采用溶胶-凝胶法制备了系列生物质改性复合纳米TiO_2。以亚甲基蓝溶液为模拟污染物,考察了其可见光催化活性,并确定了最佳制备工艺。通过X射线光电子能谱(XPS)、X射线衍射(XRD)、场发射扫描电镜(FESEM)、紫外-可见漫反射光谱(UV-Vis-DRS)、荧光光谱(PL)等手段对催化剂样品进行了表征。实验结果表明,催化剂对亚甲基蓝的光催化降解适应一级反应动力学,复合TiO_2和纯TiO_2的反应速率常数分别为0.4990 h-1和0.0305h-1,且复合催化剂实现了C、N、S、P、K等多元素的共掺杂。相比纯TiO_2,复合TiO_2的比表面积增大,结晶度升高,光生载流子复合率降低,吸收边带红移,禁带宽度窄化了0.09 e V。
Using glucose and sucrose as the electron donors,the photocatalytic hydrogen evolution over Pt/TiO2 was investigated.Glucose and sucrose enhance notably the activity for hydrogen generation.The amounts of produced H2 increase almost proportionally to time within 5 h irradiation in the reaction systems of the two electron donors.The effect of the initial concentration of glucose and sucrose on the reaction rate is consistent with the Langmuir-Hinshelwood kinetic model.After 5 h irradiation,the COD(chemical oxygen demand) in the reaction system of glucose and in that of sucrose decrease by 33.2%,11.4% respectively.The effect of electron donors on the flat-band potential of conduction band of TiO2 electrode was investigated.The flat-band potential of conduction band of TiO2 electrode in the presence of the electron donors shifts negatively,and the shift in the presence of glucose is larger than that in the presence of sucrose due to glucose having a larger adsorption amount on TiO2.