去合金化法制备多孔镍–硫–钴电极及其催化析氢性能

Electrocatalytic behavior of hydrogen evolution on porous nickel–sulfur–cobalt electrode prepared by dealloying method

采用去合金化法制备了多孔Ni–S–Co(p-Ni–S–Co)合金电极。先依次电沉积制备Ni–S–Co中间层、Ni–S–Co–Zn合金镀层,随后将Ni–S–Co–Zn合金镀层浸泡于50°C的6 mol/L NaOH溶液中8 h以除去镀层中的Zn,即得p-Ni–S–Co合金镀层。表征了多孔镀层的形貌和结构,采用电化学方法着重研究了其催化析氢性能。结果表明,p-Ni–S–Co镀层由带花形纹理的球形颗粒构成,颗粒表面存在大量开放性孔隙,有效增大了镀层的比表面积。p-Ni–S–Co电极在20°C的28%NaOH溶液中时,电流密度为135 mA/cm2下的析氢超电势为108 mV,真实交换电流密度为3.95×10 4mA/cm2,催化析氢性能明显优于普通Ni–S–Co合金电极。

A porous Ni-S-Co （coded as p-Ni-S-Co） alloy electrode was prepared by dealloying method. Firstly, Ni-S-Co intermediate coating and Ni-S-Co-Zn alloy coating were prepared successively. Subsequently Zn in Ni-S-Co-Zn coating was dissolved after immersion in 6 mol/L NaOH solution at 50 ℃ for 8 h, and then p-Ni-S-Co alloy electrode was obtained. The morphology and structure of the porous alloy coating were characterized, and its catalytic performance was studied by electrochemical methods. The results show that the p-Ni-S-Co coating consists of spherical particles with flower-shaped texture, and there are a large amount of open pores on particle surface, which increases the specific surface area of coating. When immersed in 28% NaOH solution at 20 ℃, the hydrogen evolution overpotential on p-Ni-S-Co electrode is 108 mV at a current density of 135 mA/cm2, and its real exchange current density is 3.95 × 10-4 mA/cm2, illustratingthat the catalytic performance of hydrogen evolution is markedly better than that of common Ni-S-Co alloy electrode.