Concurrent Deposition and Exfoliation of Nickel Hydroxide Nanoflakes Using Liquid Crystal Template and Their Activity for Urea Electrooxidation in Alkaline Medium
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- 作者：Mohamed A. Ghanem ; Abdullah M. Al-Mayouf ; Jai P. Singh…
- 关键词：Nickel hydroxide ; Nanoflakes ; Liquid crystal template ; Electrooxidation ; Urea
- 刊名：Electrocatalysis
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：8
- 期：1
- 页码：16-26
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Electrochemistry; Physical Chemistry; Catalysis; Energy Technology;
- 出版者：Springer US
- ISSN：1868-5994
- 卷排序：8
文摘
Nickel hydroxide nanoflakes (Ni(OH)2-NF) were prepared by chemical deposition and in situ exfoliation of nickel hydroxide layers confined in the aqueous domain of the liquid crystalline hexagonal template of Brij®78 surfactant. Using excess of sodium borohydride as a reducing agent generates concurrent excessive dynamic hydrogen bubbles which exfoliated and fragmented the nickel hydroxide layers precipitated within the soft hexagonal template. The physicochemical characterizations of Ni(OH)2-NF by using surface area analyser, X-ray diffraction (XRD), XPS and transmission electron microscope (TEM) showed the formation of α-Ni(OH)2 nanoflakes with thickness of 2–3 nm and have about 450 m2 g−1 surface area which is 20 times higher than that for bare nickel (bare-Ni) deposited without surfactant template. The electrocatalytic activity of the Ni(OH)2-NF catalyst for urea electrolysis was studied by cyclic voltammetry and chronoamperometry techniques. The Ni(OH)2-NF has shown a superior activity for the electrochemical oxidation of urea in alkaline solution and exhibits more than tenfold increase in activity in comparison with the bare-Ni deposit. The enhancement of urea electrooxidation activity was related to the superficial enhancement in the electroactive surface area of Ni(OH)2-NF. This new approach of deposition and in situ exfoliation by using liquid crystal template and hydrogen bubbles offers a new platform to nanostructuring wide range of catalysts with better catalytic performance.