不对称草酰胺镍配合物修饰电极的制备及其对甲醛的电催化研究

Electrocatalytic Oxidation of Formaldehyde at Glassy Carbon Electrode Modified by a μ-Oxamido -N-benzoic-N' -2-aminethyl Nickel Complex

研究了不对称配体氮苯甲酸氮乙二胺草酰胺镍配合物修饰电极的制备 ,用循环伏安法探讨了该修饰膜的电化学性质及其对甲醛的电催化氧化。在 0 .1mol·L-1NaOH溶液中 ,膜的循环伏安图在 0 .4V和 0 .3V处有一对准可逆的氧化还原峰 ,对应着Ni(Ⅱ ) /Ni(Ⅲ )的氧化还原反应过程 ,属一电子过程 ,实验结果还表明电荷在膜中的传递为扩散控制。实验测定了在 0 .1mol·L-1NaOH中 3种不同厚度修饰膜电极、扫速在 10～ 40 0mV/s范围内氧化还原峰的特征。当配合物表面含量是 9.4× 10 -10 mol·cm-2 时 ,膜中电荷的扩散系数Dct是 1.1× 10 -12 cm2 ·s-1。该修饰膜对甲醛有良好的电催化作用且稳定性高 ,连续催化 2h以上峰电流才开始下降。常温下将修饰电极置于空气中放置

A nickel complex modified electrode (p-OANi/GC) is prepared by oxidative electropolymerization of the oxamido-N-benzoic-N'-2-aminethyl nickel complex in alkaline aqueous solution. The cyclic voltamogram of the p-OANi/GC electrode exhibited a couple of quasi-reversible redox peaks at potential 0.4?V anodic and 0.32?V cathodic in 0.1 mol·L -1NaOH, which corresponds to redox of Ni(Ⅱ)/Ni(Ⅲ) in one-electron reaction. The experimental results show that the charge transfer process in the modifier film is controlled by the diffusion. The influence of scan rate and modifier loadings on peak features of p-OANi/GC is studied. From the collected data the charge diffusion coefficient in film is determined 1.1×10 -12cm 2·s -1 for a relatively thick film(R=9.4×10 -10 mol·cm -2). Noticeably, both the electrocatalysis and stability of the p-OANi/GC for oxidation of formaldehyde and methanol is excellent. In the formaldehyde and methanol solution, the anodic peak current didn't decay until cyclic voltammetric scanning 120 minutes, and the electrocatalysis is well as before when the p-OANi/GC is hold in air for ten days.