is highly indispensable for energy conversion systems.

Original languageEnglish
Pages (from-to)1113-1123
Number of pages11
JournalElectrochimica Acta
Volume190
DOIs
Publication statusPublished - 1 Feb 2016

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Keywords

  • bi-functional catalyst
  • hydrogen evolution reaction
  • methanol tolerance
  • Oxygen reduction reaction
  • tungsten carbide

ASJC Scopus subject areas

  • Electrochemistry
  • Chemical Engineering(all)

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