Keggin结构的磷钨钒稀土四元杂多配合物对过氧化氢分解的催化作用

Catalysis of Tungstovanadophosphoric Heteropoly Complexes with Lanthanide on H_2O_2 Decomposition

在磷钨钒稀土四元杂多配合物中，由于Ｖ原子的作用，使其对Ｈ２Ｏ２分解的催化活性显著增加，因配合物中心原子稀土元素不同，催化活性也随之变化，其活化能与三价稀土离子的电离能有密切关系，动力学曲线为Ｓ型，实验证明，在反应过程中有反应活性中间体生成，催化性能并非由阴离子中一种元素所决定，各组成元素之间有一种“协同效应”。通过研究Ｈ２Ｏ２浓度及催化剂浓度对反应的影响，提出动力学方程并计算出了各参数值，在此基础上讨论了反应机理。

Catalytic activity of the tungstovanadophosphoric heteropoly complexes with lanthanide for H2O2 decomposition was notably increased as the result of the presence of vanadium in the complex.When the lanthanide in the center of the complex was different,the catalytic activity of the complexes also changed.The variation of the activation energy of the complexes with respect to the rare earth element ion Ln3+ is the same as that of the third ionization energy.The kinetic curve of H2O2 decomposition catalyzed by these complexes is S-shape.By investigating the effect of the catalyst concentration,initial H2O2 concentration and temperature on H2O2-decomposition,a rate equation as well as the kinetic parameters were obtained. The experimental results obtained illustrate that a less stable intermediate seems to be formed in the reaction condition for H2O2-decomposition and the catalytic activity of the complexes is not only determined by the center element,but could be attributed to the synergistic effect of the component elements of the anion in the complexes.Based on these results,a possible reaction mechanism for this reaction system is proposed.