CdS插层的K_4Nb_(6-x)Cu_xO_(17)复合物的制备及其光催化制氢活性

CdS-intercalated K_4Nb_(6-x)Cu_xO_(17) Composite: Synthesis and Photocatalytic Activity for Hydrogen Production

以Nb2O5,K2CO3和CuO为原料经高温固相反应合成K4Nb6-xCuxO17催化剂,并通过层间离子交换反应,胺插入反应以及硫化反应制备CdS插层K4Nb6-xCuxO17复合催化剂(K4Nb6-xCuxO17/CdS)。利用X射线衍射(XRD),X射线光电子能谱(XPS),场发射扫描电镜(SEM),X射线能谱仪(EDX),紫外-可见漫反射(UV-Vis),分子荧光光谱(PL)等技术对催化剂进行表征。考察了催化剂的可见光催化制氢活性。结果表明,Cu离子掺杂进入K4Nb6O17晶格中,CdS位于K4Nb6O17层间。CdS插层K4Nb6-xCuxO17催化剂的最大吸收光波长约为550 nm。催化剂制氢活性有明显提高,紫外光和可见光下3 h产氢量分别达到279.83 mmol.gcat-1和7.11 mmol.gcat-1。最后讨论了复合催化剂光生电荷转移机理。

Cu doped KaNb6O17 was obtained by a solid reaction with a mixture of Nb2O5, K2CO3 and CuO. The CdS intercalated Cu doped K4Nb6O17 composites （designed as K4Nb6-xCuxO17/CdS） were synthesized via direct cation exchange, alkylamines intercalation and sulfurization process. The products were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）, ultraviolet- visible diffuse reflectance （UV-Vis）, photoluminescence measurement （PL）. The photocatalytic properties of these catalysts for hydrogen production were also investigated. The results reveal that Cu ions enter the crystal lattice of K4Nb6O17, and the CdS is located in the interlayer of K4Nb6O17. The maximum absorption wavelength of CdS intercalated Cu doped K4Nb6O17 composites is about 550 nm. The compound photocatalysts exhibit high activities for photocatalytic hydrogen production under both UV light and visible light irradiation, and the amounts of hydrogen produced are 279.83 mmol·gcat^-1 and 7.11 mmol ·gcat^-1after 3 hours of irradiation, respectively. The mechanism for separation of the photo-generated electrons and holes at the compound photocatalysts are discussed.