Facile synthesis of sheet-like ZnO assembly composed of small ZnO particles for highly efficient photocatalysis
Facile synthesis of sheet-like ZnO assembly composed of small ZnO particles for highly efficient photocatalysis
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轻松合成由小 ZnO 颗粒组成的片状 ZnO 组件，用于高效光催化
DOI：
10.1039/c3ta10218a
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发表时间：
2013-01-01
影响因子：
11.9
通讯作者：
Fu, Honggang
中科院分区：
文献类型：
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作者：
Hong, Yu;Tian, Chungui;Fu, Honggang
我们报道了一种有效的绿色前驱体制备由小ZnO颗粒组成的片状ZnO组件的方法，该方法在紫外光照射下表现出良好的光催化性能。该工艺包括首先制备锌甘油前体，然后煅烧将其转化为片状ZnO组件。通过改变煅烧温度，可以很容易地调整片状ZnO组件的微观结构，包括晶粒尺寸、结晶度和比表面积。随着煅烧温度的升高，结晶度随晶粒尺寸的增大而增大。光催化实验表明，所制备的ZnO片材在紫外光照射下具有良好的光降解有机染料的活性。ZnO-600（600℃煅烧）表现出最好的光催化活性，优于P25 TiO2作为商业基准光催化剂。此外，由于10 μm的大粒径，光催化后的片状ZnO组件可以很容易地通过过滤或低速离心（或自然沉降）从反应体系中分离出来，有利于分离和重复使用。经过5次循环使用，ZnO-600的活性没有出现明显的下降，证实了其良好的循环使用活性。结合x射线光电子能谱（XPS）和BET测试，我们发现BET表面积和结晶度的协同作用导致了片状ZnO光催化剂的良好性能。特别是，由于其片状结构，ZnO可以有效地与Ag颗粒结合，通过与少量Ag NPs（质量约1%）的复合，使其光催化活性提高了3倍以上。该方法处理简单，重现性好，收率高，制备的材料性能好，具有良好的应用前景。
We report an effective and green precursor-based route for preparing a sheet-like ZnO assembly composed of small ZnO particles, which showed good photocatalytic performance under UV light irradiation. The process involved first preparing a zinc glycerol precursor and then calcination to transform it into a sheet-like ZnO assembly. The microstructure of the sheet-like ZnO assembly, including the crystallite size, crystallinity degree and Brunauer–Emmett–Teller (BET) specific surface area, could be easily tuned by changing the calcination temperature. With an increase in calcination temperature, the crystallinity degree could be improved along with an increase in the crystallite size. Photocatalytic tests indicated that the as-prepared ZnO sheets showed good activity for photo-degradation of organic dye under UV light irradiation. ZnO-600 (calcination at 600 °C) exhibited the best photocatalytic activity, which was superior to that of P25 TiO2, a commercial benchmark photocatalyst. Furthermore, the sheet-like ZnO assembly could be readily separated from the reaction system by filtration or low-speed centrifugation (or natural sedimentation) after photocatalytic use due to the large particle size of 10 μm, which is favorable for separation and reuse. After 5 recycles, the ZnO-600 did not exhibit an obvious loss in activity, confirming its good activity upon recycling. By combining X-ray photoelectron spectroscopy (XPS) and BET tests, we found that the synergy of the BET surface areas and crystallinity resulted in the good performance of the sheet-like ZnO photocatalyst. In particular, due to the sheet-like structure, the ZnO could effectively combine with Ag particles, resulting in a large increase in the photocatalytic activity by more than 3 time by compounding with a small amount of Ag NPs (about 1% by mass). The present route is promising for the application of ZnO-based photocatalysts due to its easy handling process, good reproducibility, high yield and the good performance of the resulting materials.