中文摘要：

采用动力学方法研究了在水悬浮液中δ-MnO2颗粒物对P-25 TiO2光催化降解甲基橙活性的影响,并利用紫外-可见漫反射光谱（DRS）和光致发光光谱（PL）对受δ-MnO2污染前后的TiO2样品进行了表征.动力学研究结果表明,在3种不同初始pH值条件下,δ-MnO2对TiO2光催化剂都具有明显的致毒效应,共存δ-MnO2的浓度越大,致毒效应越明显.表征结果表明,由于δ-MnO2与TiO2之间的界面接触,使得TiO2吸收带边蓝移,紫外光区的吸收强度降低,光致发光信号（PL）明显减弱.因此,δ-MnO2导致TiO2的禁带宽度增大,光利用率降低,并且是光生电子与空穴的复合中心。

英文摘要：

The influences of 6-MnO2 particles on the photocatalytic activity of P-25 TiO2 were investigated with kinetical method through the photocatalytic degradation of methyl orange. The TiO2 photocatalyst, before and after being contaminated by 6-MnO2, was characterized with UV-visible diffuse reflectance spectroscopy（ UV- Vis DRS） and photoluminescence（PL）. The dynamics results show the distinct existence of poisoning effect of 6-MnO2 on TiO2 photocatalysis at different initial pH values. The higher the concentration of the 6-MnO2, the more evident the poisoning effect. The characterizations indicate that the absorption band edge of TiO2 is blueshifted and the intensity is decreased, and the intensity of PL signals of TiO2 is suppressed due to the contact between 6-MnO2 and TiO2. Therefore, the presence of 6-MnO2 increases the band gap and causes the decrease of UV absorption of TiO2 , and 6-MnO2 can also act as a recombination centers of photoinduced electron-hole. The effects of δ-MnO2 particles in environment on the stability of TiO2 photocatalyst were revealed.