新型复合电极与偶氮染料分子的氧化降解反应的研究

Studies on the Novel Composite Electrode and Oxidation of Azo Dye Molecule

介绍了具有合成H2 O2 和光催化性能的双功能新型复合电极 .双功能复合电极是将TiO2 /C光催化剂负载在具有合成H2 O2 性能的新型载体上形成的 .在光反应器中 ,复合电极作阴极 ,钌 -钛不溶性电极作阳极 ,低压汞灯作光源 ,实现了光化学氧化与光催化氧化在同一电极 /溶液界面上的联合作用 .当反应器工作时 ,复合电极中的TiO2 /C光催化层表面进行着光催化反应 ,在载体的三相界面上进行着O2 的 2电子还原生成H2 O2 的电化学反应 ,电流效率达 82 %(J =15mA/cm2 ) ,为·OH自由基的生成提供了物质源 ,而且氧的 2电子还原反应电位使其表面的TiO2 获得相对于平带电位约 +0 .5V的阳极偏压 ,改善了TiO2 的光催化活性 .实验结果表明 ,复合电极对提高偶氮染料分子活性艳红 (K 2BP)的氧化降解速度起了重要作用 .实验发现偶氮染料分子在复合电极表面的吸附量与反应速度密切相关 .文中讨论了复合电极的作用原理及偶氮染料分子的氧化降解过程 .

A novel composite electrode which has the functions of synthesizing H2O2 and photocatalysis is reported. This double function composite electrode was prepared by loading photocatalyst TiO2/C on a novel substrate which can synthesize H2O2. In a photoreactor, the composite electrode was used as cathode, a Ru-Ti electrode as anode, a lower pressure Hg lamp as light source. Combining effect of oxidation of photochemistry and photocatalysis exists at the same interface of electrode-solution. The photocatalytic reaction took place on the surface of the TiO2/C, meanwhile H2O2 was produced at the gas-liquid-solid interfaces of the substrate. Current efficiency attained a value of 82% (J = 15 mA/cm(2)), and the potential of reduction of O-2 by 2e made TiO2 gaining about + 0.5 V anodic bias (vs. flatband potential) which is very important to improve the photocatalytic activity of TiO2. The experimental results show that the composite electrode plays an important role in enhancing the oxidation rate of the azo dye molecules. It was found that the oxidation rate of the azo dye molecules is related to its adsorption amount on the surface of composite electrode. Also, the principle of action of the composite electrode and oxidation degradation process of the azo dye molecules were discussed.