ZnO hierarchical micro/nanoarchitectures: Solvothermal synthesis and structurally enhanced photocatalytic performance
ZnO hierarchical micro/nanoarchitectures: Solvothermal synthesis and structurally enhanced photocatalytic performance
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DOI：
10.1002/adfm.200700973
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发表时间：
2008-04-11
影响因子：
19
通讯作者：
Zhang, Yugang
中科院分区：
文献类型：
--
作者：
Lu, Fang;Cai, Weiping;Zhang, Yugang
一种新型的 ZnO 分级微/纳米结构是通过简单的溶剂热方法在乙二胺 (EDA) 水溶液中制备的。这种复杂的结构是核/壳结构，由密集的纳米片构建的网络组成，这些网络位于六角金字塔状的微晶体（核心部分）上。 ZnO 六边形微锥体的外表面由基面（棒上的 000 (1)）和侧平面 {棒 11 上的 0 (1)} 组成。纳米片的厚度均匀，约为 10 nm，并具有单晶结构，其片平面表面为 {2 (1) over bar(1) over bar0} 平面。这些纳米片以60度或120度的角度相互交错和重叠，并在微锥体上组装成可辨别的网状或网格状形态（网格尺寸约100 nm），表现出较高的比表面积（185.6 m(2) g(-1)）。这种ZnO微/纳米结构是ZnO纳米结构家族中的新型结构。它的形成取决于 EDA 溶液的浓度以及锌源的类型。基于对时间依赖性形态演化过程的观察，提出了两步顺序生长模型。重要的是，这种结构的ZnO表现出强烈的结构诱导的光催化性能增强，并且与其他纳米结构的ZnO（例如纳米粒子、纳米片和纳米针的粉末）相比，对甲基橙的光降解表现出更好的光催化性能和耐久性。这主要归因于其较高的表面积与体积比和抗聚集稳定性。这项工作不仅深入了解了溶液相合成体系中复杂ZnO微/纳米结构的分级生长行为，而且还提供了一种提高ZnO光催化性能的有效途径，如果它们具有相同的分级微/纳米结构并具有开放和多孔的纳米结构表面层，也可以扩展到其他催化剂，例如本质上优异的TiO2。
A novel ZnO hierarchical micro/nanoarchitecture is fabricated by a facile solvothermal approach in an aqueous solution of ethylenediamine (EDA). This complex architecture is of a core/shell structure, composed of dense nanosheet-built networks that stand on a hexagonal-pyramid-like microcrystal (core part). The ZnO hexagonal micropyramid has external surface that consist of a basal plane (000 (1) over bar) and lateral planes {0 (1) over bar 11}. The nanosheets are a uniform thickness of about 10 nm and have a single-crystal structure with sheet-planar surfaces as {2 (1) over bar(1) over bar0} planes. These nanosheets interlace and overlap each other with an angle of 60 degrees or 120 degrees, and assemble into a discernible net- or grid-like morphology (about 100 nm in grid-size) on the micropyramid, which shows a high specific surface area (185.6 m(2) g(-1)). Such a ZnO micro/nanoarchitecture is new in the family of ZnO nanostructures. Its formation depends on the concentration of the EDA solution as well as on the type of zinc source. A two-step sequential growth model is proposed based on observations from a time-dependent morphology evolution process. Importantly, such structured ZnO has shown a strong structure-induced enhancement of photocatalytic performance and has exhibited a much better photocatalytic property and durability for the photodegradation of methyl orange than that of other nanostructured ZnO, such as the powders of nanoparticles, nanosheets, and nanoneedles. This is mainly attributed to its higher surface-to-volume ratio and stability against aggregation. This work not only gives insight into understanding the hierarchical growth behaviour of complex ZnO micro/nanoarchitectures in a solution-phase synthetic system, but also provides an efficient route to enhance the photocatalytic performance of ZnO, which could also be extended to other catalysts, such as the inherently excellent TiO2, if they are of the same hierarchical micro/nanoarchitecture with an open and porous nanostructured surface layer.