离子液体[BDMIM]PF_6修饰碳糊电极的制备及其电化学性能

Preparation and Electrochemical Characteristics of Ionic Liquid 1,2-Dimethyl-3-Butylimidazolium Hexafluorophosphate Modified Carbon Paste Electrode

以离子液体1,2-二甲基-3-丁基咪唑六氟磷酸盐([BDMIM]PF6)代替传统液态石蜡为粘合剂与石墨粉相混合,制备了一种新型的离子液体修饰碳糊电极(IL/CPE)。采用扫描电子显微镜分别对其表面形貌和石蜡碳糊电极(CPE)表面形貌进行了表征。以亚铁氰化钾为电化学探针对IL/CPE的电化学行为进行了研究,并与CPE进行了比较。结果表明,[BDMIM]PF6由于具有较高的导电性,使IL/CPE比CPE具有更高的导电效率,铁氰化钾在电极上的可逆性变好,ΔEP值变小,峰电流响应增加10倍,电极过程由CPE上的吸附控制变为扩散控制,根据计时库仑法求解出铁氰化钾的扩散系数为5.52×10-6cm2/s(25℃)。电化学交流阻抗图亦表明与不导电的液态石蜡油相比,离子液体的存在加快了电子传递。

A new kind of ionic liquid modified carbon paste electrode IL/CPE was constructed based on the substitute of paraffin with 1,2-dimethyl-3-butylimidazolium hexafluorophosphate（[BDMIM]PF6） to mix with graphite powder.The surface morphologies of the IL/CPE were scanned by SEM.The electrochemical behaviors of the IL/CPE were investigated by using K4[Fe（CN）6] as the probe and compared with carbon paste electrode CPE.The results showed that the electrochemical response of K4[Fe（CN）6] was improved with the decreased of ΔEp and 10 times increase of peak currents,which was due to the high conductivity of [BDMIM]PF6.The electrode process was changed from adsorption control to diffusion control.The diffusion coefficient of K4[Fe（CN）6] was calculated by chronocoulometry to be 5.52×10^-6cm2/s at 25℃.The results of electrochemical impedance spectra of IL/CPE also showed that the transfer of electron was faster than that of CPE.