采用机械混合/热处理的方法制备了具有异质结结构的Bi₄Ti₃O₁₂/g-C₃N₄复合光催化剂，利用XRD、SEM及UV-Vis对所制备的复合光催化剂的结构与形貌进行了表征。结果表明，复合光催化剂中形成了异质结构，其禁带宽度减小，吸收带边红移，可见光吸收增加。以RhB为目标污染物评价复合光催化剂的活性，考察了不同g-C₃N₄复合量对光催化剂反应活性的影响。结果表明，异质结型复合光催化剂的光催化活性明显优于单相Bi₄Ti₃O₁₂；当g-C₃N₄的质量分数为20%时，其光催化性能最佳（90 min达92.8%），其表观反应常数为单相Bi₄Ti₃O₁₂的4倍。复合光催化剂光催化活性提高的原因是Bi₄Ti₃O₁₂与g-C₃N₄之间形成了异质结，显著降低了光生电子和空穴的复合几率。外加捕获剂的实验结果表明，复合光催化剂的主要活性基团为空穴（h⁺）与超氧自由基（·O^2-）。

Bi₄Ti₃O₁₂/g-C₃N₄ composite photocatalysts are prepared by a mechanical mixing/heat treatment method.The structure and morphology of as-prepared Bi₄Ti₃O₁₂/g-C₃N₄ are characterized by XRD,SEM and UV-Vis.The results indicate that heterojunction structure is formed in Bi₄Ti₃O₁₂/g-C₃N₄,thus decreasing the band gap of Bi₄Ti₃O₁₂,red-shifting the absorption band edge,and enhancing the absorption of visible light.The photocatalytic activity is evaluated through the degradation of RhB solution under visible light irradiation and the influences of the amount of g-C₃N₄ on the reactive activity of the photocatalysts are researched.Compared with the single-phase Bi₄Ti₃O₁₂,Bi₄Ti₃O₁₂/g-C₃N₄ composite photocatalysts with a heterojunction structure exhibits better photocatalytic performance.It is found that Bi₄Ti₃O₁₂/g-C₃N₄ photocatalyst with 20% of g-C₃N₄ exhibits the best photocatalytic activity,reaching 92.8% in 90 min,and its apparent reaction constant is about 4 times that of single-phase Bi₄Ti₃O₁₂.Higher photocatalytic activity can be ascribed to the formation of a heterojunction between Bi₄Ti₃O₁₂ and g-C₃N₄,which markedly suppresses the recombination of photogenerated electron-hole pairs.Analysis on the radical scavengers experiment results confirms that h⁺ and.O^2- are the primary reactive species for the photocatalysis process.

张根(1994-),男,硕士研究生,主要从事光催化方面的研究,wust022029@163.com