Self-assembly of cobalt hexacyanoferrate crystals in 1-D array using ion exchange transformation route for enhanced electrocatalytic oxidation of alkaline and neutral water

Hoa Thi Bui, Do Young Ahn, Nabeen K. Shrestha, Myung M. Sung, Joong Kee Lee, Sung Hwan Han

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The present study reports a facile synthetic route for thin film formation of a self-standing 1-D structured array of cobalt hexacyanoferrate crystals using an aqueous solution based ion exchange transformation approach. For this, the cobalt hydroxycarbonate 1-D structured array film was used as a sacrificial precursor template for the ion exchange reaction in aqueous K3[Fe(CN)6] solution. By controlling the reaction, 1-D structured array film, or particulate structured film of the cobalt hexacyanoferrate crystals could be obtained, which thus offered possibilities on morphology-dependent property engineering. The films before and after the ion exchange reaction were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry, energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). Further, electrochemical study of the films was performed using voltammetry, and electrochemical impedance spectroscopy. The study reveals the morphology-dependent electrocatalytic property of the cobalt hexacyanoferrate crystal film on water-oxidation. The 1-D structured array film of the cobalt hexacyanoferrate crystals has demonstrated superior electrocatalytic performance on water-oxidation from alkaline and neutral electrolytes, which is competitive to the catalytic performance demonstrated by many outstanding water-oxidation catalysts.

Original languageEnglish
Pages (from-to)9781-9788
Number of pages8
JournalJournal of Materials Chemistry A
Issue number25
StatePublished - 2016 Jan 1


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