Ni/PdO/RuO_2复合型活性阴极的制备与表征

采用热分解氧化法,在Ni基体上制备以PdO为中间层、RuO2为活性层的Ni/PdO/RuO2复合型活性阴极,并通过XPS、XRD、能量色散X荧光(EDXRF)、SEM、极化曲线、循环伏安法和交流阻抗谱等表征其组成、结构与电化学性能。结果表明,Pd和Ru分别以PdO和RuO2的形式存在于Ni/PdO/RuO2复合型活性阴极中,其含量分别为1.25wt%和1.71wt%;在363K、11mol·L-1NaOH溶液、3kA·m-2电流密度下,Ni/PdO/RuO2复合型活性阴极的析氢过电位比Ni电极和Ni/RuO2电极分别低371和125mV;循环伏安法循环72h后,该复合型活性阴极双电层电容值减小30.6%,比Ni/RuO2电极表层结构更稳定;Ni/PdO/RuO2复合型活性阴极的表面粗糙度大且无明显的裂纹存在,与纯镍电极相比,该复合型活性阴极比表面积增加了31.12倍。

Preparation and Characterization of Ni/PdO/RuO2 Composite Active Cathode for Chlor-Alkali Industry

Ni/PdO/RuO₂ and Ni/RuO₂ composite active cathodes were prepared by thermal decomposition and oxidation method. The composition, structure and electrochemical performance of Ni/PdO/RuO₂ composite active cathode, Ni/RuO₂ active cathode and pure nickel cathode were investigated by XPS, XRD, Energy-dispersive X-Ray Fluorescence spectrometry (EDXRF), SEM, the polarization measurements, cyclic voltammetry and electrochemical impedance spectroscopy. It is found that Pd and Ru elements in the Ni/PdO/RuO₂ composite cathode are mainly in the form of PdO and RuO₂ and these two elements account for 1.25wt% and 1.71wt% respectively. The electrochemical results show that Ni/PdO/RuO₂ composite cathode also exhibits high catalytic activity and stability. At the current density of 3 kA·m^-2, hydrogen evolution overpotential of Ni/PdO/RuO₂ composite active cathode is the lowest, which is about 125 mV lower than Ni/RuO₂ active cathode and 371 mV lower than that of pure nickel in 11 mol·L^-1 NaOH solution at 363 K. For active cathode treated by 72 h voltammetric cycles, the electric double layer capacitance of Ni/PdO/RuO₂ composite active cathode decreases about 30.6%. The roughness of Ni/PdO/RuO₂ composite active cathode is 32.12 times larger than that of the pure nickel cathode. Besides, there is no obvious cracked-mud.