Influence of a MnO2-WC interlayer on the stability and electrocatalytic activity of titanium-based PbO2 anodes
Influence of a MnO2-WC interlayer on the stability and electrocatalytic activity of titanium-based PbO2 anodes
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DOI：
10.1016/j.electacta.2019.135381
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发表时间：
2020-01
影响因子：
6.6
通讯作者：
Changbin Tang;Lu Yuxuan;Wang Fei;N. Hao;Lihua Yu;J. Xue
中科院分区：
文献类型：
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作者：
Changbin Tang;Lu Yuxuan;Wang Fei;N. Hao;Lihua Yu;J. Xue
为了克服钛基PbO 2涂层阳极在电化学氧化处理难降解有机废水中稳定性差的缺点，在MnSO 4溶液中，以碳化钨（WC）颗粒为中间体，通过阳极共沉积的方法制备了一种新型PbO 2涂层阳极（Ti/MnO 2-WC/β-PbO 2）。采用扫描电子显微镜、能量色散X射线、X射线衍射和X射线光电子能谱等表征手段分析了涂层阳极的微观结构和化学组成，包括层间涂层和表面涂层。利用线性扫描伏安法、循环伏安法和电化学阻抗谱分析了中间层和阳极表面的电化学和电催化性能。同时，通过加速寿命试验和对试验样品的综合失效分析，确定了MnO 2-WC复合中间层涂层阳极的失效机理，以及引入复合中间层后的延寿机理。结果表明，与MnO 2相比，MnO 2-WC中间层的导电性得到了很大的提高，具有更高的析氧电位和更好的电催化活性。在MnO 2-WC中间层表面阳极沉积的β-PbO 2晶粒变得更加细小、致密和均匀。MnO 2-WC复合中间层增加了PbO 2表面活性中心的数量，促进了PbO 2表面涂层的电结晶过程，从而使PbO 2涂层变厚。结果表明，Ti/MnO 2-WC/β-PbO 2涂层阳极具有良好的电催化活性和上级稳定性，其加速寿命是Ti/β-PbO 2涂层阳极的2倍以上。
In order to overcome the unsatisfactory stability drawback of titanium-based PbO2-coated anodes used in electrochemical oxidation treatments of refractory organic wastewater, a novel PbO2-coated anode obtained by introducing a tungsten carbide (WC) modified manganese dioxide composite coating (MnO2-WC) via anodic co-deposition in a MnSO4solution mixed with WC particles as an intermediate is fabricated (Ti/MnO2-WC/β-PbO2). Characterization measurements including scanning electronic microscopy accompanied by energy dispersive X-rays, X-ray diffraction, and X-ray photoelectron spectroscopy are used to analyze the microstructure and chemical composition of the coated anode, including the interlayer coating and superficial coating. The electrochemical and electrocatalytic properties of the interlayer and anode surfaces are analyzed using linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. Meanwhile, the failure mechanism of the anode coated with the MnO2-WC composite interlayer, and the life-extension mechanism due to introducing the composited interlayer, are determined via accelerated-life tests and a comprehensive failure analysis of the tested samples. The results show that, compared with MnO2, the conductivity of the MnO2-WC interlayer is greatly improved and exhibits higher oxygen evolution potential as well as better electrocatalytic activity. The anodic β-PbO2grains deposited on the MnO2-WC interlayer surface become finer, more compact and homogeneous. The MnO2-WC composite interlayer increases the number of surface active sites and promotes the electro-crystallization process of the PbO2surface coatings, which results in thicker PbO2coatings. As a result, the Ti/MnO2-WC/β-PbO2-coated anode shows better electrocatalytic activity and superior stability in this work, and its accelerated life is more than twice that of Ti/β-PbO2anodes.