【摘要】 本文制备了p-n复合半导体光催化剂CaFe₂O₄/TiO₂,采用X线衍射仪（XRD）、扫描电子显微镜（SEM）、紫外-可见漫反射光谱仪（UV-Vis DRS）及电化学工作站对光催化剂的结构和性能进行表征。以模拟太阳光催化产氢速率评价p-n复合半导体光催化剂CaFe₂O₄/TiO₂的光催化活性。探讨光催化剂中CaFe₂O₄添加量、甲醛浓度、反应体系pH对光催化产氢性能的影响,并对光催化活性的提高进行了机制分析。结果表明:CaFe₂O₄的导带比TiO₂的导带更负,同时在CaFe₂O₄/TiO₂内存在内建电场,两者均促进了电子从CaFe₂O₄向TiO₂的迁移,增强了光催化活性,0.4%CaFe₂O₄/TiO₂具有最高的光催化活性,2 h内的产氢速率达到0.989 mmol/（g·h）。此外,CaFe₂O₄/TiO₂的稳定性较好,可多次循环使用。更多还原

【Abstract】 A series of p-n coupled CaFe₂O₄/TiO₂ photocatalysts were prepared. The structure and properties of CaFe₂O₄/TiO₂ catalysts were characterized by X-ray diffraction（XRD）,scanning electron microscope（SEM）,ultraviolet-visible diffuse reflectance spectrum（UV-Vis DRS）and electrochemical tests. The photocatalytic activities of CaFe₂O₄/TiO₂ catalysts were evaluated by photocatalytic hydrogen production under solar light. The effects of the amount of CaFe₂O₄,the concentration of HCHO and pH on hydrogen production were investigated. The mechanism of photocatalytic activity was discussed. Results showed that CaFe₂O₄/TiO₂ exhibited higher photocatalytic activity attributed to electrons transferring from CaFe₂O₄ to TiO₂,resulted from the more negative conduction band potential of CaFe₂O₄ than TiO₂ and the inner electric field. 0. 4%CaFe₂O₄/TiO₂ had the best performance among the various CaFe₂O₄/TiO₂ composite powders tested,with a hydrogen evolution rate of up to 0. 989 mmol /（g · h）in 2 h,and CaFe₂O₄/TiO₂ also exhibited the good stability with several recycling times.更多还原