Bandgap engineering of NiWO4/CdS solid Z-scheme system via an ion-exchange reaction
Bandgap engineering of NiWO4/CdS solid Z-scheme system via an ion-exchange reaction
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DOI：
10.1016/j.apcatb.2018.09.050
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发表时间：
2019-02
期刊：
影响因子：
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通讯作者：
Mingjie Li;S. Yokoyama;Hideyuki Takahashi;K. Tohji
中科院分区：
文献类型：
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作者：
Mingjie Li;S. Yokoyama;Hideyuki Takahashi;K. Tohji
能带对齐对于固体Z-计划系统（SZSS）中的有效电荷转移和太阳光利用是必不可少的。在这里，我们提出了一种策略，通过NiWO 4前体和Cd 2 +/S2-之间的离子交换反应，这是证实了SEM-EDS和拉曼光谱制备的NiWO 4/CdS组合物作为SZSS与一个额外的功能的可调带隙。紫外可见漫反射光谱和光致发光光谱确定了带隙结构。光系统II由NiWO 4构成，而光系统I（PSI）的结构取决于组合物中的S含量。随着S含量从0增加到45at%，PSI的带隙从2.62减小到1.86 eV。此外，光致发光光谱和光催化H2产生实验表明，S的引入提供了适当的能带排列，有效的电荷转移和H2产生。通过调整NiWO 4/CdS复合物中S含量的SZSS带隙工程也可以扩展到其他金属钨酸盐和金属硫化物复合物（MWO 4/MS）。
Energy band alignment is essential for efficient charge transfer and solar light utilization in the solid Z-scheme system (SZSS). Here, we propose a strategy to fabricate the NiWO4/CdS composition as SZSS with an additional feature of a tunable bandgap via an ion-exchange reaction between the NiWO4precursor and Cd2+/S2–, which is confirmed with SEM-EDS and Raman spectroscopy. UV–vis DRS and photoluminescence spectrometry determine the bandgap structures. Photosystem II is constructed from NiWO4, while the structure of photosystem I (PSI) depends on the S content in the composition. As the S content increases from 0 to 45 at%, the bandgap decreases from 2.62 to 1.86 eV for PSI. Moreover, the photoluminescence spectra and photocatalytic H2generation experiments demonstrate that the introduction of S provides the proper band alignment for efficient charge transfer and H2generation. Bandgap engineering in SZSS by adjusting the S content in the NiWO4/CdS composition can be also extended to other metal tungstate and metal sulfide composites (MWO4/MS).