可见光响应PANI/TiO_2和PoPD/TiO_2纳米材料的氧化机制及协同-光敏化作用  

Oxidation mechanism and synergetic-photosensitization effect of visible-light-induced PANI /TiO_2 and PoPD/TiO_2 nanocomposites

作　　者：杨传玺[1] 王炜亮[1] 董文平 王小宁[1] 宗万松[1] 

机构地区：[1]山东师范大学地理与环境学院,济南250014 [2]山东省环境科学研究院环境工程有限公司,济南250013

出　　处：《环境化学》2016年第1期102-111,共10页Environmental Chemistry

基　　金：国家自然科学基金(21207082;21577083);山东省环境保护厅项目(SDHBPJ-ZB-09)资助~~

摘　　要：利用原位氧化聚合法制备pdyaniline(PANI)/TiO_2和poly-o-phenylenediamine(PoPD)/TiO_2纳米材料,通过XRD、元素分析、UV-Vis DRS和循环伏安曲线等方式进行表征,以亚甲基蓝为模拟污染物,考察p H值以及导电聚合物/TiO_2浓度对光催化效果的影响,通过捕捉实验判定不同活性物种在光催化过程中的贡献.结果表明,PANI和Po PD没有改变TiO_2的粒径和物相,PANI/TiO_2、Po PD/TiO_2和TiO_2的禁带宽度分别为2.82 e V、2.89 e V和3.09 e V;溶液p H值越高,导电聚合物/TiO_2纳米材料的光催化活性越高;PANI/TiO_2和Po PD/TiO_2纳米材料浓度在光催化降解过程中存在的最佳值分别为1 g·L-1和1.5 g·L-1,PANI/TiO_2和Po PD/TiO_2纳米材料光催化过程中活性氧物种的贡献顺序分别为·OH>h+>·O-2,·OH≈h+>·O-2.重复利用实验结果表明制备的PANI/TiO_2和Po PD/TiO_2纳米材料具有良好的光催化稳定性.导电聚合物和TiO_2之间的协同-光敏化作用是CPs/TiO_2纳米材料光催化活性得到提高的主要原因.Polyaniline（ PANI） and poly-o-phenylenediamine（ Po PD） modified TiO2 nanocomposites were synthesized via ‘in situ ＇ oxidative polymerization method. The prepared nanocomposites was characterized by X-ray diffraction（ XRD）,elemental analysis（ EA）,UV-Vis diffuse reflectance spectrum（ DRS）,and cyclic voltammetry（ CV）. The photocatalytic activity of the prepared nanocomposites was evaluated by photocatalytic degradation of methylene blue（ MB）.The effects of initial p H value and conducting polymer（ CPs） / TiO2 concentration were evaluated,and the contribution of reactive oxidation species was determined by using trap experiment. The results indicated that the presence of PANI and Po PD did not have any impact on the crystalline grain and phase of TiO2. The estimated band gap values of the nanocomposites were approximately2.82 e V,2. 89 e V and 3. 09 e V for PANI / TiO2, Po PD/TiO2 and TiO2 respectively. The photocatalytic degradation rate of MB increased with initial p H value from p H 3.5 to p H 11.5. The optimum concentrations of PANI / TiO2 and Po PD / TiO2 nanocomposites were 1 g·L-1and 1.5 g·L-1,respectively. The order of ROS contribution was ·OH 〉 h＋〉·O-2for PANI / TiO2,and ·OH ≈ h＋〉·O-2for PANI / TiO2. In addition,PANI / TiO2 and Po PD / TiO2 nanocomposites showed excellent photocatalytic stability after 5 recycle times under light irradiation. The synergetic-photosensitization effect between conducting polymer and TiO2 was a key reason for the enhamced photocatalytic activity of CPs / TiO2 nanocomposites.

关 键 词：可见光响应 导电聚合物 二氧化钛 氧化机制 协同-光敏化作用 

分 类 号：TB383.1[一般工业技术—材料科学与工程] X505[环境科学与工程—环境工程]