TiO_2纳米管半波脉冲直流电光电催化还原Cr(Ⅵ)

Photoelectrocatalytic Reduction of Cr(Ⅵ) over TiO_2 Nanotube Arrays under Half-wave Pulsed Direct Current

报道了在半波脉冲直流电(h-DC)作为电压驱动下,以阳极氧化法制备的TiO2纳米管(TNT)为工作电极,紫外光光电催化(PEC)还原Cr(VI)的研究.半波脉冲直流电相比稳压直流电(DC)和交流电(AC)具有更佳的载流子分离和光电催化作用.探讨了电压大小、频率及电解质NaCl浓度对Cr(VI)催化还原反应的影响.TNT光电催化和电催化还原Cr(VI)效率随外加电压和频率的增大而增大,但是频率过高对反应有一定的抑制作用.电解质NaCl对反应的影响不显著,这是因为在重金属还原体系中,NaCl作为活性氯物种的母体和增强溶液导电性的作用体现得不明显.

In this paper,the photoelectrocatalytic（PEC） reduction of Cr（VI） over anodized TiO2 nanotube arrays under UV-light irradiation using the half-wave pulsed direct current（h-DC） as the applied voltage was reported.This mode of voltage brings about better separation of photogenerated electrons and holes,resulting in much higher photoelectrocatalytic efficiency than either the conventional direct current（DC） or the alternate current（AC）.Under the half-wave pulsed direct current,the influence factors such as the value and frequency of the voltage,also concentration of the electrolyte（NaCl）,on the PEC reduction of Cr（VI） were investigated.The PEC reduction rate increased with increasing voltage and frequency,but could be restrained by a high frequency.The concentration of NaCl exhibited little effect on the PEC reduction reaction of Cr（VI）,for the weak function of active chlorine species and electric conduction in the heavy metal reduction system.