Metal-organic framework assisted and in situ synthesis of hollow CdS nanostructures with highly efficient photocatalytic hydrogen evolution
Metal-organic framework assisted and in situ synthesis of hollow CdS nanostructures with highly efficient photocatalytic hydrogen evolution
复制标题
金属有机骨架辅助原位合成空心CdS纳米结构并高效光催化析氢
DOI：
10.1039/c9dt00603f
复制
发表时间：
2019
影响因子：
4
通讯作者：
Li Xiaohong
中科院分区：
文献类型：
--
作者：
Li Yilei;Jin Tian;Ma Ge;Li Yunchao;Fan Louzhen;Li Xiaohong
在这里，通过用硫脲直接硫化Cd金属有机框架（Cd-MOF-47）原位合成了具有分布在壁（平均厚度为20 nm）中的分级纳米空隙（范围从2 nm至13 nm）的中空CdS纳米盒（平均尺寸为120 nm）。比表面积达到153 m2 g−1。利用所制备的CdS空心纳米盒作为光催化剂，在可见光照射下分解水制氢，其放氢速率高达21 654 μmol g−1 h−1，是体相CdS的近79倍。 这种优异的光催化效率归因于用于改善光吸收性的大比表面积和用于有效利用由于中空框架内的多重散射而产生的激发光的多孔纳米结构。此外，较小的带隙（2.30 eV）与较高的导带（-0.83 V）呈现出强还原性，这有利于将H2O还原为H2。结合荧光光谱（PL）、PL寿命和光电化学技术表明，空心CdS纳米盒比体CdS具有更低的荧光强度、更长的电子寿命和更强的光电流强度，这意味着光生载流子的分离和转移得到了改善。这项工作提出了一种新的方法来制备中空纳米结构，在能量转换领域表现出潜在的应用。
Here, hollow CdS nanoboxes (average size of 120 nm) with graded nanovoids (ranging from 2 nm to 13 nm) distributed in the walls (average thickness of 20 nm) are in situ synthesized through directly sulfurizing a Cd metal–organic framework (Cd-MOF-47) with thiourea. A specific surface area of 153 m2 g−1 is achieved. With as-prepared hollow CdS nanoboxes as photocatalysts for water splitting to H2 (visible light irradiation), H2 evolution rate is as high as 21 654 μmol g−1 h−1, which is nearly 79 times higher than that of bulk CdS. Such an excellent photocatalytic efficiency is ascribed to the large specific surface area for improving light absorbability and the porous nanostructure for efficiently utilizing excitation light due to the multiple scattering within the hollow framework. Moreover, a smaller band gap (2.30 eV) with a higher conduction band (−0.83 V) presents a strong reducibility, which is beneficial for reducing H2O to H2. A combination of fluorescence spectroscopy (PL), PL lifetimes and the photoelectrochemical technique shows that hollow CdS nanoboxes exhibit lower fluorescence intensity, longer electron lifetime and stronger photocurrent intensity than bulk CdS, implying an improved separation and transfer of photoinduced charge carriers. This work presents a novel methodology to prepare hollow nanostructures, exhibiting potential applications in the field of energy conversion.