SiC/C3N4复合材料的光催化降解亚甲基蓝性能研究

Photocatalytic degradation of methylene blue by SiC/C3N4 composite

采用冷却结晶法制备不同配比的SiC与三聚氰胺前驱体,煅烧后得到SiC/C 3N 4复合材料,研究了在白炽灯照射下复合材料对亚甲基蓝的光催化降解性能。结果表明,SiCN100型SiC/C 3N 4复合材料的光催化降解能力最强,光照150 min时亚甲基蓝的降解率达到76%,光降解反应速率常数为0.00757 min^-1,是纯SiC的6倍,且该催化剂在循环测试中性能稳定。采用X-射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外可见-漫反射光谱(UV-Vis DRS)和光致发光光谱(PL)表征了SiC/C 3N 4复合材料,并通过活性基团捕获实验,深入分析了亚甲基蓝的光催化降解机理,发现电子在降解过程中起最关键的作用,活性基团对降解率的影响程度依次为e->h^+>·O2^-。

SiC/C 3N 4 composites were obtained by calcining the precursor prepared by cooling crystallization method,and the photocatalytic degradation efficiencies of methylene blue were studied by the composites under incandescent lamp.The results showed that SiCN100 composite has the strongest photocatalytic ability,and the degradation efficiency of methylene blue reached 76%for 150 min irradiation.The photo-degradation rate constant of methylene blue was 0.00757 min-1 over SiCN100,which was 6 times higher than that over pure SiC.The photocatalytic performance of the SiCN100 is stable in the cyclic test.SiC/C 3N 4 composites were characterized using X-ray diffraction(XRD),scanning electron microscope(SEM),transmission electron microscopy(TEM),UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS),photoluminescence spectra(PL)and the photocatalytic degradation mechanism of methylene blue was analyzed in detail.The radicals trapping experiments revealed that electrons play an important role in the MB degradation.