咪唑离子液体中氧在MnO_2电极上的电化学性能

Electroreduction of oxygen on MnO_2 electrode in imidazolium ionic liquid electrolytes

以N-甲基咪唑和不同链长的卤代烷烃为原料,合成了三种咪唑类的双(三氟甲基磺酰)亚胺根(TFSI―)离子液体。测定了它们的电导率与电化学窗口;并通过循环伏安、计时电流和交流阻抗等电化学方法,对三种离子液体在涂覆MnO2玻碳电极上的氧还原性能进行了研究。实验结果表明:咪唑环上侧链的链长越长其电导率越小,但对电化学窗口影响不大。分析了氧在三种离子液体中的氧还原电催化机理,比较其电化学性能,均发现咪唑环上侧链链长越短其电化学性能越好。

Three imidazolium-base ionic liquids with bis （trifluoromethanesulfone）imide as anion were synthesized using N-methyl imidazole and different chain lengths of the haloalkane as raw materials. Their conductivity and electrochemical windows were determined. Glass carbon was coated with Mn02 as a working electrode, the electrochemical oxygen reduction reaction was investigated in three hydrophobic room-temperature ionic liquids by different electrochemical methods, such as cyclic voltammogram, chronoamperometry and electrochemical impedance spectra. Experimental results show that the longer the chain length of imidazole ring on the side chain, the smaller the conductivity; but it has little effect on the electrochemical windows. The mechanism of electro-catalysis oxidation reduction reaction was analyzed in the three ionic liquids using cyclic voltammogram. Comparing their electrochemical properties, all the testing results shows that the shorter the chain length of imidazole ring on the side chain, the better the electrochemical will performance.