A Facile Template-Free Approach for the Large-Scale Solid-Phase Synthesis of CdS Nanostructures and Their Excellent Photocatalytic Performance
A Facile Template-Free Approach for the Large-Scale Solid-Phase Synthesis of CdS Nanostructures and Their Excellent Photocatalytic Performance
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DOI：
10.1002/smll.201002130
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发表时间：
2011-04-04
期刊：
影响因子：
13.3
通讯作者：
Kale, Bharat B.
中科院分区：
文献类型：
--
作者：
Apte, Sanjay K.;Garaje, Sunil N.;Kale, Bharat B.
首次在固相条件下，从块状氧化镉中简单、无模板、低温、大规模合成具有六方纤锌矿相的纳米结构CdS。新的方法涉及均匀化的氧化镉（CdO）和硫脲在不同的化学计量比在中等温度下。在所研究的CdO和硫脲的不同摩尔比中，CdO/NH_2CSNH_2摩尔比为1：2时，得到的CdS纯度最高。所得CdS纳米结构具有良好的立方形貌和高比表面积，粒径在5-7 nm范围内。的带隙的纳米结构的CdS是在2.42至2.46 eV的范围内，由于其纳米晶体的性质。在光致发光研究中，在520.34和536.42 nm处观察到发射，这是可见光谱的黄绿色区域的特征。考虑到CdS的禁带宽度在可见光范围内，在可见光照射下，对H-2的产生和有机染料的降解进行了光催化活性研究。使用以1：2的比例制备的纳米结构的CdS获得2945 μ mol h（-1）的最大H-2释放，这是本体CdS（1010 μ mol h（-1））的最大H-2释放的三倍。使用1：2的摩尔比合成的CdS显示出最大的亚甲基蓝降解（87.5%）超过60分钟的时间内，这是大约四倍高于散装CdS（22%）。这种材料的惊人性能是由于其纳米晶体性质和CdS的高表面积。该方法简单易行，是纳米技术领域的一个重大突破，也可为其他纳米结构金属硫化物的大规模合成提供一种合理的制备方案。
The simple, template-free, low-temperature, large-scale synthesis of nanostructured CdS with the hexagonal wurtzite phase from bulk cadmium oxide under solid-phase conditions is demonstrated for the first time. The novel approach involves the homogenization of cadmium oxide (CdO) and thiourea in various stoichiometric ratios at moderate temperature. Among the different molar ratios of CdO and thiourea studied, the CdO/NH2CSNH2 molar ratio of 1:2 is found to be the best to obtain highly pure CdS. The obtained CdS nanostructures exhibit excellent cubic morphology and high specific surface area with a particle size in the range of 5-7 nm. The bandgap of the nanostructured CdS is in the range of 2.42 to 2.46 eV due to its nanocrystalline nature. In photoluminescence studies, emission is observed at 520.34 and 536.42 nm, which is characteristic of the greenish-yellow region of the visible spectrum. Considering the bandgap of the CdS is within the visible region, the photocatalytic activity for H-2 generation and organic dye degradation are performed under visible-light irradiation. The maximum H-2 evolution of 2945 mu mol h(-1) is obtained using nanostructured CdS prepared in the 1:2 ratio, which is three times higher than that of bulk CdS (1010 mu mol h(-1)). CdS synthesized using the 1:2 molar ratio shows maximum methylene blue degradation (87.5%) over a period of 60 min, which is approximately four times higher than that of bulk CdS (22%). This amazing performance of the material is due to its nanocrystalline nature and the high surface area of the CdS. The proposed simple methodology is believed to be a significant breakthrough in the field of nanotechnology, and the method can be further generalized as a rational preparation scheme for the large-scale synthesis of various other nanostructured metal sulfides.