苝四羧酸二酰亚胺修饰增强g-C_(3)N_(4)光催化性能

Perylene tetracarboxylic bisimide decorated g-C_(3)N_(4) with enhanced photocatalytic activity

以3,4,9,10-苝四甲酸二酐和L-天冬氨酸为原料,合成水溶性苝二酰亚胺衍生物N,N′-二(2-丁二酸基)-3,4,9,10-苝四羧酸二酰亚胺(PASP)。采用水热法将PASP接枝在g-C_(3)N_(4)上,制备PASP改性g-C_(3)N_(4)复合光催化剂(g-C_(3)N_(4)-PASP)。通过X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见光漫反射光谱(UV-Vis DRS)和固体荧光光谱等对g-C_(3)N_(4)-PASP的组成、结构、形貌和光学性质等进行表征,考察g-C_(3)N_(4)-PASP对水溶液中模型污染物亚甲基蓝(MB)的光催化降解活性。结果表明:g-C_(3)N_(4)与PASP经水热反应,可通过酰胺键共价结合;相比纯g-C_(3)N_(4),g-C_(3)N_(4)-PASP比表面积显著增大,吸收带边红移至614 nm,同时PASP修饰可促进g-C_(3)N_(4)材料表面光生电子和空穴分离,进而有效提升光催化活性。在可见光(λ>420 nm)照射下,g-C_(3)N_(4)-PASP对MB的降解率60 min内可达99.4%,降解速率常数k约为g-C_(3)N_(4)的2倍。

A water-soluble perylene bisimide derivative,N,N′-di(2-succinic acid)-perylene-3,4,9,10-tetracarboxylic bisimide(PASP)was synthesized by using 3,4,9,10-perylenetetracarboxylic dianhydride and L-aspartic acid as starting materials.The PASP were grafted onto graphitic carbon nitride(g-C_(3)N_(4))via hydrothermal method to prepare PASP modified g-C_(3)N_(4)hybrid photocatalyst(g-C_(3)N_(4)-PASP).The composition,structure,morphology and optical properties of the prepared g-C_(3)N_(4)-PASP samples were typically characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),transmission electron microscopy(TEM),UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS),and solid-state fluorescence spectroscopy.In addition,the photocatalytic activities of the prepared g-C_(3)N_(4)-PASP photocatalysts were evaluated by decomposition of methylene blue(MB)pollutant in water solution under visible light.The results reveal that PASP can be facilely linked to the g-C_(3)N_(4)covalently via amide bond by hydrothermal treatment;compared to pristine g-C_(3)N_(4),the g-C_(3)N_(4)-PASP possesses obviously higher specific surface area,dramatic red shifted absorption edge of 614 nm,and more efficient charge separation.Therefore,the visible light photo-catalytic degradation of MB pollution in water over the g-C_(3)N_(4)-PASP is notably improved.The g-C_(3)N_(4)-PASP could degrade 99.4%of MB dyes in 60 min under visible light irradiations(λ>420 nm),with a pseudo-first-order rate constant 2 times higher than that of pristine g-C_(3)N_(4).