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以1-乙基-3-甲基咪唑四氟硼酸盐(EMIMBF_4)为溶剂,乙二醇(EG)为添加剂,考察不同体积比例EMIMBF_4-EG体系对LaCl_3的溶解度影响,用循环伏安法考察La(III)在EMIMBF_4-EG-LaCl_3体系中的电化学行为,最后用扫描电镜(SEM)和能谱仪(EDS)分析了所得金属镧的形貌和成分。研究表明:随着EMIMBF_4-EG体系中EG体积比例从1∶2增大到3∶1,EMIMBF_4-EG体系对LaCl_3溶解度递增,至体积比EG∶EMIMBF_4=3∶1时,体系中LaCl_3浓度高达105 g·L~(-1)。然而,随着EG比例的增加,EMIMBF_4-EG体系稳定性逐渐变差;EMIMBF_4-EG离子液体体系中镧的电沉积行为是一步完成的不可逆过程,经计算,其平均传质系数为0.1079,扩散系数D为1.71×10~(-6)cm2·s~(-1);随着沉积电位的增大,基体Pt层表面电流密度增大,镧沉积物逐渐细化,形貌从颗粒物转变为镀层;在优化的实验条件即温度50℃、转速600 r·min~(-1)、沉积电位-1.7 V,在EMIMBF_4-EG-LaCl_3体系中恒电位电沉积1 h后得到表面平滑、颗粒细密的镀层,镧的成分比例大于98%(质量分数)。
The solubility of LaCl_3 in different volume fractions of EMIMBF_4-EG was investigated by using 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF_4) as solvent and EG as additive. The cyclic voltammetry The electrochemical behavior of La (III) in EMIMBF_4-EG-LaCl_3 system was investigated. The morphology and composition of the resulting lanthanum metal were analyzed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results showed that the solubility of LaCl_3 in EMIMBF_4-EG system increased with the increase of EG volume ratio from 1: 2 to 3:1 in EMIMBF_4-EG system. When the volume ratio of EG: EMIMBF_4 = 3:1, the concentration of LaCl_3 in EMIMBF_4- 105 g · L -1. However, the stability of EMIMBF_4-EG system became worse with the increase of EG ratio. The electrodeposition behavior of lanthanum in EMIMBF_4-EG ionic liquid system was a one-step irreversible process. The calculated average mass transfer coefficient was 0.1079, The coefficient D is 1.71 × 10 -6 cm2 · s -1. With the increase of deposition potential, the surface current density of the Pt layer increases, the lanthanum deposits gradually refine, the morphology changes from the particles to Under the optimal conditions of 50 ℃, 600 r · min -1 and deposition potential -1.7 V, the surface of the coating was smoothed and the surface of the coating was smoothed by EMT in EMIMBF 4-EG-LaCl 3 system Of the coating, lanthanum component ratio greater than 98% (mass fraction).