掺铝氧化锌纳米晶的超声．水热协同控制合成及其光催化性能

Photocatalytic Properties of Aluminum Doped Zinc Oxide Nanocrystals Controlled Prepared via a Synergistic Ultrasonic/Hydrothermal Technique

利用超声和水热的协同控制作用高效合成出了分散好、晶体结构完整、粒径尺寸约为20nm的掺铝氧化锌(ZAO)纳米晶,通过透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)、傅里叶变换红外(FTIR)光谱仪、紫外-可见(UV-Vis)分光光度计和热重-差热分析(TG-DTA)手段对产物形貌、结构、光学性质及前驱物的热性质进行了研究,对其降解罗丹明B(RhB)的光催化效果和光催化降解机理进行了探讨.由于超声和水热的协同作用,有效控制了产物的粒径,提高了产物的结晶度.产物的紫外-可见光谱吸收峰出现在369nm左右,计算其带隙约为3.36eV.同超声法或水热法制备的产物相比,超声-水热法制备的ZAO纳米产物具有更高的光催化活性,从而使光催化降解时间缩短为原来的77.8%.ZAO纳米光催化剂能够回收再利用.

Aluminum doped zinc oxide （ZAO） nanocrystals approximately 20 nm in diameter and with good dispersity and crystallinity were efficiently synthesized through a synergistic combination of ultrasonic and hydrothermal methods. The morphologies, structures, and optical properties of these nanocrystals, as well as the thermochemistry of the precursor, were determined using transmission electron microscopy （TEM）, powder X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectroscopy, ultraviolet-visible （UV-Vis） spectroscopy, and thermogravimetric-differential thermal analysis （TG-DTA）. ZAO nanocrystals were investigated with regard to the photocatalysis of rhodamine B （RhB） in solution, including studies of degradation rates and catalysis mechanism. It was found that both the particle size and crystallinity of the material can be controlled through the ultrasonic/hydrothermal synergetic effect. The main absorption peak of the product in a typical UV-Vis spectrum appeared at ~369 nm and its energy band gap was determined to be 3.36 eV. The ZAO produced by this method exhibits enhanced photocatalytic activity; compared to catalysis by materials produced solely by ultrasonic or hydrothermal routes, the degradation time of an RhB solution is reduced by 77.8%. In addition, it was found that this ZAO photocatalyst may be recycled and used more than once.