离子液体[BMIM]PF6中铬的电沉积行为简

以一氯丁烷、N-甲基咪唑和KPF6为原料，合成了1-丁基-3-甲基咪唑六氟磷酸盐离子液体(BMIM]PF6)，用红外光谱(IR)对产物进行了结构分析. 用循环伏安法测试该离子液体在85 ℃下的电化学窗口为4.7 V. 考察了BMIM]PF6-Cr(Ⅲ)电解液的电化学行为，结果表明，在85 ℃下Cr(Ⅲ)的还原过程是受扩散控制的一步还原不可逆过程，Cr(Ⅲ)的传递系数α=0.023，阴极扩散系数D0=1.142×10-6 cm2/s. 在85 ℃和-1.5 V条件下，用恒电势法在铜片上电沉积Cr(Ⅲ)，并通过扫描电子显微镜(SEM)观察了铜片上镀层的表面结构，发现该镀层呈颗粒状，且颗粒的体积随沉积时间的延长而增大. X射线能量色散谱(EDS) 和X射线粉末衍射(XRD)测试结果表明，该镀层为无定形的金属铬.

Electrodeposition Behavior of Chromium in Ionic Liquid [BMIM]PF6

1-Butyl-3-methylimidazolium hexafluorophosphate(BMIM]PF6) ionic liquid was synthesized by 1-chlorobutane, N-methylimidazole and KPF6. The structure of ionic liquid was investigated by IR spectrum. The electrochemical window of BMIM]PF6 was determined to be 4.7 V at 85 ℃ by cyclic voltammetry. The electrochemical behavior of theBMIM]PF6-Cr(Ⅲ) electrolyte was studied. The reduction of chromium from Cr(Ⅲ) to Cr(0) in the solution is a one-step irreversible growth process which is controlled by diffusion. The cathodal transfer coefficient(α) is 0.023 and the cathode diffusion coefficient(D0) is 1.142×10-6 cm2/s. The electrodeposition of chromium on copper substrate from BMIM]PF6-Cr(Ⅲ) were experimented by potentiostatic method at -1.5 V. The surface morphology of chromium coating was characterized by means of scanning electron microscopy(SEM) and its morphology was granular structure. The size of granulae increase with the increase of deposition time. The chemical composition and structure of chromium coating were tested by energy dispersive spectrometry(EDS) and X-ray diffraction(XRD). The results indicate that the coating consist of amorphous metallic chromium.