Ag/CdS heterostructural composites: Fabrication, characterizations and photocatalysis
Ag/CdS heterostructural composites: Fabrication, characterizations and photocatalysis
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DOI：
10.1016/j.apsusc.2014.06.022
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发表时间：
2014-09-15
影响因子：
6.7
通讯作者：
Zhang, Zhuxia
中科院分区：
文献类型：
--
作者：
Liu, Yang;Chi, Mei;Zhang, Zhuxia
采用超声辅助多元醇和水热法成功合成了Ag/CdS异质结构材料。在水热条件下，吸附在银纳米线上的硫脲释放出S ~（2-），与相邻的Cd ~（2+）离子反应，在银纳米线上形成CdS团簇。随后，Ag/CdS复合材料通过CdS聚集、Ostwald熟化和择优生长形成核壳结构。采用XRD、SEM和TEM对所得复合材料的结构和形貌进行了表征，结果表明，复合材料是以Ag纳米线为核，CdS颗粒为壳的复合材料。研究了Ag/CdS核壳材料的光催化性能。分别采用纯CdS、纯Ag和Ag/CdS复合材料对亚甲基蓝的降解进行了对比研究。结果表明，Ag/CdS复合材料具有较高的光催化降解效率。此外，Ag/CdS复合材料的稳定性有所提高，光催化活性在4次循环后基本保持不变。Ag/CdS复合材料的光催化活性增强主要归因于光生电子从CdS向Ag纳米线的转移，而光生空穴仍保留在CdS的价带中。因此，光生电子和空穴的有效分离以及由此产生的OH自由基极大地提高了Ag/CdS复合材料的光催化效率。(C)2014爱思唯尔有限公司版权所有。
Ag/CdS heterostructural materials were successfully synthesized by ultrasound-assisted polyols and hydrothermal method. Under hydrothermal condition, thiourea adsorbed on Ag nanowires releases S2- ions, which react with vicinal Cd2+ ions to form CdS clusters on Ag nanowires. Thereafter, the Ag/CdS composites grow into core-shell structure through CdS aggregation, Ostwald ripening, and preferential growth. The obtained core-shell structures and morphologies were investigated by XRD, SEM, and TEM; the experimental results indicate that the composites are composed of Ag nanowires serving as the core and CdS particles as the shell. The photocatalytic property of Ag/CdS core-shell materials was then investigated in detail. Comparing studies on the degradation of methylene blue were employed by using pure CdS, pure Ag, and Ag/CdS composites, respectively. The results show that the Ag/CdS composites possess higher photocatalytic degradation efficiency. Moreover, the Ag/CdS composites show improved stability, and the photocatalytic activity remains almost unchanged after four recycles. The enhanced photocatalytic effect for Ag/CdS composites is mainly attributed to the photogenerated electron transfer from CdS to Ag nanowire, while photogenerated holes still remain in CdS's valence band. Consequently, the effective separation of photogenerated electrons and holes and the resulting OH radicals improve the photocatalytic efficiency of Ag/CdS composites greatly. (C) 2014 Elsevier B.V. All rights reserved.