甲醛在脯氨酸膜修饰电极上的电催化氧化

Electrocatalytic oxidation of formaldehyde on the proline film modified electrode

应用电化学法和光谱电化学法研究了脯氨酸膜修饰电极的制备 ,用循环伏安法探讨了该膜的电化学性质及其对甲醛的催化氧化 .该电极催化稳定性良好 ,在NaOH溶液中 ,掺杂Ni (Ⅱ )后的脯氨酸膜修饰电极对甲醛和乙醇的氧化均有一定的催化活性 。

The proline film modified electrode and its electrochemical behavior was studied by cyclic voltammetry and spectroelectrochemistry . After incorporation of Ni(Ⅱ), the cyclic voltammograms of the proline Ni(Ⅱ) film electrode exhibited a typical redox peak, which appeared at potential of 0.52 V anodic and 0.44 V cathodic in NaOH. The formal potentials E ' were linearly dependent on the pH, and the peak currents ip were linearly dependent on the square root of the scan rates,thus charge transfer in the film was controlled by diffusion. The diffusion coefficient is figured out to be 2×10 -10 cm 2·s -1 . The catalytic oxidation peaks of formaldehyde and ethanol occurred at 0.67 V and 0.62 V respectively,much more negative than the potential at Pro/GC and the bare glassy carbon (GC) electrode in 0.1 mol·L -1 NaOH. Experimental results showed that the reaction orders of formaldehyde and OH - were 1 and 2 respectively. The anodic peak. currents of formaldehyde and ethanol were proportional to their concentrations between 10 -6 ～10 -4 mol·L -1 and 3×10 -4 ～3×10 -3 mol·L -1 respectively. More importantly, the electrode stability in electrocatalytic oxidation of formaldehyde was very good . Cyclic scanning 120min, the anodic peak current of formaldehyde decreased 1/10 and nearly turned to be stable at last.