摘要
目的在酸性柠檬酸钠体系中,研究了柠檬酸钠对Ni-Sn-Mo合金电沉积机理的影响,明确最大电极反应速率和析氢性能最好的合金镀层对应的柠檬酸钠浓度。方法采用循环伏安法、电化学阻抗谱、计时电流法和阴极极化曲线,对不同柠檬酸钠浓度下Ni-Sn-Mo合金电沉积行为及析氢性能进行研究,采用扫描电镜对Ni-Sn-Mo合金的表面形貌进行表征,并用能谱仪检测合金的成分。结果由循环伏安曲线得出Ni-Sn-Mo合金的电沉积是一个不可逆过程,当柠檬酸钠浓度为0.2 mol/L时,合金共沉积还原峰的电位最正(−0.96 V(vs.Ag/Ag^+))。由电化学阻抗谱可知,当柠檬酸钠浓度为0.1 mol/L时,在低频端出现扩散特征;当柠檬酸钠浓度为0.2~0.4 mol/L时,反应不受扩散影响;当柠檬酸钠浓度为0.2 mol/L时,极化电阻(Rp)达到最小值(11718.1Ω·cm^2),电极反应最容易发生。由计时电流曲线可知,随着柠檬酸钠浓度的增大,Ni-Sn-Mo合金晶核形成始终遵循连续成核规律。由SEM和EDS分析表明,随着柠檬酸钠浓度增大,Ni-Sn-Mo合金的晶粒尺寸先减小后增大;随着合金中Sn含量增加,合金的晶粒由胞状转变为不规则形状。由阴极极化曲线和电化学阻抗谱可知,当柠檬酸钠浓度为0.1 mol/L时,析氢电位(−1.05 V)最正,电荷转移电阻(4.906W·cm^2)最小,析氢性能最好,从能量因素和几何因素上都改善了合金的析氢性能。结论当柠檬酸钠浓度为0.2 mol/L时,还原峰电位最正,电极反应最容易发生。在Ni-Mo合金镀层中添加Sn,增加了镀层的比表面积,并且提高了电子传输速率,有利于析氢性能的提高。
The work aims to study the effect of sodium citrate on the electrodeposition mechanism of Ni-Sn-Mo alloy in an acidic sodium citrate system,and to find out the maximum electrode reaction rate and the corresponding sodium citrate concentration of the alloy coating with the best hydrogen evolution performance.The electrodeposition mechanism and hydrogen evolution behavior of Ni-Sn-Mo alloy with different sodium citrate concentration were studied by cyclic voltammetry curve,electrochemical impedance spectroscopy,chronoamperometry and cathodic polarization curve.The surface morphology of Ni-Sn-Mo alloy was characterized by scanning electron microscopy and its composition was detected by energy spectrometer.The electrodeposition of Ni-Sn-Mo alloy obtained by cyclic voltammetry curve was an irreversible process.When the corresponding sodium citrate concentration was 0.2 mol/L,the potential of the alloy co-deposition reduction peak was the most positive(−0.96 V(vs.Ag/Ag^+)).According to the electrochemical impedance spectroscopy,when the concentration of sodium citrate was 0.1 mol/L,diffusion characteristics appeared at the low frequency end,and when sodium citrate concentration was 0.2~0.4 mol/L,the reaction was not affected by diffusion.When the concentration of sodium citrate was 0.2 mol/L,the polarization resistance(Rp)reached the minimum value(11718.1Ω·cm^2)and electrode reaction was most likely to happen.Through CA curves,the crystal nucleation of Ni-Sn-Mo alloy always followed the rule of continuous nucleation as the concentration of sodium citrate increased.SEM and EDS results showed that the grain of Ni-Sn-Mo alloy decreased and then increased with increase of sodium citrate concentration.With the increase of Sn content in the alloy,the grain of the alloy changed from cellular to irregular shape.According to the cathodic polarization curve and electrochemical impedance spectrum,when the concentration of sodium citrate was 0.1 mol/L,the hydrogen evolution potential(−1.05 V)was the most positive,the charge transfer resistance(4.906Ω·cm^2)was the smallest,and the hydrogen evolution performance was the best,which improved the hydrogen evolution performance of the alloy from the aspects of energy and geometry.When the concentration of sodium citrate is 0.2 mol/L,the reduction peak potential is the most positive and the electrode reaction is most likely to happen.Adding Sn to Ni-Mo alloy coating increases the specific surface area of coating and improves the electron transfer rate,which is conducive to the improvement of hydrogen evolution performance.
作者
张丽楠
温林洁
周宗熠
崔鹏飞
李运刚
杨海丽
ZHANG Li-nan;WEN Lin-jie;ZHOU Zong-yi;CUI Peng-fei;LI Yun-gang;YANG Hai-li(Key Laboratory of the Ministry of Education for Modern Metallurgy Technology,North China University of Science and Technology,Tangshan 063210,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2020年第9期182-190,共9页
Surface Technology
基金
国家自然科学基金(51774142)
关键词
Ni-Sn-Mo合金
柠檬酸钠
电沉积
成核机理
析氢行为
Ni-Sn-Mo alloy
sodium citrate
electrodeposition
nucleation mechanism
hydrogen evolution behavior
