g-C3N4/BiOCl复合光催化剂作为2D/2D异质结用于光催化降解染料性能研究

为扩大BiOCl的太阳光吸收范围，获得更高效的光催化剂，本文通过水热法制备了石墨相氮化碳(g-C₃N₄)/BiOCl (2D/2D)复合光催化剂并对其进行详细表征。结构与形貌表征结果显示BiOCl纳米片沉积在层状g-C₃N₄表面，形成了2D/2D面-面复合结构；光电化学性质分析表明形成的异质结构能有效扩展光吸收频率范围，促进光生载流子分离和迁移，从而有利于光催化性能的提高。以500 W氙灯模拟太阳光源，光催化降解罗丹明B(RhB)的结果表明g-C₃N₄/BiOCl异质结的光催化降解活性远高于单纯的g-C₃N₄和BiOCl。其中9wt%g-C₃N₄/BiOCl表现出了最优越的光催化活性，在180 min内对RhB的降解率为94%，其表观速率常数K_app值为g-C₃N₄和BiOCl的5.7和3.6倍。同时对g-C₃N₄/BiOCl异质结的光催化机制展开研究，结合复合催化剂电子结构和自由基捕获实验提出了在染料敏化作用下RhB的光催化降解机制。 

g-C3N4/BiOCl composite photocatalyst used as 2D/2D heterojunction for photocatalytic degradation of dyes

In order to expand the sunlight absorption range of BiOCl and obtain more efficient photocatalyst, Graphite phase carbon nitride (g-C₃N₄)/BiOCl (2D/2D) composite photocatalyst was prepared by hydrothermal method and characterized in detail. The results of structural and morphology characterization show that BiOCl nanosheets are deposited on the layered g-C₃N₄ surface to form 2D/2D face-face composite structure. The analysis of photoelectric chemical properties shows that the formation of heterostructure can effectively expand the frequency range of light absorption and promote the separation and migration of photocarriers, which is conducive to the improvement of photocatalytic performance. The results of photocatalytic degradation of RhB by xenon lamp (500 W) show that the photocatalytic degradation activity of g-C₃N₄/BiOCl heterojunction is much higher than that of g-C₃N₄ and BiOCl alone. Among them, 9wt%g-C₃N₄/BiOCl shows the most superior photocatalytic activity, and the degradation rate of RhB is 94% within 180 min, and the apparent rate constant K_app value of 9wt%g-C₃N₄/BiOCl is 5.7 and 3.6 times that of g-C₃N₄ and BiOCl. At the same time, the photocatalytic mechanism of g-C₃N₄/BiOCl heterojunction was studied, and the photocatalytic degradation mechanism of RhB under dye sensitization was proposed by combining the electronic structure of the composite catalyst and free radical capture experiment.