Bi_(2)WO_(6)/g-C_(3)N_(4)复合光催化剂的制备及其光催化性能研究

Preparation of Bi_(2)WO_(6)/g⁃C_(3)N_(4)composite photocatalyst and its photocatalytic property

以尿素、硝酸铋、钨酸钠等为主要原料,在热缩聚法制备g-C_(3)N_(4)的基础上,通过水热法制备Bi_(2)WO_(6)/g-C_(3)N_(4)复合光催化剂。在模拟太阳光照射下,研究Bi_(2)WO_(6)/g-C_(3)N_(4)复合光催化剂对甲基橙的光催化降解性能。结果表明,复合光催化剂相比于单体光催化剂的性能有显著提高。在Bi_(2)WO_(6)与g-C_(3)N_(4)质量比为2∶1、水热温度为180℃、水热时间为12 h条件下,复合光催化剂的性能最好。光照时间210 min时,甲基橙降解率达到了98.15%,相比于单体Bi_(2)WO_(6)和g-C_(3)N_(4)光催化剂的效率分别提高了25.1%和37.7%,且光催化降解过程符合一级动力学方程。复合光催化剂具有优异的稳定性,经过4次重复性实验,甲基橙降解率仍达到95.17%。

Taking urea,Bi(NO3)3·5H2O and Na2WO4·2H2O as the main raw materials,g⁃C_(3)N_(4)is prepared through the thermal polycondensation method and used in preparing Bi_(2)WO_(6)/g⁃C_(3)N_(4)composite photocatalysts through the hydrothermal method.The photocatalytic efficacy of the specimens is evaluated through the degradation of methyl orange under the radiation of simulated sunlight.It is shown that the composite photocatalysts show much higher photocatalytic performance than monomeric photocatalysts.The composite photocatalyst exhibits the best photocatalytic performance when it is prepared under the conditions that the mass ratio of Bi_(2)WO_(6)/g⁃C_(3)N_(4)is 2∶1,the hydrothermal temperature is 180℃and hydrothermal time is 12 h.The degradation of methyl orange reaches 98.15%with 210 min of radiation time over this photocatalyst,representing 25.1%and 37.7%higher than those over Bi_(2)WO_(6)alone and g⁃C_(3)N_(4)alone,respectively.The photocatalytic degradation process accords with the first order kinetic equation.The degradation rate of methyl orange still reaches 95.17%after four repeated experiments over the composite photocatalyst,showing an excellent stability.