采用双极性电沉积技术制备了铜基梯度镍电沉积层析氢电极材料,镀液组成和工艺条件为:NiSO4?6H2O 200 g/L, NiCl2?6H2O 40 g/L,H3BO3 40 g/L,pH 4,温度45 °C,驱动电压5 V或11 V,时间5 min.双极性电沉积过程中不同位置的铜/溶液界面过电位不同.所得镍电沉积层的结构和成分均呈梯度变化.电化学噪声测试结果表明,双极性电沉积过程由电化学极化控制,成核过程占主导,提高驱动电压有利于Ni的形核.在驱动电压11 V下制备的梯度镍层在30% NaOH溶液中析氢的塔菲尔斜率为47 mV/dec.铜基梯度镍有效结合了铜的优良导电性能和镍的析氢催化性能,与金属镍和常规电沉积制备的铜基镍电沉积层相比,具有更强的导电性,电解水制氢时的阴极电流损耗变小,从而令析氢效率提高.%A gradient nickel coating was obtained on copper substrate by bipolar electrodeposition and used as a hydrogen evolution electrode. The bath composition and process conditions were as follows: NiSO4?6H2O 200 g/L, NiCl2?6H2O 40 g/L, H3BO3 40 g/L, pH 4, temperature 45 °C, driving voltage 5 V or 11 V, and deposition time 5 min. The structure and composition of the nickel coating varied in gradient. The copper/solution interface overpotentials at different positions were different during the bipolar electrodeposition process. The electrochemical noise test results showed that the bipolar electrodeposition process was controlled by electrochemical polarization, and the nucleation process was dominant. The increase in driving voltage facilitated the nucleation of Ni. The Tafel slope of hydrogen evolution in 30% NaOH solution for the gradient nickel coating obtained at 11 V was 47 mV/dec. The copper-based gradient nickel combines the excellent conductivity of copper and the hydrogen evolution catalytic activity of nickel. Compared with metallic nickel and the copper-based nickel coating prepared by conventional electrodeposition, the copper-based gradient nickel coating has better conductivity and higher hydrogen evolution efficiency for a lower cathodic current loss during water electrolysis.
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