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应用循环伏安、方波伏安和交流阻抗法研究了Keggin型缺位硅钨杂多阴离子SiW11O398-(SiW11)在0.1mol.L-1NaHSO4+Na2SO4溶液中的电化学性质及其对H2O2还原的间接电催化作用.结果表明,SiW11的酸性水溶液在玻碳(GC)电极上显示两对可逆的还原-氧化波,对应的电荷迁移数均为1,且有2个质子参与反应.根据第1对波的还原峰电流与扫描速率平方根关系得到SiW11在溶液中的扩散系数DO为8.92×10-6cm2.s-1.SiW11对H2O2的还原具有明显的电催化活性,催化峰电位随溶液pH的降低而正移,峰电流增大.质子H+在催化反应中起协同促进作用.实验测定该电催化过程的均相准一级反应速率常数为0.30 s-1.SiW11电催化还原H2O2的机理被认为是经过形成所谓“七配位过氧化物”而发生的.
The electrochemical properties of Keggin-type absence of SiW11O398- (SiW11) in 0.1mol.L-1NaHSO4 + Na2SO4 solution and its effect on reduction of H2O2 were investigated by cyclic voltammetry, square wave voltammetry and AC impedance spectroscopy Indirect electrocatalysis.The results show that the acidic water solution of SiW11 shows two pairs of reversible reduction-oxidation waves on the glassy carbon electrode, the corresponding charge transfer numbers are all 1, and 2 protons are involved in the reaction.According to the first The reduction of the wave peak current and the square root of the scan rate obtained SiW11 in the solution diffusion coefficient DO was 8.92 × 10-6cm2.s-1.SiW11 H2O2 reduction has obvious electrocatalytic activity, catalytic peak potential with the solution pH And the peak current increases.The proton H + plays a synergistic role in the catalytic reaction.The average quasi-first-order reaction rate constant of the electrocatalytic process is 0.30 s-1.The mechanism of the electrocatalytic reduction of H2O2 by SiW11 It is believed that this occurs through the formation of so-called “seven-coordinated peroxide”.