TiO2光电催化中光生电子降解对苯醌的行为研究

通过施加外加偏压把TiO2/Ti薄膜阳极产生的光生电子转移到阴极,并对其在阴极的电化学行为进行了研究.用水杨酸探针法对阴极溶液中产生的活性氧自由基进行了检测,探讨了pH值、恒电流值和连接类型等因素对阴极室溶液中对苯醌降解效果的影响.实验结果表明,在酸性条件下,转移至阴极的光生电子可将溶液中的溶解氧还原生成H2O2,再进而生成·OH;在pH值为2.0、恒电流为3.5mA和阳离子膜作为反应器双室连接类型的条件下,在60min内,阴极溶液中对苯醌的降解率可达到82.3%.

The behaviors of photoinduced electrons on the degradation of the p-benzoquinone in TiO2 based photoelectrocatalytic process

Photoinduced electrons were formed by transferring from the TiO2/Ti thin film anode to the cathode under an anode bias potential supply. In this paper, the chemical behaviors of as formed photoinduced electrons were investigated in the cathodic solution, and the generated reactive oxygen species were identified by a spectrophotometric method using salicylic acid as the molecular probe. Additionally, the effects of initial pH, constant current value, and ion exchange membrane on the p-benzoquinone degradation efficiency of cathode compartment were also investigated, respectively. Experimental results shows that H2O2 and ·OH could be gradually formed by reduction from between the dissolved oxygen and as-formed photoinduced electrons under an acid condition. The degradation of p-benzoquinone could reach 82.3% within 60min under the following optimum conditions: the initial pH=2.0, constant current value=3.5 mA, and using a cation membrane as the connected model between anode and cathode compartment.