CeO_(2)/g-C_(3)N_(4)复合光催化剂的制备及其性能研究

Study on the Preparation and Performance of CeO_(2)/g-C_(3)N_(4) Composite Photocatalyst

采用高温聚合有机物前驱体的方法,以三聚氰胺为前驱体,制得类石墨型氮化碳(g-C_(3)N_(4))粉末,采用水热法制得CeO_(2)/g-C_(3)N_(4)复合光催化剂,对其进行了表征,考察了CeO_(2)/g-C_(3)N_(4)复合光催化剂在可见光下处理亚甲基蓝的性能,并对CeO_(2)/g-C_(3)N_(4)复合光催化剂进行回收实验、吸附实验以及光催化动力学分析。结果表明,CeO_(2)/g-C_(3)N_(4)中g-C_(3)N_(4)和CeO_(2)分别为石墨相和萤石相,复合CeO2使得g-C_(3)N_(4)的吸附性能有了大的提高,15 min能达到吸附平衡,吸附82.5%的亚甲基蓝;45 min后对亚甲基蓝处理率达到99.45%,远远快于g-C_(3)N_(4)。CeO_(2)/g-C_(3)N_(4)在5次使用后仍然可以保持73.1%的净化效果。亚甲基蓝处理过程包括吸附和光解2部分,光解反应符合一级动力学方程。

The method of polymerizing organic precursors at high temperature was used with melamine as the precursor to prepare graphite-like carbon nitride(g-C_(3)N_(4)) powder.The CeO_(2)/g-C_(3)N_(4) composite photocatalyst was prepared by hydrothermal method.All synthetics were characterized.The treatment performance of the CeO_(2)/g-C_(3)N_(4) composite photocatalyst on the degradation of methylene blue under visible light was investigated,and the recovery experiment,adsorption experiment and kinetic analysis of CeO_(2)/g-C_(3)N_(4) composite photocatalyst were carried out.The results showed that,in CeO_(2)/g-C_(3)N_(4),g-C_(3)N_(4) and CeO_(2) were graphite phase and fluorite phase,respectively.The composite CeO2 greatly improves the adsorption performance of g-C_(3)N_(4).The adsorption equilibrium could be reached in 15 min,and 82.5% of methylene blue could be adsorbed.The treatment rate of methylene blue reached 99.45% by CeO_(2)/g-C_(3)N_(4) after 45 min,which was much faster than the rate by g-C_(3)N_(4).CeO_(2)/g-C_(3)N_(4) could still maintain 73.1% purification effect after five times of reuse.The treatment process of methylene blue by CeO_(2)/g-C_(3)N_(4) included adsorption and photolysis,and the photolysis reaction conformed to the first-order kinetic equation.