Morphology control, defect engineering and photoactivity tuning of ZnO crystals by graphene oxide--a unique 2D macromolecular surfactant.
Morphology control, defect engineering and photoactivity tuning of ZnO crystals by graphene oxide--a unique 2D macromolecular surfactant.
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DOI：
10.1039/c3cp55038a
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发表时间：
2014-02
期刊：
影响因子：
--
通讯作者：
Xiaoyang Pan;Min‐Quan Yang;Yi‐Jun Xu
中科院分区：
文献类型：
--
作者：
Xiaoyang Pan;Min‐Quan Yang;Yi‐Jun Xu
氧化锌纳米材料因其独特的物理化学和电子性能而受到广泛关注。特别是，ZnO的功能特性强烈依赖于其形态和缺陷结构，特别是对于半导体ZnO基光催化剂。在这里，我们展示了一种简单的策略，利用氧化石墨烯（GO）在液相中的独特表面活性剂特性，同时进行半导体ZnO的形貌控制、缺陷工程和光活性调节。在合成过程中，通过改变氧化石墨烯的加入量，ZnO的形貌逐渐由一维棱柱状棒状结构演变为六方管状结构，同时氧化石墨烯被转化为还原氧化石墨烯（RGO）。此外，氧化石墨烯的引入可以在ZnO晶体的晶格中产生氧空位。因此，宽禁带半导体ZnO的吸收边缘有效地延伸到可见光区，从而赋予RGO-ZnO纳米复合材料可见光光活性；相反，裸露的ZnO纳米棒仅具有紫外光活性。独特的形貌和氧空位的存在协同整合，使得RGO-ZnO纳米复合材料与具有不同结构形态和无氧空位的裸ZnO相比，具有显著增强的可见光光活性。我们的研究结果突出了二维氧化石墨烯作为一种可溶液加工的大分子表面活性剂的多功能性，以系统材料工程的方式制造具有可调形貌、缺陷结构和光催化性能的氧化石墨烯半导体纳米复合材料。
Zinc oxide (ZnO) nanostructured materials have received significant attention because of their unique physicochemical and electronic properties. In particular, the functional properties of ZnO are strongly dependent on its morphology and defect structure, particularly for a semiconductor ZnO-based photocatalyst. Here, we demonstrate a simple strategy for simultaneous morphology control, defect engineering and photoactivity tuning of semiconductor ZnO by utilizing the unique surfactant properties of graphene oxide (GO) in a liquid phase. By varying the amount of GO added during the synthesis process, the morphology of ZnO gradually evolves from a one dimensional prismatic rod to a hexagonal tube-like architecture while GO is converted into reduced GO (RGO). In addition, the introduction of GO can create oxygen vacancies in the lattice of ZnO crystals. As a result, the absorption edge of the wide band gap semiconductor ZnO is effectively extended to the visible light region, which thus endows the RGO-ZnO nanocomposites with visible light photoactivity; in contrast, the bare ZnO nanorod is only UV light photoactive. The synergistic integration of the unique morphology and the presence of oxygen vacancies imparts the RGO-ZnO nanocomposite with remarkably enhanced visible light photoactivity as compared to bare ZnO and its counterpart featuring different structural morphologies and the absence of oxygen vacancies. Our promising results highlight the versatility of the 2D GO as a solution-processable macromolecular surfactant to fabricate RGO-semiconductor nanocomposites with tunable morphology, defect structure and photocatalytic performance in a system-materials-engineering way.