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

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

摘要:

本文研究了在离子液体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表示,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 m₂/s,平均传质系数为0.083。本文用扫描电镜(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,结果显示,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/cm₂时可以得到平整致密的Ir镀层。

Abstract:

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 m₂/s and the average transfer coefficient is 0.083. The morphology and composition of iridium coatings prepared on molybdenum substrates were characterized by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The morphology of iridium coatings was dependent on the potential, time and current density of electrodeposition. Compact coatings were obtained at the reduction peak potential with a balance between the nucleation rate and the growth rate. Flat and compact coatings were formed when current density ranged from 0.5 to 1.82 mA/cm₂ in the galvanostatic electrodeposition.