【摘要】 石墨相氮化碳（g-C₃N₄）因制备成本低、无毒无害、物化性能稳定等优点而备受关注,然而,不同前驱体制得的g-C₃N₄的产率和光催化活性也不同。分别以尿素、二氰胺、三聚氰胺为前驱体,采用热剥离法制备了氮化碳2D纳米片。系统考察了不同前驱体及热剥离温度对氮化碳结构和光催化性能的影响。结果表明,以尿素为前驱体不经热剥离可以直接制得光催化性能优异的g-C₃N₄2D纳米片,其对亚甲基蓝的降解率最高,为60%,但其产率极低,约2%～3%。以二氰胺和三聚氰胺为前驱体制得的氮化碳再经热剥离处理可得到结构疏松、光催化性能优异的2D g-C₃N₄纳米薄片,其产率可分别高达32.5%和36.8%。其中,以双氰胺为前驱体在580℃处理4 h后制得的2D纳米薄片g-C₃N₄光催化活性最优,其对亚甲基蓝的降解效率可达91.1%,较未剥离样品提高了40%。经4次循环使用后,其降解率仍可保持在90%,表现出良好的稳定性和重复实用性。更多还原

【Abstract】 Graphite carbon nitride（g-C₃N₄） has attracted much attention due to its advantages such as low preparation cost, non-toxic and harmless, and stable physicochemical properties. However, the yield and photocatalytic activity of g-C₃N₄ obtained from different precursor systems are also different. In this study, urea, dicyanamide, and melamine were used as precursors to prepare carbon nitride 2 D nanosheets by thermal stripping method, respectively. The effects of different precursors and thermal exfoliation temperature on the structure and photocatalytic performance of carbon nitride were systematically investigated. The results show that g-C₃N₄ 2 D nanosheets with excellent photocatalytic performance can be directly prepared with urea as the precursor without thermal exfoliation, and the degradation rate of methylene blue is the highest, which is 60%. But its yield is extremely low, about 2%-3%. Carbon nitride prepared with dicyandiamide and melamine as precursors can be subjected to thermal exfoliation treatment to obtain 2 D g-C₃N₄ nanosheets with a loose structure and excellent photocatalytic performance. The yields can be as high as 32.5% and 36.8%, respectively. Among them, the 2 D nanosheets g-C₃N₄ prepared with dicyandiamide as a precursor treated at 580 ℃ for 4 hours exhibited the best photocatalytic activity, and its degradation efficiency of methylene blue can reach 91.1%, which is 40% higher than that of the unexfoliated sample. After 4 cycles of use, the degradation rate can still be maintained at 90%, showing good stability and repeatability.更多还原