Issue 3, 2016

Direct electrochemical formation of nanostructured amorphous Co(OH)2 on gold electrodes with enhanced activity for the oxygen evolution reaction

Abstract

The oxides of cobalt have recently been shown to be highly effective electrocatalysts for the oxygen evolution reaction (OER) under alkaline conditions. In general species such as Co3O4 and CoOOH have been investigated that often require an elevated temperature step during their synthesis to create crystalline materials. In this work we investigate the rapid and direct electrochemical formation of amorphous nanostructured Co(OH)2 on gold electrodes under room temperature conditions which is a highly active precursor for the OER. During the OER some conversion to crystalline Co3O4 occurs at the surface, but the bulk of the material remains amorphous. It is found that the underlying gold electrode is crucial to the materials enhanced performance and provides higher current density than can be achieved using carbon, palladium or copper support electrodes. This catalyst exhibits excellent activity with a current density of 10 mA cm−2 at an overpotential of 360 mV with a high turnover frequency of 2.1 s−1 in 1 M NaOH. A Tafel slope of 56 mV dec−1 at low overpotentials and a slope of 122 mV dec−1 at high overpotentials is consistent with the dual barrier model for the electrocatalytic evolution of oxygen. Significantly, the catalyst maintains excellent activity for up to 24 h of continuous operation and this approach offers a facile way to create a highly effective and stable material.

Graphical abstract: Direct electrochemical formation of nanostructured amorphous Co(OH)2 on gold electrodes with enhanced activity for the oxygen evolution reaction

Supplementary files

Article information

Article type
Paper
Submitted
11 Nov 2015
Accepted
03 Dec 2015
First published
03 Dec 2015
This article is Open Access
Creative Commons BY-NC license

J. Mater. Chem. A, 2016,4, 991-999

Author version available

Direct electrochemical formation of nanostructured amorphous Co(OH)2 on gold electrodes with enhanced activity for the oxygen evolution reaction

M. A. Sayeed, T. Herd and A. P. O'Mullane, J. Mater. Chem. A, 2016, 4, 991 DOI: 10.1039/C5TA09125J

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