微弧氧化法制备WO_3/TiO_2光电极及光催化性能研究

PREPARATION AND PHOTOCATALYTIC PERFORMANCE OF WO_3/TiO_2 PHOTOELECTRODES BY MICRO-ARC OXIDATION METHOD

采用微弧氧化工艺,在不同浓度的钨酸钠电解液中制备WO3/TiO2光电极,以罗丹明B为目标污染物,研究了电解液的组成对膜层结构与光催化性能的影响。结果表明,在不同电解液中制备的光电极膜层表面均为多孔结构。在电压160 V,1 g/L NaOH+3 g/L NH4F+20 g/L Na2WO4的电解液中,微弧氧化10 min制得的光电极光催化活性最好。用150 W氙灯照射30 min后,WO3/TiO2光电极对罗丹明B的降解率为72.7%,比TiO2光电极提高了36.3%。光催化过程符合准1级反应动力学,速率常数为5.8×10-3 min-1。

W-doped/undoped TiO2 nanotube array photoelectrodes were successfully fabricated in sodium tungstate solution with different concentrations, using the Micro-arc oxidation method. The effects of electrolyte on the film structure and photocatalytic properties were assessed by the degradation of rhodamine B under xenon light illumination. The results showed that the surface of photoelectrode prepared in different electrolytes were all porous. Photoelectrode fabricated by the method of Micro-arc oxidation process possessed the optimum photocatalytic activity, under the conditions of 10 minutes, the mixed solution ofNaOH 1 g/L, NH4F 3 g/L and Na2WO4 20 g/L. The degradation rate of Rh.B by WO3/TiO2 photoelectrode was 72.7% after 30 min illuminationand improved by 36.3% compared with TiO2 photoelectrode. The degradation of Rh.B was fitted to the pseudo-first order kinetic, and the pseudo-first order kinetic constant was 5.8× 10^-3 min^-1.