High performance nano-Ni/Graphite electrode for electro-oxidation in direct alkaline ethanol fuel cells

By Soliman, Ahmed B.; Abdel-Samad, Hesham S.; Rehim, Sayed S. Abdel; Ahmed, Mohamed A.; Hassan, Hamdy H.
Published in Journal of Power Sources NULL 2016

Abstract

Abstract Ni/Graphite electrocatalysts (Ni/G) are successfully prepared through electrodeposition of Ni from acidic (pH = 0.8) and feebly acidic (pH = 5.5) aqueous Ni (II) baths. The efficiencies of such electrodes are investigated as anodes for direct alkaline ethanol fuel cells through their ethanol electrooxidation cyclic voltammetric (CV) response in alkaline medium. A direct proportionality between the amount of the electrodeposited Ni and its {CV} response is found. The amounts of the deposited Ni from the two baths are recorded using the Electrochemical Quartz Crystal Microbalance (eQCM). The Ni/G electrodes prepared from the feebly acidic bath show a higher electrocatalytic response than those prepared from the acidic bath. Surface morphology of the Ni particles electrodeposited from feebly acidic bath appears in a nano-scale dimension. Various electrochemical experiments are conducted to confirm that the Ni/G ethanol electrooxidation {CV} response greatly depends on the pH rather than nickel ion concentration of the deposition bath. The eQCM technique is used to detect the crystalline phases of nickel as ?-Ni(OH)2/?-NiOOH and ?-Ni(OH)2/?-NiOOH and their in-situ inter-transformations during the potentiodynamic polarization.

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