物理化学学报 >> 2016, Vol. 32 >> Issue (11): 2745-2752.doi: 10.3866/PKU.WHXB201608083

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原位生长Pd/Ni(OH)2/NF复合催化剂及其析氢性能

吴昱,罗键*()   

  • 收稿日期:2016-07-06 发布日期:2016-11-08
  • 通讯作者: 罗键 E-mail:agsun2003@163.com
  • 基金资助:
    国家自然科学基金(51272297)

In situ Growth of a Pd/Ni(OH)2/NF Composite Catalyst for the Hydrogen Evolution Reaction

Yu WU,Jian LUO*()   

  • Received:2016-07-06 Published:2016-11-08
  • Contact: Jian LUO E-mail:agsun2003@163.com
  • Supported by:
    the National Natural Science Foundation of China(51272297)

摘要:

采用水热合成法在泡沫镍上原位构建了低贵金属含量的钯/氢氧化镍纳米复合催化剂(Pd/Ni(OH)2/NF)。通过扫描电镜,能谱仪,X射线衍射仪和X射线光电子谱仪等分析技术表征了催化剂的形貌和微观结构;运用线性扫描伏安法,电化学阻抗谱和计时电流法等手段研究了催化剂的催化析氢性能。实验结果显示复合催化剂具有特殊的微观构型,超薄的Ni(OH)2薄片生长在泡沫镍表面,纳米尺寸的钯均匀地镶嵌在氢氧化镍薄片中。催化剂表面的氢氧化镍有利于促进水的解离,加快氢中间体的形成;均匀分散的钯极易吸附解离的氢中间体,快速地复合成氢气分子。我们发现复合催化剂能协同加快析氢反应过程,极大地降低析氢过电位,提高了析氢活性。此外,复合催化剂原位生长在泡沫镍上,有效地提高了催化电极的稳定性。

关键词: 双功能体系, 析氢反应, 电解水, 复合催化剂, 氢氧化镍

Abstract:

We devised and fabricated a Pd/Ni(OH)2 composite catalyst with low noble metal content that grows in situ on nickel foam (NF) using the hydrothermal synthesis method. The morphology and microstructure of the catalyst were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The hydrogen evolution performance of the composite catalyst was evaluated by linear scanning voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CP). The composite catalyst exhibited a special nanostructure consisting of an ultra-thin Ni(OH)2 film growth on the surface of the nickel foam with palladium nanoparticles uniformly embedded in the Ni(OH)2 thin film. The Ni(OH)2 on the surface of the catalyst might considerably promote the dissociation of water and the formation of hydrogen intermediates (Had) that subsequently adsorbed on the nearby Pd and quickly recombined into hydrogen molecules. The composite catalyst exhibits a synergistic effect for the hydrogen evolution reaction (HER), which might decrease the over-potential of hydrogen evolution and enhance the activity of the hydrogen evolution reaction. Growing the composite catalyst in situ on the nickel foam effectively improved the stability of the catalyst for the HER in alkaline solutions.

Key words: Difunctional system, Hydrogen evolution reaction, Electrolysis of water, Composite catalyst, Nickel hydroxide

MSC2000: 

  • O646