TiO2/Ag2 NCN复合光催化剂的制备与可见光催化性能

摘要

TiO2/Ag2 NCN composite catalysts were fabricated through the precipitation of silver salt and cya-namide in the presence of TiO2 nanoparticles. X-ray diffraction( XRD) , scanning electron microscopy( SEM) , Fourier transform infrared spectroscopy ( FTIR ) and Ultraviolet-visible ( UV-Vis ) spectoscopy were used to characterize the composites. The results showed that the heterojunction structure was obtained by depositing TiO2 nanoparticles on the surface of Ag2 NCN through weak physical interaction. The UV-Vis absorption peak of TiO2/Ag2 NCN shift toward long wavelength and the energy gap narrow down in comparison with that of pure Ag2 NCN. The degradation of methylene blue( MB) catalyzed by the samples under visible-light irradiation was investigated and enhanced photocatalytic activity was observed for TiO2/Ag2 NCN composite particles. The energy band structure of composite particles demonstrates that the presence of TiO2 promote the separation of photogenerated electron and hole, and as a result, improves the photocatalytic activity.%利用银盐与单氰胺水溶液的沉淀反应，通过共混不同质量分数的纳米TiO2粒子制备了TiO2/Ag2 NCN复合光催化剂。使用X射线衍射仪( XRD)、扫描电子显微镜( SEM)、傅里叶变换红外( FTIR)光谱仪和紫外-可见( UV-Vis)吸收光谱仪对复合光催化剂的结构进行了表征。结果表明，锐钛矿相TiO2纳米颗粒沉积在Ag2 NCN表面形成异质结构，二者间以弱的物理作用力相结合。 TiO2的掺杂使得复合颗粒的UV-Vis吸收光谱发生红移，带隙变窄。以亚甲基蓝( MB)为光催化降解对象，研究了TiO2/Ag2 NCN复合颗粒的可见光催化活性。结果表明，与单一Ag2 NCN相比，复合颗粒表现出增强的光催化性能。对TiO2/Ag2 NCN复合颗粒的光催化反应动力学过程及光催化机理进行了探讨。