Improved Electrocatalytic Performance of Core-shell NiCo/NiCoOx with amorphous FeOOH for Oxygen-evolution Reaction

• Published in: Electrochimica acta Vol. 257; pp. 1 - 8
• Main Authors: Shao, Yubo, Zheng, Meiyong, Cai, Minmin, He, Lan, Xu, Cailing
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10-12-2017
• Subjects: Electrocatalytic water splitting; FeOOH; Hydrogen-evolution reaction (HER); Hydrogenation; Nickel cobalt oxides; Oxygen-evolution reaction (OER); FeOOH; Nickel cobalt oxides; Hydrogen-evolution reaction (HER); Oxygen-evolution reaction (OER); Electrocatalytic water splitting; Hydrogenation
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2017.09.093

Hierarchical NiCo/NiCoOx with amorphous FeOOH electrocatalysts have been fabricated by a low temperature hydrogenation treatment of Ni/Co bimetallic carbonate hydroxide nanowire arrays on Ni foam and subsequent chemical bath deposition process. The NiCo/NiCoOx composites consisted of NiCo alloy core and nickel cobalt oxide shell with the thickness of around 5nm exhibits excellent electrocatalytic activity for hydrogen-evolution reaction (HER) in 1M KOH due to the enhanced conductivity and the large defect-rich interface. However, the electrocatalytic activity for oxygen-evolution reaction (OER) is boosted by ultrathin, amorphous and interconnected FeOOH nanosheets grown on the hierarchical NiCo/NiCoOx composites because of the promoted conductivity and electron transfer ability of the metallic NiCo core and the suitable interaction of NiCoOx and FeOOH with OH− groups. In oxygen evolution process, a low overpotential of 278mV is required to achieve a current density of 10mAcm−2 for NiCo/NiCoOx@FeOOH samples, and the Tafel slope is only 47.5mVdec−1. When integrated NiCo/NiCoOx with NiCo/NiCoOx@FeOOH in an alkaline electrolyzer, a full water splitting current density of 10mAcm−2 and high electrochemical stability can be obtained at 1.65V.