电沉积制备泡沫镍/镍–硫–二氧化钛复合电极及其析氢催化活性

Preparation of nickel foam/nickel–sulfur–titania composite electrode by electrodeposition and its catalytic activity for hydrogen evolution

以泡沫镍为基体,利用电沉积法制备Ni–S–TiO_2多孔复合电极,镀液组成和工艺条件为:NiSO_4·6H_2O 180~250 g/L,H_3BO_3 35~40 g/L,硫脲100~150 g/L,TiO_2纳米微粒(粒径约为20 nm)5~20 g/L,表面活性剂0.1 g/L,pH 3.5~4.0,温度45°C,电流密度30 mA/cm^2,机械搅拌速率250~300 r/min,时间30 min。研究了镀液中TiO_2添加量对复合电极析氢活性的影响。采用扫描电镜和X射线衍射仪表征了Ni–S–TiO_2复合电极的表面形貌和晶态结构。利用阴极极化曲线和电化学阻抗谱测试研究不同电极在1 mol/L NaOH溶液中的析氢催化活性,并通过计时电位法研究电极的稳定性。结果表明,Ni–S–TiO_2电极由纳米TiO_2粒子相和非晶态Ni–S相构成,其析氢催化活性和稳定性优于Ni–S电极。

A porous Ni-S-TiO2 composite electrode was prepared with nickel 1barn as substrate by electrodeposmon. Tne bath composition and process conditions are： NiSO4 6H20 180-250 g/L, H3BO3 35-40 g/L, thiourea 100-150 g/L, TiO2 nanoparticles with a size of ca.20 nm 5-20 g/L, surfactant 0.1 g/L, pH 3.5-4.0, temperature 45 ℃, current density 30 mA/cm2, mechanical stirring rate 250-300 r/min, and time 30 rain. The effect of titania dosage in plating bath on catalytic activity of hydrogen evolution at the composite electrode was studied. The surface morphology and crystal structure of the composite electrode were characterized by scanning electronic microscopy and X-ray diffractometry, respectively. The catalytic activity of hydrogen evolution at different electrodes in 1 mol/L NaOH solution were studied by cathodic polarization measurement and electrochemical impendence spectroscopy, and the stability of the electrodes were examined by chronopotentiometry. The results showed that the obtained Ni-S-TiO2 electrode is composed of TiO2 particle phase and Ni-S amorphous phase, and has better catalytic activity for hydrogen evolution than the Ni-S electrode.