高活性光催化剂纳米Ag-碳纳米管-混晶TiO_2复合纤维的可控制备

Toward a high-activity photocatalyst via controllable synthesis of nano Ag-carbon nanotube-mixed crystal TiO_2 composite fibers

为解决TiO_2对太阳能有效利用率低、光生电子与空穴再复合率高、光催化活性低且难回收等应用难题,利用静电纺丝技术成功地制备了纳米Ag-碳纳米管(CNT)-混晶TiO_2复合纤维,并采用SEM、XRD、EDS及Raman等表征方法详细分析了材料的微观结构与组分,研究了纳米Ag-CNT-混晶TiO_2复合纤维对亚甲基蓝的光催化活性。结果表明:锐钛矿与金红石相TiO_2混晶不仅可降低材料的禁带宽度,还能减缓光生电子与空穴的复合淬灭;纳米Ag颗粒的局域表面等离激元共振可增强Ag-CNT-混晶TiO_2复合纤维的光吸收,CNT能促进光生电子与空穴的有效分离;纳米Ag-CNT-混晶TiO_2复合纤维对亚甲基蓝的首次降解率可达97.5%,且5次催化循环后对亚甲基蓝的降解率仍保持在90.0%以上。所得结论表明静电纺丝制备的新型纳米Ag-CNT-混晶TiO_2复合纤维是一种高活性的光催化剂,且容易回收,具有光降解亚甲基蓝的应用前景。

In order to solve the application problems of TiO2 such as the poor effective utilization rate for solar energy,high recombination rate of photoinduced electrons and holes,low photocatalytic activity and difficulty in recycle etc.,nano Ag-carbon nanotube（CNT）-mixed crystal TiO2 composite fibers were synthesized successfully by electrospinning technology,and the microstructures and constructions of the materials were analyzed in detail by characterization methods such as SEM,XRD,EDS and Raman etc.,thus the photocatalytic activities of nano AgCNT-mixed crystal TiO2 composite fibers for methylene blue were investigated.The results show that the mixed crystal of anatase-and rutile-TiO2 can not only reduce the band gap,but also slow down the combination and cancellation of photoinduced electrons and holes.The localized surface plasmon resonance of Ag nanoparticles can enhance the light absorption of nano Ag-CNT-mixed crystal TiO2 composite fibers,and CNT can promote the effective segregation of photoinduced electrons and holes.The degradation rate of nano Ag-CNT-mixed crystal TiO2 composite fibers for methylene blue in the first cycle reaches 97.5%,and the degradation rate for methylene blue after 5catalytic cycles still retains above 90.0%.The conclusions obtained show that the new type nano Ag-CNT-mixed crystal TiO2 composite fiber prepared by electrospinning is a high-activity photocatalyst and is easy to be recycled,which has application prospects for the photo degradation of methylene blue.