高分散的CoWO4或CuWO4提高WO3的光催化性能

本文采用原位浸渍与固相反应结合，成功地合成了CoWO4或CuWO4高度分散在WO3表面的复合CoWO4/WO3或CuWO4/WO3光催化剂。通过XRD，SEM，TEM，EDS，HR-TEM，UV-vis DRS，SPV和活性物种实验研究了CoWO4/WO3和CuWO4/WO3样品的结构，形貌，光物理性质和光催化降解机理。XRD，SEM和TEM结果表明，当CoWO4或CuWO4的负载量较小时，CoWO4或CuWO4高度分散在WO3表面上。但是当CoWO4或CuWO4的负载量增加时，WO3表面的CoWO4或CuWO4颗粒发生明显的团聚。可见光光催化降解RhB的实验结果表明，所有CoWO4/WO3或CuWO4/WO3样品的光催化活性都优于WO3的活性。这主要是因为WO3和CoWO4或CuWO4之间形成的II型异质结能够显著促进光生电子和空穴的分离。此外，CoWO4/WO3和CuWO4/WO3系列样品中，0.2％CoWO4/WO3和0.2％CuWO4/WO3分别显示了最优异的光催化活性，与WO3相比，其光催化活性分别提高了约9.1倍和6.8倍。此外，活性物种实验表明，光催化过程中在0.2％CoWO4/WO3和0.2％CuWO4/WO3催化剂上产生的?OH，h+和?O2?都是光催化降解RhB的活性物种。本文为设计高活性的光催化剂提供了一种思路。

Boosting the Photocatalytic Activity of WO_3 by Highly Dispersed CoWO_4 or CuWO_4

WO3 photocatalyst decorated with highly dispersed CoWO4 or CuWO4 nanoparticles (CoWO4/WO3 or CuWO4/WO3) was successfully synthesized using an in-situ impregnation method followed by solid-state reaction. The structure, morphology, photophysical property, and photocatalytic degradation mechanism of the CoWO4/WO3 or CuWO4/WO3 sample were investigated by XRD, SEM, TEM, EDS, HR-TEM, UV-vis DRS, SPV, and active trapping techniques. XRD, SEM, and TEM results presented that CoWO4 or CuWO4 are highly dispersed on the WO3 surface when the loading amount of CoWO4 or CuWO4 is small. However, obvious agglomeration is observed for the CoWO4 or CuWO4 particles when the loading amount of CoWO4 or CuWO4 was increased. The visible-light photocatalytic degradation of RhB result shows that all CoWO4/WO3 or CuWO4/WO3 samples exhibit superior photocatalytic performance than pure WO3. This is mainly because that the formation of type II heterojunction between WO3 and CoWO4 or CuWO4, which promote the photogenerated electrons and holes separation and transfer. Moreover, it is found that 0.2% CoWO4/WO3 or 0.2% CuWO4/WO3, in which MWO4 nanoparticles are uniformly dispersed on the surface of WO3 shows the most excellent photocatalytic activity among CoWO4/WO3 or CuWO4/WO3 samples, respectively. As compared with WO3, an enhancement about 9.1 times or 6.8 times in photocatalytic activity is observed on 0.2% CoWO4/WO3 or 0.2% CuWO4/WO3, respectively. Furthermore, active species trapping experiment demonstrates that ?OH, h+, and ?O2? generated during the photocatalytic process are all the reactive species in photocatalytic degradation of RhB on CoWO4/WO3 or CuWO4/WO3. This study presents a strategy to design superior photocatalyst for organic compound degradation.