有机光敏剂功能化石墨烯的制备、电子传递和光催化作用

Sensitizers functionalized graphene/metal nanoparticle composites will be prepared by bonding porphyrin-, phthalocyanine- and tris(2,2'-bipyridyl)ruthenium molecules chemically on the two-dimensional plane of graphene through 1,3-dipolar cycloaddition method, and then modified by metal nanoparticles. The composites possess outstanding properties of both organic sensitizer and graphene, such as high dye absorption capacity, enhanced electron-transfer ability, optimal acceptor characteristics and transportation property. Under irradiation of light, excited electrons transfer from the sensitizer moiety to graphene through an intramolecular electron transfer and then to the Pt nanoparticles deposited on the graphene nanosheets, resulting in enhanced separation efficiency of photoexcited carriers and low possibility of charge recombination because of the presence of the molecular heterojunction of the composite..By investigation of the photo-harvesting ability, the photoexcited electron transfer and photocatalysis of the sensitizer functionalized graphene composite, the microscopic mechanism and physical intrinsic properties of light-induced electron-transfer between the sensitizer and graphene will be rightly understood. The objectives of this project are trying to find effective methods to manage light-induced electron-transfer on the composite and to provide valuable references for developing the novel photocatalytic material for water splitting to produce hydrogen.

采用1,3-偶极环加成法,在石墨烯二维平面上引入通过化学键联接的卟啉类、酞菁类或联吡啶钌类光敏剂分子，然后与金属纳米粒子复合制得有机光敏剂功能化的石墨烯/金属纳米粒子复合物。这类复合物既具有光敏剂分子优异吸收光能和光电子转移性能也具有石墨烯优异的接受和传递电子性能。光照下，光敏剂分子上的激发电子通过分子内电子转移经石墨烯传输至金属纳米粒子。由于复合物中的分子异质结效应，光生电子回传几率降低，载流子分离效率提高，因而可望成为一类新型光催化材料。.通过研究光敏剂分子功能化石墨烯复合物的光捕获能力、光生电子转移规律以及光催化作用，了解光电子转移的微观机制和物理本质，掌握有效的调控功能化石墨烯纳米复合物光生电子转移方法，为开发光催化分解水反应新材料提供有用的参考依据。

合成了联吡啶钌络合物共价功能化石墨烯、硅酞菁共价功能化石墨烯、硅酞菁共价功能化氮掺杂石墨烯量子点、联吡啶钌敏化TiO2功能化石墨烯、对羟基苯基卟啉非共价功能化石墨烯等系列石墨烯基光催化剂，研究了石墨烯基光催化剂的结构、光激发下电子传递性能和光催化产氢性能。研究了利用表面活性剂提高石墨烯基光催化剂在水相中的分散性能和光催化性能。同时还研究了有机光敏剂/Pt纳米复合物在光激发下分子内的能量传递和有机光敏剂分子与金属Pt纳米粒子间的电子传递性能和光催化产氢性能。. 研究发现有机光敏剂分子功能化石墨烯后，复合物的光捕获范围可拓宽至可见光区，光生电子能够从光敏剂分子上转移至石墨烯，再从石墨烯转移至Pt纳米粒子助催化剂上发生光催化反应。石墨烯作为电子接受体和传递体有效的增强了光生电荷分离效率。有机光敏剂分子共价功能化石墨烯的电子传递效率和光催化效率要远高于相应的非共价功能化石墨烯复合物。. 通过研究光敏剂分子功能化石墨烯复合物的合成、光捕获能力、光生电子转移规律以及光催化作用，初步了解了光电子转移的微观机制和物理本质，为进一步研究石墨烯基光催化分解水制氢反应新材料打下了良好的基础。