摘要：

构建异质结是促进光生载流子分离的有效途径，并可提高半导体光催化材料的光催化活性。采用水热法制备了BiOBr和BiOIO₃，用超声浸渍法制备BiOBr/BiOIO₃复合光催化材料。通过XRD、SEM、TEM、XPS、UV-Vis、FT-IR和PL等表征方法分析了材料的多相结构和化学键。以罗丹明B和环丙沙星为目标污染物，通过降解实验分析光催化材料的活性和降解机理。结果表明：可见光照射60 min后，1.4-BiOBr/BiOIO₃对罗丹明B的降解率，达98%，降解速率常数为0.068 94 min^-1，且5次重复实验后降解率仍可达到85%；可见光照射120 min后，1.4-BiOBr/BiOIO₃对环丙沙星的降解率可达82.6%。以上实验结果可归结为BiOBr/BiOIO₃异质结构在BiOBr和BiOIO₃之间存在协同作用，异质结的形成拓宽了半导体的可见光吸收范围，阻止光生电子-空穴的复合。自由基捕获实验表明O₂^·-和h⁺是降解过程的主要活性物种。提出了BiOBr/BiOIO₃材料光催化降解罗丹明B的可能机理，以期为设计和制备高效、绿色、稳定的光催化剂提供新的途径。

关键词: 光催化, 异质结, 染料废水, 纳米材料

Abstract:

The construction of heterojunction is an effective way to promote the separation of photocarrier and to improve the photocatalytic activity of semiconductor photocatalytic materials. BiOBr and BiOIO₃ were prepared by hydrothermal method， and BiOBr/BiOIO₃ composite photocatalytic materials were prepared by ultrasonic impregnation method. The polyphase structures and chemical bonds of the materials were analyzed by XRD， SEM， TEM， XPS， UV-Vis， FT-IR and PL characterization methods. The activity and degradation mechanism of the photocatalytic materials were analyzed using Rhodamine B and ciprofloxacin as the target pollutants. The results showed that the degradation rate of 1.4-BiOBr/BiOIO₃ was 98% for Rhodamine B after 60 min of visible light irradiation， and the degradation rate constant was 0.068 94 min^-1， and the degradation rate could still reach 85% after five repeated experiments. The degradation rate of ciprofloxacin by 1.4-BiOBr/BiOIO₃ was 82.6% after 120 min of visible light irradiation. The above experimental results can be attributed to the synergistic effect of BiOBr/BiOIO₃ heterostructure between BiOBr and BiOIO₃. The formation of heterojunction broadens the visible light absorption range of the semiconductor and prevents the recombination of electron and holes. The radical capture experiments showed that O₂^·- and h⁺ were the main active species in the degradation process. A possible mechanism for the photocatalytic degradation of Rhodamine B by BiOBr/BiOIO₃ was proposed with a view to provide a new way to design and prepare efficient， green and stable photocatalysts.

Key words: photocatalysis, heterojunction, dye wastewater, nanomaterial

中图分类号: 

• X703