1-丁基-3-甲基咪唑四氟硼酸盐离子液体电沉积制备Ir研究（英文）

Electrodeposition of Iridium in 1-Butyl-3-Methylimidazolium Tetrafluoroborate Ionic Liquid

研究了在离子液体1-丁基-3-甲基咪唑四氟硼酸盐中电沉积制备Ir的电化学行为,在金电极上获得的循环伏安特性曲线显示,Ir(Ⅲ)经过一步还原反应生成Ir,并且该反应是由Ir(Ⅲ)离子的扩散控制的不可逆过程。其中,扩散速率为3.83×10-11 m^2/s,平均传质系数为0.083。用扫描电镜(SEM)、X-射线衍射(XRD)及X-射线光电子能谱(XPS)研究了在钼基体上获得的Ir层的表面形貌及组成,结果表明,Ir层的形貌与沉积电位、时间及电流密度有关。恒电位电沉积过程中,在还原峰电位处由于成核及生长速率达到平衡,可以获得相对致密的镀层。在恒电流电沉积中,当电流密度在0.5~1.82 mA/cm^2时,可以得到平整致密的Ir镀层。

The electrochemical behaviors of iridium electrodeposited in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid were studied. Cyclic voltammograms prepared on the gold electrode suggested that Ir（Ⅲ） was reduced to iridium with an irreversible one-step process, which was controlled by the diffusion of Ir（Ⅲ）. The diffusion rate is 3.83×10^（-11）m^2/s and the average transfer coefficient is 0.083. The morphology of iridium coatings prepared on molybdenum substrates was observed by scanning electron microscopy（SEM）, and the composition was characterized by X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. Results show that the morphologies of iridium coatings is dependent on the potential, the time and the current density of electrodeposition. Compact coatings are obtained at the reduction peak potential with a balance between the nucleation rate and the growth rate. Flat and compact coatings are formed when the current density ranges from 0.5 mA/cm^2 to 1.82 mA/cm^2 in the galvanostatic electrodeposition.