电沉积制备Cu-Ni-Mo三元电极及其析氢性能

Preparation of Cu-Ni-Mo Ternary Electrode by Electrodeposition and Its Hydrogen Evolution Performance

目的制备一种在碱性溶液中具有高效、低成本等优点的铜基析氢阴极材料。方法在35℃下采用直流电沉积法,在泡沫镍(NF)表面分别沉积Cu-Ni、Cu-Ni-Mo镀层,制备Cu-Ni/NF、Cu-Ni-Mo/NF析氢电极。利用X射线衍射分析仪(XRD)、扫描电镜(SEM)和能谱仪(EDS)表征电极的表面形貌、结构元素含量及物相。通过电化学阻抗技术(EIS)、线性扫描伏安法(LSV)、循环伏安法(CV)测定电极的析氢性能和催化活性。结果经Mo掺杂后,Mo在Cu-Ni-Mo三元合金中以置换型固溶体的形式存在,与二元镀层相比,增大了镀层的晶格常数。Cu-Ni-Mo/NF三元电极在电流密度10 mV/cm^(2)下,过电位仅为116 mV,塔费尔斜率为104 mV/dec,电荷转移电阻为15.34Ω,电化学活性比表面积(ECSA)为22.33,相较于Cu-Ni/NF二元电极,分别降低了68 mV、27 mV/dec、15.48Ω,ECSA值提高了7.95,且循环稳定性较好。结论引入第3种元素Mo,改变了Cu-Ni二元电极的镀层形貌,使晶粒细化,表现为微粒紧密堆积而成的球胞状结构,从而提升了电极材料的比表面积,为析氢反应提供了更多的活性位点,有助于提高析氢反应效率。由于三金属间的协同作用,与Cu-Ni二元电极相比,Cu-Ni-Mo三元电极显示出更优异的析氢催化性能。

One step DC electrodeposition double-sided plating is an electrodeposition method that can obtain double-sided coated electrodes.The work aims to prepare a porous hydrogen evolution cathode material with high hydrogen desorption activity and stability.Nickel molybdenum binary alloy has good hydrogen evolution performance because of its"synergistic effect",but it also has the problem of component dissolution in the electrolysis process.The formation of Cu-Ni bimetallic catalyst has strong synergistic effect,and its ability to destroy O-H bond is strong,which is conducive to the electrocatalytic process of HER in alkaline solution.By combining the advantages of the two binary alloys,the hydrogen evolution performance of the electrode is improved.This study introduced the preparation of a nickel based hydrogen evolution cathode material with high efficiency,low cost and high stability in alkaline solution.The experiment was conducted at 35℃through the three-electrode system with two anode plates(graphite)and with the foam nickel as the cathode.The two anode plates were on the left and right sides of the foam nickel,and the area was slightly larger than that of the foam nickel.Cu-Ni and Cu-Ni-Mo coatings were deposited on the surface of foam nickel(NF)by one-step DC electrodeposition Cu-Ni/NF Binary hydrogen evolution electrode,Cu-Ni-Mo/NF Ternary hydrogen evolution electrode.The surface morphology,content of structural elements and phase of the electrode were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The hydrogen evolution performance and catalytic activity of the electrode were characterized by electrochemical impedance spectroscopy(EIS),linear sweep voltammetry(LSV)and cyclic voltammetry(CV).The test results showed that compared with the binary coating,Mo doping existed in the form of displacement solid solution in the alloy structure,which increased the lattice constant of the coating.In terms of the electrochemical performance of Cu-Ni-Mo/NF,at a current density of 10 mV/cm^(2),the over potential of the ternary electrode was only 116 mV,the Tafel slope was 104 mV/dec,the charge transfer resistance was 15.34Ω,and the electrochemical active specific surface area(ECSA)was 22.33.Compared with Cu-Ni/NF,the binary electrode decreased by 68 mV,27 mV/dec,15.48Ω,and the ECSA value increased by 7.95.After 2000 cycles of CV cycle,the hydrogen evolution overpotential changed little,showing good hydrogen evolution stability.Analysis of the test results can be found that when the third element Mo is introduced,the coating morphology of the Cu-Ni binary electrode is changed,the grains are refined,and the spherical cell structure formed by the close accumulation of particles,so as to improve the specific surface area of the electrode material,provide more active sites for hydrogen evolution reaction,and help to improve the efficiency of hydrogen evolution reaction.Due to the synergistic effect between the three metals,Cu-Ni-Mo ternary electrode shows better HER catalytic performance than Cu-Ni binary electrode.Therefore,Cu-Ni-Mo ternary electrode is a good HER electrocatalyst.In the process of production and preparation,it does not produce adverse by-products to environmental protection,and can be produced in batch,which is of great significance to its promotion and market application.