Concurrent Deposition and Exfoliation of Nickel Hydroxide Nanoflakes Using Liquid Crystal Template and Their Activity for Urea Electrooxidation in Alkaline Medium
Arunachalam, M. A. Ghanem, A. M. Al-Mayouf, J. P. Singh, P. . 2017
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 450m2 g−1 surface areawhich 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.
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…