电沉积Ni-S-Co/ZrO2复合电极及其催化析氢性能

Electrodeposition of Ni-S-Co/ZrO2 composite electrode and its high HER activity in alkaline solution

摘要:

在镀液中悬浮粒径约为200~400 nm 的ZrO2固体颗粒，以电沉积方法制备了Ni-S-Co/ZrO2复合电极。XRD和SEM测试结果表明，沉积层由非晶态的Ni、Co、S和单斜晶型的ZrO2粒子组成。镀层表面呈团粒状结构，无裂隙，与基体结合牢固。电化学测试结果表明，25 ℃时，Ni-S-Co/ZrO2复合电极在28％NaOH溶液中，在电流密度100 mA•cm-2下的超电势为145 mV，与未复合纳米ZrO2粒子的Ni-S-Co电极相比降低了50 mV。表明超细ZrO2的掺入有效提高了电极对析氢反应的催化效果。实验表明，沉积的最佳电流密度为70 mA•cm-2，最适宜的ZrO2用量为15 g/L，采用Ni-S-Co作为过渡层可以显著改善复合镀层与基体的结合。

Abstract:

A novel Ni-S-Co/ZrO2 composite electrode was prepared by electrodeposition with ZrO2 particles of 200 nm ~ 400 nm in diameter dispersed in the bath. The XRD result suggests that the Ni-S-Co/ZrO2 coating is composed of amorphous Ni , Co , S and crystalline monoclinic ZrO2 particle. The SEM images show that the coating is composed of granules with porous surface and ca. 50 m in diameter, providing high specific area. The coating is homogeneous and tightly combines with the Ni substrate with a Ni-S-Co interconnecting layer. Electrochemical tests show that the overpotential for hydrogen evolution reaction (HER) of the Ni-S-Co/ZrO2 composite electrode is 145 mV at a current density of 100 mA•cm-2 in 28% KOH solution at 25℃, which is 50 mV lower than that of the Ni-S-Co electrode. The incorporation of ultrafine ZrO2 particle into the Ni-S-Co alloy coating effectively improves the electrocatalytic activity of the Ni-S-Co electrode for hydrogen evolution reaction. The optimal conditions for electrodeposition of the Ni-S-Co/ZrO2 composite electrode are studied as well.