稀土离子掺杂诱导α/β-Bi5O7I异相结光催化材料的构建及其光生电荷传输行为的研究

Elimination of pollutants using semiconductor photocatalytic technology to solve the environment pollution is a hot research topic in recent years. In this project, the rare earth ions doped α/β-Bi5O7I phase-heterojunction photocatalytsts will be constructed by in situ thermal decomposition of porous sphere-like rare earth ion doped BiOI prepared by a solvothermal process. The ratio of α/β phases in the α/β-Bi5O7I phase-heterojunction will be adjusted by controlling the doping concentration or species of doped rare earth ions. This new kind of α/β-Bi5O7I phase-heterojunctions will be used as photocatalysts for NOx elimination in air. Based on experimental and theoretical investigations, the behavior of photogenerated charge transport in the heterojunction will be researched. Furthermore, the relationship between the photocatalytic activity and its microstructure will be studied. Finally, the photocatalytic enhanced mechanism of α/β-Bi5O7I phase-heterojunctions will be obtained. Moreover, the upconversion Er3+/Yb3+ and Tm3+/Yb3+ codoped α/β-Bi5O7I phase-heterojunction composite structures will also be prepared, which will improve the utilization of visible and infrared light in solar light. The mechanism of upconversion enhanced photocatalytic activity will be revealed. The achievements of the project will provide experimental and theoretical basis for development and application of new phase-heterojunction photocatalyst materials with broad-spectrum response and high photocatalytic efficiency.

利用半导体光催化技术去除污染物来解决环境污染问题是近年来的研究热点。本项目拟采用溶剂热法制备稀土离子掺杂BiOI多孔球形结构，再通过原位热分解法构筑稀土离子掺杂的α/β-Bi5O7I异相结光催化材料，通过改变稀土离子或掺杂浓度来调控异相结中两相的比例，并以此新型复合结构为光催化剂催化去除空气中NOx，结合实验与理论计算，研究异相复合体系中光生载流子的传输行为，探究光催化活性与其微观结构的构效关系，获得稀土离子掺杂α/β-Bi5O7I纳米异相复合结构的光催化增强机制；构建具有上转换效应的（Er3+/Yb3+和Tm3+/Yb3+）稀土离子双掺杂α/β-Bi5O7I纳米异相结复合结构，进一步提高太阳能光谱中可见和红外光的利用率，揭示其上转换增强光催化反应机理，以期获得高效率宽谱响应的α/β-Bi5O7I异相复合光催化材料，为异相结光催化材料的研发和应用提供实验和理论支持。

利用半导体光催化技术去除污染物来解决环境污染问题是近年来的研究热点。本项目通过将大离子半径稀土离子Re3+( La，Ce，Pr, Nd)掺杂到α-Bi5O7I中，获得大量的氧缺陷，在保持相结构不变的基础上改变α-Bi5O7I的能带结构，从而提升其对可加光的利用率来增强光催化剂的催化活性；而将小离子半径稀土离子Re3+( Er, Tm, Yb, Lu) 掺入α-Bi5O7I后，会发生相转变而形成Re3+/α/β-Bi5O7I异相结复合结构，即较小的半径的Re3+使得Bi5O7I的晶胞发生了畸变，使得晶体结构由正交相(α-)向单斜相(β-)进行转变，从而形成了Re3+/α/β-Bi5O7I异相结复合结构，从而有利于光生载流子在异相结复合结构中分离，大幅度提升稀土离子掺杂 α/β-Bi5O7I 复合光催化剂的光催化性能，获得稀土离子掺杂 α/β-Bi5O7I 纳米异相复合结构对其光催化性能的影响规律，揭示了稀土离子掺杂异相结复合结构协同增强作用机理；构建具有上转换效应的（Er3+/Yb3+和Tm3+/Yb3+）稀土离子双掺杂α/β-Bi5O7I纳米异相结复合结构，进一步提高太阳能光谱中可见和红外光的利用率，揭示其上转换增强光催化反应机理，获得了高效率宽谱响应的α/β-Bi5O7I异相复合光催化材料，通过第一性原理模拟计算，分析了光生载流子在异相结复合结构中的传输行为，为异相结光催化材料的研发和应用提供实验和理论支持。