IrNi nanoparticle-decorated flower-shaped NiCo₂O₄ nanostructures: controllable synthesis and enhanced electrochemical activity for oxygen evolution reaction

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• 作者：Zhifan Chen 陈志范 ; Hongbin Zhao 赵宏滨 ; Jiujun Zhang 张久俊…
• 关键词：electrocatalysis ; OER ; bimetal
• 刊名：Science China Materials
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：60
• 期：2
• 页码：119-130
• 全文大小：4374KB
• 刊物类别：Materials Science, general; Chemistry/Food Science, general;
• 刊物主题：Materials Science, general; Chemistry/Food Science, general;
• 出版者：Science China Press
• ISSN：2199-4501
• 卷排序：60

文摘

In this work, we demonstrated the enhanced oxygen evolution reaction (OER) activity of flower-shaped cobalt-nickel oxide (NiCo₂O₄) decorated with iridium-nickel bimetal as an electrode material. The samples were prepared by carefully depositing pre-synthesized IrNi nanoparticles on the surfaces of the NiCo₂O₄ nano-flowers. Compared with bare NiCo₂O₄, IrNi, and IrNi/Co₃O₄, the IrNi/NiCo₂O₄ exhibited significantly enhanced electrocatalytic activity in the OER, including a lower overpotential of 210 mV and a higher current density at an overpotential of 540 mV. We found that the IrNi/NiCo₂O₄ showed more efficient electron transport behavior and reduced polarization because of its bimetal IrNi modification by analyzing its Tafel slope and turnover frequency. Furthermore, the electrocatalytic mechanism of IrNi/NiCo₂O₄ in the OER was studied, and it was found that the combined active sites of the composite effectively improved the rate determining step. The synergic effect of the bimetal and metal oxide plays an important role in this reaction, enhancing the transmission efficiency of electrons and providing more active sites for the OER. The results reveal that IrNi/NiCo₂O₄ is an excellent electrocatalyst for OER.