Cobalt and Nitrogen Co-Doped Tungsten Carbide Catalyst for Oxygen Reduction and Hydrogen Evolution Reactions. (1st February 2016)

• Record Type: Journal Article
• Authors: Bukola, Saheed; Merzougui, Belabbes; Akinpelu, Akeem; Zeama, Mostafa
• Is Part Of: Electrochimica acta. Volume 190(2016)
• Page Start: 1113
• Page End: 1123
• Publication Date: 2016-02-01
• Subjects: Oxygen reduction reaction -- hydrogen evolution reaction -- tungsten carbide -- methanol tolerance -- bi-functional catalyst; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.12.074
• Languages: English
• ISSNs: 0013-4686

Abstract

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 H2 O2 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.