Electrochemical Behavior of Ionic Liquid Confined into Nanopores of Silica Gel Matrix
- 2014年第20卷 
通过溶胶-凝胶法制备了硅胶包载咪唑类离子液体修饰电极，研究其与体相离子液体不同的伏安行为；另一方面，制备不同离子液体含量为15% ~ 28%的包载离子液体硅胶和涂覆离子液体硅胶，用电化学阻抗研究其在20 oC到80 oC下电导率的变化情况. 异常的电化学行为主要表现在：1)硅胶包载离子液体导致Fc/Fc+电对的半波电位正移63.5 ~ 200 mV；2)当离子液体限域于硅胶纳米孔道中时，离子液体的电化学稳定性变差；3)包载离子液体硅胶的电导率要比涂覆离子液体的电导率高29.6% ~ 136%. 由此推断，可能是由于离子液体充满硅胶孔腔和孔道从而形成了纳米网状的离子液体导电介质. 这些结果表明，硅胶包载离子液体不仅可以作为修饰电极的优良载体，而且也有助于理解离子液体限域于硅胶纳米孔道中的限域效应.Imidazolium Ionic liquids (ILs) nano aggregates confined into nanopores of silica gel matrices (ILs-sg) modified electrodes were prepared by sol-gel process and characterized by cyclic voltammetry. Furthermore, the amounts of 15% ~ 28% ILs-sg and nano aggregates coated with ILs silica gel (ILs/sg) were prepared and their conductivities were evaluated by performing electrochemical AC impedance measurements from 20 oC to 80 oC. The abnormal results showed that, 1) comparing with the bulk IL, the confined IL had a positive shift effect of Fc/Fc+ redox potential; 2) when IL confined into a nanospace, the electrochemical stability became poor; 3) the ion conductivity of ILs-sg was 29.6% ~ 136% higher than that of ILs coated silica gel, which could be attributed to the formation of nano ionic liquid network electrolyte. These results not only illustrate that the ILs based silica gel could serve as an excellent support of modified electrode for electrochemical active substance, but also reveal that the findings are helpful to understand the electrochemical phenomena of ILs under a confinement environment.