Coupling a titanium dioxide based heterostructure photoanode with electroless-deposited nickel-phosphorus alloy coating on magnesium alloy for enhanced corrosion protection
Coupling a titanium dioxide based heterostructure photoanode with electroless-deposited nickel-phosphorus alloy coating on magnesium alloy for enhanced corrosion protection
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DOI：
10.1016/j.jmst.2022.02.049
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发表时间：
2022-04
期刊：
影响因子：
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通讯作者：
Yue Liu;Feng Peng;Guangwei Yang;Z. Xie;W. Dai;Y. Ouyang;Liang Wu;C. Zhong
中科院分区：
文献类型：
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作者：
Yue Liu;Feng Peng;Guangwei Yang;Z. Xie;W. Dai;Y. Ouyang;Liang Wu;C. Zhong
利用光电化学阴极保护（PECCP）通过引入金属镍中间层，可以对自腐蚀电位较低的金属进行间接腐蚀保护。然而，由于半导体的固有特性，提高 PECCP 效率的能力仍然具有挑战性。在此，通过将共价有机框架（TpBD）装饰的TiO2光阳极（TiO2/TpBD）与镁合金上的镍涂层耦合来证明这种能力，以实现有效的腐蚀保护。复合光阳极表现出对镍夹层的直接PECCP和对镁合金的间接腐蚀保护。通过场发射扫描电子显微镜（FESEM）、透射电子显微镜（TEM）和X射线光电子能谱（XPS）证实了纳米管阵列和光电阳极共价有机骨架的复合结构。电化学和光电化学测量结果（包括莫特-肖特基曲线、光致电位变化和电化学阻抗谱（EIS））证明了镀镍镁合金增强的光电化学转换能力和PECCP性能。最后，提出了一种腐蚀保护机制，其中增强的 PECCP 效率归因于直接 Z 型异质结的形成，价带 (VB) XPS 和电子自旋共振表征的结果证实了这一点。
The utilization of photoelectrochemical cathodic protection (PECCP) enables an indirect corrosion protection of metals with low self-corrosion potential by introducing a metallic nickel interlayer. However, the ability to enhance the PECCP efficiency remains challenging because of the inherent property of the semiconductor. Herein, this ability is demonstrated by coupling a covalent organic framework (TpBD) decorated TiO2photoanode (TiO2/TpBD) with nickel coating on magnesium alloy for an effective corrosion protection. The composite photoanode showed direct PECCP for the nickel interlayer and indirect corrosion protection of the magnesium alloy. The composite structure of the nanotube array and the covalent organic framework for the photoanode were confirmed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The enhanced photoelectrochemical conversion capability and PECCP performance of the nickel-coated Mg alloy were evidenced by the results from electrochemical and photoelectrochemical measurements including Mott-Schottky curves, photoinduced potential variations, and electrochemical impedance spectroscopy (EIS). Lastly, a corrosion protection mechanism is proposed, where the enhanced PECCP efficiency is attributed to the formation of a direct Z-scheme heterojunction, which is substantiated by the results from valence band (VB) XPS and electron spin resonance characterizations.