银负载二氧化钛纳米管阵列的制备及光催化性能

Preparation of Silver Loaded Titania Nanotube Arrays and Their Photocatalytic Performance

采用电化学阳极氧化法在金属钛表面制得了二氧化钛纳米管阵列（TNTA）,通过甲醛还原Ag＋的方法,使二氧化钛纳米管表面负载了Ag纳米粒子（Ag/TNTA）。利用扫描电镜（SEM）、X-射线衍射仪（XRD）对样品微观结构进行了表征,并利用双光束紫外-可见分光光度计检测了样品对臧红T降解的催化性能。结果表明：得到的TNTA管壁平整,管径为85～120nm,管状结构的排列高度有序,Ag在TNTA上的负载量随着在银氨溶液和甲醛溶液中的浸泡次数而增加,其中交替浸泡3次的Ag/TNTA对臧红T的降解效果最佳,交替浸泡5次和7次时,由于负载过多的Ag纳米粒子不利于光生电子-空穴对的分离,催化作用反而下降。与TNTA对臧红T的降解作用相比,Ag/TNTA复合结构的降解作用明显增强,说明Ag/TNTA复合结构的光催化性能较好。

In this paper, the titania nanotube arrays were prepared via an electrochemical anodic oxidation method. Using formaldehyde as a reducing agent, silver ions were turned into Ag nanoparticles, and then loaded on the surface of titanium dioxide nanotubes. Scanning electron microscope （SEM） and X-ray diffraction （XRD） were used to characterize the microstructure of the as-prepared samples. The photo-degradation effect of safranine T by the samples was tested by a double beam UV visible speetrophotometer. The results show that the pipe walls of the regular nanotubes are very smooth and the diameters of which are about 85-120 nm. The capacity of Ag on TNTA increased with the soaking times in silver-ammonia solution and formaldehyde solution. The obtained Ag/TNTA alternatively immersed 3 times has the best degradation efficiency of safranine T. The degradation efficiency decreased for the Ag/TNTA soaked 5 or 7 times due to inhibitation of the separation of photo generated electrons and holes which result from too much Ag nanoparticles loaded. For the degradation of safranine T,Ag/TNTA is more obvious than TNTA,suggesting that Ag/TNTA composite has better photocatalytic performance.