Keggin型SiW11O39Co（Ⅱ）（H2O）^6-的合成、表征及电化学性质

在中性水溶液中合成了Keggin型钴取代硅钨杂多阴离子SiW11O39Co（II）（H2O）6-（SiW11Co）,并进行了IR、UV-vis和循环伏安表征.IR和UV-vis实验表明,SiW11Co在960,904、810和748cm-1处有四个特征振动吸收峰,分别对应于Si-Oa、W=Od、W-Ob-W和W-Oc-W的反对称伸缩振动.在200nm和252nm处有两个很强的紫外吸收峰,分别对应于Od→W和Ob,Oc→W荷移跃迁;在400nm和546nm处有两个较强的可见吸收峰,分别对应于O（dH2O）→dCo和Ob,Oc→dCo荷移跃迁.循环伏安和交流阻抗实验表明SiW11Co有一对Co波和两对W-O骨架波,前者的电极过程具有不可逆的性质,为电荷传递动力学控制过程;后者的电极过程具有可逆的性质,为扩散控制过程.两者的电极过程均涉及H＋.

Synthesis,Characterization and Electrochemical Properties of Keg-gin-type Co-substituted Heteropolyanion SiW11O39Co（Ⅱ）（H2O）6-

Keggin-type Co（II）-substituted heteropolyanion SiW11O39Co（II）（H2O）6-（SiW11Co） was synthesized in neutral aqueous solution and characterized by IR, UV-vis and cyclic voltammetry.IR and UV-vis experimental results showed that SiW11Co has four characteristic absorption peaks at the position of 960,904、810 and 748 cm-1 corresponding to the anti-symmetric stretching vibration of Si-Oa, W=Od, W-Ob-W and W-Oc-W, respectively, and two strong UV absorp-tions at near 200 nm and 252 nm attributed to Od→W and Ob,Oc→W charge-transfer transition as well as two visible absorption peak at near 400 nm and 546 nm attributed to Od （H2O）→dCo and Ob,Oc→dCo charge-transfer transition.Cyclic voltammetry and alternating current impedance experiments revealed a pair of Co redox wave and two pairs of W-O skeleton-waves for SiW11Co.The Co redox wave is an electron-transfer-controlled and irreversible process.The W-O skeleton-waves are diffusion-controlled and reversible processes.All of the electrode processes are involved in H＋.