Ni-Cr-Mo-Cu多孔磷化物电极的制备及电催化析氢性能研究

Research on the preparation and electrocatalytic hydrogen evolution performance of porous Ni-Cr-Mo-Cu phosphating electrode

摘要:

为了解决电解水析氢过程中所用电极材料的低效率、高成本问题，采用粉末冶金法—低温磷化法制备了一种Ni-Cr-Mo-Cu多孔磷化物电极。采用X射线衍射分析(XRD)、场发射电镜(SEM)、X射线能谱分析(EDS)等对电极的物相、形貌结构以及元素分布等进行表征；通过开路电位、线性极化、交流阻抗等方法测试了磷化物电极材料的电催化析氢性能。结果表明Ni-Cr-Mo-，Cu多孔磷化物电极具有优异的析氢性能，调节磷化时间可在较大程度上提高其析氢催化活性。在室温条件下，磷化时间为2小时的Ni-Cr-Mo-Cu多孔磷化物电极在6mol/L KOH的溶液中析氢性能较好，其析氢过电位仅有-0.19V (vs RHE)，交换电流密度为10mA/cm2时对应的极化电位为-0.20V (vs RHE)；经开路电位测试18000s后，电极材料的开路电位 (η) 从+0.80变化为0.78V (vs RHE)，仅降低0.02 V，表明其具有良好的电催化稳定性。

Abstract:

In order to solve the low efficiency and high cost of electrode materials used in the process of electrolytic water hydrogen evolution, porous Ni-Cr-Mo-Cu phosphating electrode was prepared by powder metallurgy and low temperature phosphating method. The phase, morphologic structure and element distribution of the electrode were characterized by X-ray diffraction analysis (XRD), field emission electron microscope (SEM) and X-ray energy spectrum analysis (EDS). The electrocatalytic hydrogen evolution properties of phosphor electrode materials were tested by open-circuit potential, linear polarization and ac impedance. The results showed that the porous Ni-Cr-Mo-Cu phosphating electrode exhibited excellent hydrogen evolution performance and its catalytic activity can be improved to a great extent by adjusting the phosphating time. At room temperature, the porous Ni-Cr-Mo-Cu phosphating electrode with a phosphating time of 2 hours has a good hydrogen evolution performance in a solution of 6mol/L KOH, and its hydrogen evolution overpotential is only -0.19V (vs RHE). When the exchange current density is 10 mA/cm2, the corresponding polarization potential is -0.20V (vs RHE). After 18000s, the open-circuit potential (OCP) of the electrode material changed from +0.80 to 0.78V (vs RHE), which decreased only 0.02 V, indicating that the electrode material had good electro-catalytic stability.