磁性硼掺杂氧化银宽光谱高效光催化剂机理研究和可控制备

We found that the borate-doped silver oxide semiconductor could photo-degrade organic pollutant with high degraded speed under solar light. But its working mechanism under light irradiation and the function of doped borate in this process is not clear yet, and its performance, stability and light utilization efficiency can be improved further. And for further application, the cost of Ag2O photocatalyst should be lowered and the recovery rate should be increased, and the specialized reactor for such Ag2O photocatalyst with high photo-reaction rate should be studied and designed. The construction of core-shell structure by loading B-doped Ag2O on the surface of magnetic nano-particles, and application of such core-shell magnetic photo-catalyst in magnetically stabilized bed photo- reactor is a feasible approach for utilization and recovery of such high-performance photocatalyst. In this strategy, the understanding of the working mechanism of Ag2O photocatalyst, the function of doped borate in Ag2O photocatalytic process, the loading of Ag2O on magnetic particles, and the building of magnetically stabilized suspended photoreactor are the key problems to be resolved. The systematic research of photocatalytic route of photocatalyst with narrow band gap and the role of borate in photocatalytic process can help to further improve the performance, stability and light utilization efficiency of photocatalyst. The study of the influence of magnetic nano-particles on the performance of photocatalyst, the mass transfer and reaction kinetics of high-performance photocatalyst under light irradiation, and the model of mass-transfer and reaction in magnetically stabilized suspended photoreactor can provide the theoretical basis for application of high-performance photocatalyst.

我们发现，氧化银经硼掺杂后可在太阳光下实现有机物快速降解，但其快速降解机理及硼在该过程中作用还待研究，面向应用适合于快速光催化剂的光反应器还待开发。研究硼掺杂氧化银半导体光催化过程机理并考察硼掺杂的作用，将经硼掺杂调控性能和稳定性的氧化银光催化剂负载于磁性纳米颗粒上，构建磁性核壳型硼掺杂氧化银高效光催化剂用于构建磁稳定床光催化反应器是解决上述问题的可行方法。氧化银光催化剂反应机理和降解途径的研究、硼对氧化银光催化剂性能和寿命影响的考察、磁性纳米颗粒上氧化银的负载、光催化磁悬浮反应床的构建是关键。研究氧化银的光催化途径和硼在氧化银光催化过程中的作用机理可为进一步提高窄禁带光催化剂性能、稳定性和光利用效率提供参考；考察磁性纳米颗粒对光催化剂性能影响，明确快速光催化剂光照条件下传质和反应动力学规律，构建其在磁稳定床系统中的传质反应模型，可为快速光催化剂规模应用提供理论基础。

开发快速高效光催化剂并构建适用于快速光催化剂的光反应器是光催化技术实用化需求。本项目尝试通过硼掺杂提升氧化银光催化剂性能，并将其负载于磁性颗粒上得到磁性核壳结构氧化银高效光催化剂，以之为基础构建磁稳定床光催化反应器，实现对有机污染物的快速高效光催化氧化降解。研究工作按照计划进行并基于研究结果进行了有效拓展。通过硼掺杂，氧化银光催化剂性能显著提升，实现了可见光下120s内快速降解甲基橙和10min内完全矿化苯酚；硼酸在氧化银的制备过程中起到了晶核稳定剂、晶化助剂和提高量子效率的作用，有效增强了氧化银的光催化活性和稳定性。制备了具超浸润特性的氧化银光催化剂实现对含油废水的处理；制备了具强吸附性的氧化银光催化剂实现了光催化辅助强化吸附过程；明确了氧化银光催化过程中偶氮染料具协同氧化效应，可强化非偶氮有机物的快速降解。氧族银化合物均具有可见光和近红外 光催化性能，其中氧化银和硫化银性能优越，具发展前景；采用Fe3O4磁性颗粒和多种铁氧体均可实现磁性负载型氧化银光催化剂的构建，在最优负载比例下，磁性载体的引入不会引起氧化银光催化剂性能降低，与未负载氧化银光催化性能和稳定性一致；催化剂磁性良好，可实现快速磁性分离，首次磁回收率可达98.7%。以所得磁性负载型氧化银光催化剂构建磁稳定光催化反应器，太阳光下多次重复实验中，甲基橙溶液在60分钟内光催化剂降解效率可达80%，残留量符合废水排放标准；在磁稳定光催化反应器中，由于光催化剂性能提升，传质过程是降解过程速率控制步骤，需进一步改进该反应器实现传质强化。此外，本研究还开发了基于铋酸钾的异质结光催化剂和磁性光催化剂，可见光下性能优良稳定，具开发前景。研究所获的氧化银光催化剂和铋酸钾光催化剂性能优良，磁稳定光反应器稳定可用，均具应用前景，为推动光催化技术实用化提供了参考。目前本项目形成了2份专利，发表了有标注文章24篇，待发表文章5篇。