双重场效应下氮化碳-铋系复合材料光生电子迁移行为及光催化性能增强机制

光生电荷的高效分离与有效利用是半导体材料改性的研究导向。构建异质结，施加外电场作用是目前提高光生载流子分离效率的主流方法。目前对异质结的研究主要集中在界面处的电子分离，而体相内激发的电子如何迁移至表面以及分离后的载流子如何利用对光催化性能的影响也至关重要。光生电荷的分离本质是正负离子的分离，电场和磁场都能为其分离提供驱动力，从环保和能耗方面考虑，磁场无疑是更优的选择。针对这些问题，本项目拟以C3N4-铋系复合材料为研究对象，通过调控g-C3N4S的磁性研究负磁阻效应，探讨异质结有效接触面积和外磁场作用下对复合材料光催化性能的影响，结合铋系极性半导体的晶面取向和极性强度对异质结界面处电荷有效迁移行为之间的关系，揭示磁场作用下内电场方向和强度对光电荷在界面处和体相内迁移的影响规律，阐明双重场效应下促进光生电子扩散和光催化效应增强的机制，为设计和制备高效的光催化体系提供理论和实验依据。

Electron migration behavior and photocatalytic enhancement mechanism of g-C3N4-bismuth composites under the synergy of double field effect。..The efficient separation and effective utilization of photogenerated charges is the research direction of semiconductor material modification. Constructing a heterojunction and applying an external electric field is currently the mainstream method to improve the efficiency of photogenerated carrier separation...The current research on heterojunction mainly focuses on the separation of electrons at the interface, and how the electrons excited in the bulk phase migrate to the surface and how the separated carriers are used to affect the photocatalytic performance is also crucial...The separation of photogenerated charges is the separation of positive and negative ions. Both electric and magnetic fields can provide a driving force for their separation. From the perspective of environmental protection and energy consumption, magnetic fields are undoubtedly the better choice...In response to these problems, this project intends to take C3N4-bismuth composite materials as the research object, study the negative magnetoresistance effect by adjusting the magnetic properties of g-C3N4S, and explore the effect of heterojunction effective contact area and external magnetic field on the photocatalytic performance of composite influences;..Combining the relationship between the crystal plane orientation and polar strength of the bismuth-based polar semiconductor on the effective transfer behavior of charges at the heterojunction interface, to reveal the law of influence of the direction and intensity of the internal electric field on the migration of photocharges at the interface and in the bulk phase under the action of a magnetic field。..Clarify the mechanism of promoting the diffusion of photogenerated electrons and the enhancement of photocatalytic effect under the double field effect, and provide theoretical and experimental basis for the design and preparation of efficient photocatalytic systems.