自组装卟啉/g-C3N4二维复合结构的界面电荷分离及产氢活性增强机制

The research on the catalyst with full spectrum response of visible light and strong photo-induced charge separation is of great significance for greatly improving the photocatalytic hydrogen production. This project intends to layer-by-layer combine porphyrin conjugated π material which has high molar absorption coefficient with g-C3N4 which has high apparent quantum efficiency to obtain a 2D/2D composite structure with full-spectrum response of visible light, strong interfacial electric field and high hydrogen production activity. And this project aims to illuminate the mechanism on the enhancement of charge separation and hydrogen production via this 2D/2D self-assembled porphyrin/g-C3N4. Through electrostatic self-assembly technology, the regulation on π-π interaction between porphyrins/g-C3N4 interface and the adjustment on layer number and layer thickness of this 2D/2D composite structure will be realized. By adjusting the layer number and layer thickness and the controllable preparation of this structure, the light absorption of this porphyrin/g-C3N4 composite can be extended to 700 nm. Through the regulation on π-π interaction the polarized built-in electric field between porphyrins/g-C3N4 interface will be enhanced, thereby accelerating the the photo-induced charge separation. Through adjusting the thickness and number of each component layers in this composite, the charge transfer channel number and charge transfer distance can be regulated, thereby promoting the charge separation and transfer on porphyrin/g-C3N4 interface. Thus higher hydrogen production activity over this self-assembled porphyrin/g-C3N4 with 2D/2D composite structure will be obtained. This project will be helpful to clarify the mechanism on the enhancement of interfacial charge separation and hydrogen production via this self-assembled porphyrin/g-C3N4 with 2D/2D composite structure, and will promote the development of photocatalys with full spectrum response of visible light.

催化剂的可见光全谱响应和光生电荷分离增强，对于大幅提高光解水产氢性能具有重要意义。本课题拟通过将具有高摩尔吸光系数的卟啉共轭π材料与具有高表观量子效率的g-C3N4进行层层自组装，来获得具有可见光全谱响应、高界面电荷分离效率和高产氢活性的自组装卟啉/g-C3N4复合结构催化剂，并阐明其界面电荷分离及产氢活性增强机制。采用静电自组装技术，调节层间界面π-π作用，实现该复合材料层数和层厚的调控以及自组装结构的可控制备，拓展其光吸收至700纳米。通过调节界面间π-π作用，增强卟啉/g-C3N4界面的内建电场，促进光生电荷分离。通过调节自组装卟啉/g-C3N4复合结构的层数和层厚，实现对电荷传输通道数目和电荷传输距离的调控，促进光生电荷迁移，获得高产氢活性。本课题的实施有助于阐明自组装卟啉/g-C3N4二维复合结构的界面电荷分离机制及产氢活性增强规律，对可见光全谱响应光催化剂的发展具有促进作用。

本研究利用光能进行制氢、CO2还原、降解有机污染物和抗生素，对于减少化石燃料的过度燃烧、缓解大气污染和水体污染等问题具有重要意义。所制备的9种新型光催化剂有利于兼顾环境友好、人类健康和经济发展的可持续发展目标。分别采用水热法、机械混合法、高能球磨法、原位掺杂结合冷冻干燥法得到了Sn3O4/聚吡咯、聚苯胺/Sn3O4、SnO2-x/Sb2O3、Bi缺陷BiOCl、N缺陷g-C3N4、ZnFe2O4/MoS2、In2O3/ZnIn2S4、α-Fe2O3/g-C3N4、InVO4/Ti3C2Tx等光催化剂。Sn3O4/聚吡咯实现了光生电子的定向诱导迁移且在5 h内实现了481.05 μmol·g-1可见光产氢；聚苯胺/Sn3O4保证了界面处足够的载流子分离从而5 h内光催化降解有机染料RhB效率达到了96.84%；缺陷工程和异质结的协同作用使SnO2-x/Sb2O3获得了宽光吸收和高光生电荷分离率，提高了IPA光降解性能，采用机械球磨法有助于实现光催化剂的工业化生产；富含铋空位的暴露高活性(001)晶面的玫瑰状BiOCl在空气中经过5 h光照生成了21.99μmol· g-1·h-1的CO，突破了传统光催化体系需要压缩/纯化CO2的局限，为实际应用大幅降低了成本；多孔结构和氮缺陷协同增加了CO2吸附和活性位点，光还原CO2产CO、CH4量分别为19.7umol·g -1、37.1umol·g-1，为构建其他高性能的无金属光催化还原CO2体系提供了新思路；MoS2/ZnFe2O4实现了95 %的盐酸四环素降解率，MoS2与ZnFe2O4异质结有效提高了光催化性能且可以在外加磁场下快速回收；多级中空结构In2O3/ZnIn2S4多孔微管之间电荷的多级跳跃减少了光生载流子复合，积累了CO2局部浓度，促进了CO2吸收及反应物/产物的快速扩散，为开发用于人工光合作用的中空光催化剂提供了新思路；人工树枝状αFe2O3/gC3N4具有高电子传导的(001)晶面有利于光生电子分离，且Z-scheme结构有助于促进CO2吸附和抑制载流子复合，为构建用于CO2转化的Z型光催化剂提供了新见解；3D绣球花状InVO4/Ti3C2Tx独特的2D/2D界面作用有效提高了光生电荷的定向分离，得到了13.83 μ mol·g-1·h -1CO和92%选择性，为开发理想光催化剂提供了新途径。