Two-dimensional polyimide heterojunctions for the efficient removal of environmental pollutants under visible-light irradiation
Two-dimensional polyimide heterojunctions for the efficient removal of environmental pollutants under visible-light irradiation
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二维聚酰亚胺异质结在可见光照射下高效去除环境污染物
DOI：
10.1039/c9cp03471d
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发表时间：
2019
影响因子：
3.3
通讯作者：
Ho Wingkei
中科院分区：
文献类型：
--
作者：
Wang Xin;Zhao Xinyu;Zhao Yingnan;Tan Hua Qiao;Du Zhilu;Shang Qingkun;Qiu Tianyu;Ho Wingkei
具有大界面接触和紧密界面电荷转移的二维异质材料被认为是构建高效光催化剂的理想模型。然而，很少有研究报道这些二维异质结。在此，我们报告了一系列新的二维异质结包括聚酰亚胺（PI）和苝-3，4，9，10-四羧酸二酐（TD）。这些异质结，表示为PI-TDx（其中x表示添加的TD的量，即，x = 0.13、0.18、0.27、0.54和1.08 g），通过三聚氰胺（MA）、均苯四酸二酐（PD）和不同量的TD的固相热共聚合制备。利用红外光谱、X射线衍射、X射线光电子能谱和透射电子显微镜分析了二维异质结结构。光催化实验表明，在可见光照射下，PI-TDx对有机染料罗丹明B（RhB）和甲基紫（MV）的光催化降解以及Cr（VI）的光催化还原均表现出优异且稳定的光催化性能。其中，PI-TD 0. 18的光催化性能最好。其降解RhB的活性分别是单独的PIMP（由MA和PD形成）和PIMT（由MA和TD形成）的2.7倍和7.5倍。值得注意的是，PI-TD 0. 18在600 nm的光照射下保持一定的光催化活性。光催化机理研究表明，PI-TD 0. 18具有典型的II型异质结结构。其二维异质结结构大大增强了复合材料的可见光吸收，有效抑制了光生载流子的辐射复合，从而提高了复合材料的电荷转移和分离能力，提供了优异的光催化性能。本工作为设计和构建新型高效二维有机共轭聚合物光催化剂提供了重要参考。
Two-dimensional (2D) heteromaterials with large interface contact and intimate interfacial charge transition have been considered to be an ideal model for constructing highly efficient photocatalysts. However, few studies have reported on these 2D heterojunctions. Herein, we report a series of new 2D heterojunctions comprising polyimide (PI) and perylene-3,4,9,10-tetracarboxylic dianhydride (TD). These heterojunctions, denoted as PI–TDx (where x represents the amount of TD added, i.e., x = 0.13, 0.18, 0.27, 0.54, and 1.08 g), were prepared by the solid thermal copolymerization of melamine (MA), pyromellitic dianhydride (PD), and different amounts of TD. FT-IR spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy analyses were used to verify the 2D heterojunction structure. Photocatalytic experiments reveal that PI–TDx exhibit excellent and stable photocatalytic performance for the degradation of the organic dyes rhodamine B (RhB) and methyl violet (MV), as well as for the photoreduction of Cr(VI), under visible-light irradiation. Among the samples, PI–TD0.18 exhibits the best photocatalytic performance. Its activity is about 2.7 times and 7.5 times higher than that of individual PIMP (formed by MA and PD) and PIMT (formed by MA and TD) for RhB degradation, respectively. Notably, PI–TD0.18 retains a certain photocatalytic activity under light irradiation at 600 nm. The photocatalytic-mechanism study demonstrates that PI–TD0.18 has a classic type-II heterojunction. Its 2D heterojunction greatly enhances the visible-light absorption of the composites and effectively suppresses the radiation recombination of photogenerated carriers, thereby improving its charge transfer and separation abilities and providing excellent photocatalytic performance. This work may serve as an important reference for the design and construction of new highly efficient 2D organic conjugated-polymer photocatalysts.