多孔Ni、Ni-Mo合金及其氧化物的制备与析氢性能

采用快速凝固结合脱合金化的方法制备了纳米多孔Ni、Ni-Mo合金及其氧化物电极材料,通过XRD、SEM、TEM、BET等对电极的物相、形貌结构、孔径分布进行表征,通过线性扫描伏安法、Tafel斜率和计时电位等方法测试多孔电极的电催化析氢性能。结果显示,制备的电极材料在10 mA·cm-2电流密度下Ni-Mo合金析氢活性最强,析氢过程由Volmer-Heyrovsky步骤控制,其表观交换电流密度为0.25 mA·cm-2,经10 000 s恒电流密度(100 mA·cm-2)电解后析氢过电位(η)仅增加39 mV,表现出优良的析氢稳定性。Ni-Mo合金电极比表面积的提高和本征催化活性的改善使其获得了更低的析氢过电位。

Preparation and Hydrogen Evolution Properties of Nanoporous Ni, Ni-Mo Alloys and Their Oxides

Nano porous Ni, Ni-Mo and their oxides electrode materials were prepared by rapid solidification and de-alloying. The phase, morphology and pore size distribution of porous electrode materials were characterized by XRD, SEM, TEM and N₂ absorption-desorption test, and the electro-catalytic hydrogen evolution of porous electrode was tested by linear scanning voltammetry, Tafel slope and chronopotentiometry. The results show that the hydrogen evolution activity of Ni-Mo alloy was the strongest and the process of hydrogen evolution is controlled by Volmer-Heyrovsky step. Its apparent exchange current density (j₀) was 0.25 mA·cm^-2. After electrolyzing 10 000 seconds at constant current density (100 mA·cm^-2), hydrogen evolution over-potential increased only by 39 mV, showing excellent hydrogen evolution stability. The improvement of specific surface area and intrinsic catalytic activity of Ni-Mo alloy electrode resulted in lower hydrogen evolution over-potential.