Facile synthesis and photocatalytic properties of ZnO core/ZnS-CdS solid solution shell nanorods grown vertically on reductive graphene oxide.
Facile synthesis and photocatalytic properties of ZnO core/ZnS-CdS solid solution shell nanorods grown vertically on reductive graphene oxide.
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DOI：
10.1039/c5dt00293a
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发表时间：
2015-05
影响因子：
4
通讯作者：
Jimeng Xu;H. Sang;Xitao Wang;Kang Wang
中科院分区：
文献类型：
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作者：
Jimeng Xu;H. Sang;Xitao Wang;Kang Wang
本研究结合水热法和离子交换技术，将ZnS-CdS固溶体敏化ZnO纳米棒固定在石墨烯片上，研究了壳层中CdS含量对光吸收和光催化性能的显著影响。电镜图像显示，制备的纳米复合材料显示出三明治状的3D结构，由ZnO纳米棒和垂直生长在石墨烯片两侧的ZnxCd1-xS或CdS壳组成。UV/Vis DRS表明，与RGO/ZnO和RGO/ZnO@ZnS相比，固溶体敏化纳米复合材料增强了可见光吸收，并表现出带边红移。荧光发射光谱表明，在壳层上沉积适当CdS/ZnS比的CdS和石墨烯的掺入改善了电荷分离。光催化实验表明，RGO/ZnO@ZnxCd1-xS纳米复合材料对H2的光催化活性明显高于RGO/ZnO纳米棒和RGO/ZnO@ZnS核/壳纳米棒。在300 W氙灯照射下，RGO/ZnO@Zn0.6Zn0.4S样品的光催化产氢率最高，为1865 μmol h(-1) g(-1)，活性分别是RGO/ZnO和RGO/ZnO@ZnS样品的2.1倍和1.4倍。在可见光（>420 nm）照射下，RGO/ZnO和RGO/ZnO@ZnS纳米棒几乎没有活性，而RGO/ZnO@Zn0.6Zn0.4S的产氢速率为160 μmol h(-1) g（-1）。复合材料的性能得到了很大的改善，这可以归因于光吸收的增加和有效的电荷分离。
In the present study, ZnS-CdS solid solution sensitized ZnO nanorods were anchored on graphene sheets by combining a hydrothermal process and ion exchange technique, and the significant influence of CdS content in the shell on photo absorption and photocatalytic performance were investigated. Electron microscopic images reveal that the as-prepared nanocomposites display a sandwich-like 3D structure, consisting of ZnO nanorods with a ZnxCd1-xS or CdS shell grown vertically on both sides of the graphene sheets. UV/Vis DRS shows that the solid solution sensitized nanocomposites have enhanced visible light absorption and also exhibited a red-shift of the band-edge as compared to RGO/ZnO and RGO/ZnO@ZnS. Fluorescence emission spectra indicate that the deposition of CdS on the shell with an appropriate CdS/ZnS ratio and the incorporation of graphene causes improved charge separation. The photocatalytic experiments demonstrate that the RGO/ZnO@ZnxCd1-xS nanocomposites possess much higher photocatalytic activity for H2 evolution than the RGO/ZnO nanorods and RGO/ZnO@ZnS core/shell nanorods. Under the irradiation of a 300 W Xe lamp, the highest photocatalytic hydrogen production rate of 1865 μmol h(-1) g(-1) is observed over the RGO/ZnO@Zn0.6Zn0.4S sample, which is about 2.1 and 1.4 times more active than RGO/ZnO and RGO/ZnO@ZnS, respectively. Under the irradiation of visible light (>420 nm), the RGO/ZnO and RGO/ZnO@ZnS nanorods are barely active, whereas RGO/ZnO@Zn0.6Zn0.4S displays a hydrogen production rate of 160 μmol h(-1) g(-1). The highly improved performance of the composites can be ascribed to the increased light absorption and efficient charge separation.