Ethanol electrooxidation in alkaline medium on electrochemically synthesized Co(OH) sub(2)/Au composite

• Published in: Materials research express 2017-01, Vol.4 (1), p.016408-016408
• Main Authors: Babu, Sreejith P, Elumalai, Perumal
• Format: Article
• Language: English
• Subjects: Anodizing; Deposits; Electrodes; Ethanol; Ethyl alcohol; Gold; Morphology; Scanning electron microscopy
• ISSN: 2053-1591; 2053-1591
• DOI: 10.1088/2053-1591/aa5665

Gold (Au), cobalt hydroxide (Co(OH) sub(2)) and different Co(OH) sub(2)/Au compositions were electro-deposited onto stainless steel by a potentiodynamic method from the respective metal-ion solutions. The deposits were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transformed infra-red spectroscopy (FT-IR). The XRD and IR data confirmed that the deposits were Au, [alpha]-Co(OH) sub(2) or Co(OH) sub(2)/Au composites. The SEM observations confirmed that the morphology of the Au was spherical, while the [alpha]-Co(OH) sub(2) was flakey with pores. The morphology of the Co(OH) sub(2)/Au composites consisted of highly agglomerated Au grains distributed on the Co(OH) sub(2) matrix. The electrocatalytic activity of each of the Au, Co(OH) sub(2) and Co(OH) sub(2)/Au-composite electrodes towards ethanol electrooxidation in an alkaline medium was investigated by cyclic voltammetry and chronoamperometry. It turned out that the Co(OH) sub(2)/Au-composite electrodes exhibited superior catalytic activity for ethanol electrooxidation compared with the pristine Au or Co(OH) sub(2) electrodes. A peak current density as high as 25 mA cm super(-2) was exhibited by the Co(OH) sub(2)/ Au composite while the Au and Co(OH) sub(2) showed only 0.9 and 13 mA cm super(-2), respectively. The enhanced conductivity of the Co(OH) sub(2)/Au matrix due to the presence of Au, as well as the combined catalytic activity, seemed to be responsible for the superior performance of the Co(OH) sub(2)/Au-composite electrodes.