Heterogeneous lamellar-edged Fe-Ni(OH)2/Ni3S2 nanoarray for efficient and stable seawater oxidation
Heterogeneous lamellar-edged Fe-Ni(OH)2/Ni3S2 nanoarray for efficient and stable seawater oxidation
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异质层状边缘 Fe-Ni(OH)(2)/Ni3S2 纳米阵列用于高效稳定的海水氧化
DOI：
10.1007/s12274-020-3164-3
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发表时间：
2020-11-09
期刊：
影响因子：
9.9
通讯作者：
Hu, Wenbin
中科院分区：
文献类型：
--
作者：
Cui, Baihua;Hu, Zheng;Hu, Wenbin
开发高效的海水电解非贵金属催化剂具有重要意义，但由于析氧反应（OER）动力学缓慢和阳极氯电化学功能受损，因此具有挑战性。本文报道了一种具有二级Fe-Ni(OH)(2)片层边缘的Ni3S2纳米阵列的异质结构，该异质结构暴露了丰富的活性位点，可用于海水氧化。所得Fe-Ni(OH)(2)/Ni3S2纳米阵列在碱性人工海水中直接作为独立阳极电极。它只需要269 mV的过电位就能提供10 mA的电流密度，中心点cm(-2)，塔菲尔斜率低至46 mV中心点dec（-1）。在100 mA中心dot cm（-2）的高电流密度下进行27小时计时电位测定，结果显示其衰减可以忽略不计，表明Fe中心dot Ni(OH)(2)/Ni3S2@NF电极具有良好的稳定性。法拉第析氧效率接近95%，表明该催化剂在盐水中具有良好的选择性。这种理想的催化性能可能得益于Fe活化剂的引入和提供大量活性和选择性位点的异质结构。密度泛函理论（DFT）计算表明，OER在Fe位点上的理论过电位低于Cl-2的演化反应，这与Ni位点相反。实验和理论研究为工业海水电解用高性能铁基电极的合理设计提供了有力支持。
Development of efficient non-precious catalysts for seawater electrolysis is of great significance but challenging due to the sluggish kinetics of oxygen evolution reaction (OER) and the impairment of chlorine electrochemistry at anode. Herein, we report a heterostructure of Ni3S2 nanoarray with secondary Fe-Ni(OH)(2) lamellar edges that exposes abundant active sites towards seawater oxidation. The resultant Fe-Ni(OH)(2)/Ni3S2 nanoarray works directly as a free-standing anodic electrode in alkaline artificial seawater. It only requires an overpotential of 269 mV to afford a current density of 10 mA center dot cm(-2) and the Tafel slope is as low as 46 mV center dot dec(-1). The 27-hour chronopotentiometry operated at high current density of 100 mA center dot cm(-2) shows negligible deterioration, suggesting good stability of the Fe center dot Ni(OH)(2)/Ni3S2@NF electrode. Faraday efficiency for oxygen evolution is up to similar to 95%, revealing decent selectivity of the catalyst in saline water. Such desirable catalytic performance could be benefitted from the introduction of Fe activator and the heterostructure that offers massive active and selective sites. The density functional theory (DFT) calculations indicate that the OER has lower theoretical overpotential than Cl-2 evolution reaction in Fe sites, which is contrary to that of Ni sites. The experimental and theoretical study provides a strong support for the rational design of high-performance Fe-based electrodes for industrial seawater electrolysis.