Preparation of BiVO₄/g-C₃N₄-porous functional ceramics and their photocatalytic properties
BiVO₄/g-C₃N₄-多孔功能陶瓷的制备及其光催化性能的研究

摘要

本文采用简单的实验方法制备了BiVO₄/g-C₃N₄-多孔功能陶瓷复合光催化剂；通过XRD、SEM 、紫外-可见漫反射等对其物质组成和结构形貌等进行表征测试，XRD表征显示，BiVO₄在2θ为18°、28°、30°、50°处出现特征峰（对应晶面101、112、004、220），与标准卡片PDF#83-1697吻合；g-C₃N₄在2θ为13°、27°处出现典型特征峰，BiVO₄/g-C₃N₄复合物同时呈现两者特征峰，证明复合成功；SEM观察到BiVO₄为片状与不规则棒状结构，g-C₃N₄为不规则片状，复合后g-C₃N₄分散性提升，形成不规则棒状结构，表征结果均与预期效果一致；将BiVO4对g-C3N4进行修饰，制备不同比例的BiVO₄/g-C₃N₄复合物，并在可见光照射下降解一定浓度的MB溶液以探究其最佳修饰量，结果表明10% BiVO₄/ g-C₃N₄的降解效率最佳，降解效率为89.55%；另外，通过对四环素的降解实验证明BiVO₄/g-C₃N₄具有广泛的催化性能；然后将BiVO₄/g-C₃N₄负载到多孔功能陶瓷的表面并探究最佳负载量，最佳负载量为15%，降解效率为67.31%；最后结合各类表征和测试结果对复合光催化剂在降解过程中的电荷转移机制进行了初步探索。

Abstract

The BiVO₄/g-C₃N₄/porous functional ceramic composite photocatalyst was prepared via a simple experimental method. Its chemical composition, structure and morphology were characterized by XRD, SEM and UV-Vis diffuse reflectance spectroscopy. XRD characterization shows that BiVO₄ exhibits characteristic peaks at 18°, 28°, 30° and 50°(2θ), corresponding to the crystal planes (101), (112), (004) and (220), which match well with the standard card PDF#83-1697. g-C₃N₄ presents typical characteristic peaks at 13° and 27°(2θ). The BiVO₄/g-C₃N₄ composite shows characteristic peaks of both components, which proves successful compounding. SEM observations reveal that BiVO₄ has sheet and irregular rod-like structures, while g-C₃N₄ has an irregular sheet structure. After compounding, the dispersibility of g-C₃N₄ is improved, forming irregular rod-like structures, and all characterization results are consistent with the expected effects.BiVO₄ was used to modify g-C₃N₄ for preparing BiVO₄/g-C₃N₄ composites with different mass ratios. The optimal modification amount was investigated by degrading a certain concentration of MB solution under visible light irradiation.
Results show that the 10% BiVO₄/g-C₃N₄ composite achieves the highest degradation efficiency of 89.55%. In addition, the tetracycline degradation experiment proves that BiVO₄/g-C₃N₄ has broad catalytic performance. Then, BiVO₄/g-C₃N₄ was loaded onto the surface of porous functional ceramic to explore the optimal loading amount. The optimal loading amount is 15%, with a degradation efficiency of 67.31%. Finally, the charge transfer mechanism of the composite photocatalyst during degradation was preliminarily explored based on various characterization and test results.