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以胶态二氧化硅(SiO_2)为模板,单氰胺(CH_2N_2)为前驱体制备了高效可见光催化活性的介孔石墨相氮化碳(mpg-C_3N_4)。采用X-射线衍射(XRD)、热重分析(TGA)、透射电镜(TEM)、红外光谱(FT-IR)、比表面积测试(BET)和紫外-可见光谱(UV-vis)等测试手段对其物理化学特性及形貌结构进行了表征和分析。TEM结果表明,前驱体单氰胺反向复制了胶态二氧化硅模板,mpg-C_3N_4具有介孔结构;BET结果表明,mpg-C_3N_4的比表面积(36~94 m~2/g)和孔容(0.13~0.35m~3/g)可根据模板的加入量进行调节。光催化降解实验表明,mpg-C_3N_4的催化效果明显优于直接煅烧前驱体制备的氮化碳(bulk g-C_3N_4)。且煅烧温度550℃,恒温时间4h,SiO_2和CH_2N_2质量比为1.2时制备的mpg-C_3N_4光催化活性最高,2.5h对甲基橙降解率接近100%。催化机理分析实验表明,mpg-C_3N_4光催化降解甲基橙过程中(h+)和(·O-2)起主要作用,而(·OH)作用较小。
Mesoporous graphite carbon nitride (mpg-C_3N_4) with high visible light photocatalytic activity was prepared by using colloidal silica (SiO_2) as template and melamine (CH_2N_2) as precursor. (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), infrared spectroscopy (FT-IR), BET and UV- Its physical and chemical characteristics and morphology were characterized and analyzed. TEM results showed that the precursor of monocylamine replicated colloidal silica template and mpg-C_3N_4 had mesoporous structure. The BET results showed that the specific surface area of mpg-C_3N_4 (36 ~ 94 m ~ 2 / g) Capacity (0.13 ~ 0.35m ~ 3 / g) can be adjusted according to the amount of template added. Photocatalytic degradation experiments showed that the catalytic effect of mpg-C_3N_4 was significantly better than that of the bulk g-C_3N_4 prepared by direct calcination. The photocatalytic activity of mpg-C_3N_4 was the highest when the mass ratio of SiO_2 and CH_2N_2 was 1.2, and the degradation rate of methyl orange was close to 100% after 2.5h. Catalytic mechanism analysis showed that (h +) and (· O-2) played a major role in the photocatalytic degradation of methyl orange in mpg-C_3N_4, while (· OH) had little effect.