退火温度对基于嵌段共聚物稳定的双金属纳米粒子制备的（中空Au—Ag纳米粒子）／TiO2复合纳米材料光催化活性的影响

以嵌段共聚物稳定的中空双金属（Au—Ag）纳米粒子为基础，与TiO2的溶胶-凝胶复合，制备出（中空Au—Ag纳米粒子）／riO：复合纳米材料，研究了退火温度对该复合纳米材料的结构、表面特性和光催化活性的影响。用X-射线衍射（XRD）、透射电镜（TEM）对（中空Au—Ag纳米粒子）／TiO2复合纳米材料的结构进行了表征，用热重分析（TGA）测量了其中的碳含量，用氮气吸附技术测量了比表面积和孔体积，用光降解亚甲基（MB）蓝测量了样品的光催化活性。结果表明，对制备的（中空Au—Ag纳米粒子）trio：复合纳米材料，当退火温度为400℃时，Ti02为非晶结构，当退火温度为450℃时，TiO2为锐钛矿结构，当退火温度进一步增加到500oC时．晶型不变，但结晶度增加；而比表面积随着退火温度的增加而下降。光催化活性结果表明。当退火温度为450℃时，（中空Au—Ag纳米粒子）／TiO2复合纳米材料具有最好的光催化活性。

Fabrication of AgA u alloy-TiO_2 core-shell nanoparticles and their photocatalytic properties

In this paper, for improving the photocatalytic efficiency of titania(TiO2) nanoparticles(NPs), Ag Au alloy-TiO2 core-shell NPs are fabricated via a sol-gel(SG) process in the presence of Ag Au alloy NPs with block copolymer shells as templates. The photocatalytic activities of the Ag Au-TiO2 NPs on the photodecomposition of methylene blue(MB) are investigated. The Ag Au-TiO2 composite NPs coated with 5.0% titania related to block copolymers show higher photocatalytic activity than the other samples in which the titania contents are larger than 5.0%. The results indicate that the increase of the thickness of the TiO2 shell leads to the decrease of the photocatalytic activity.