纳米隧道结光催化剂的制备及其电荷迁移机制和污染控制性能研究

The photocatalysis is considered as one of the most promising techniques for the control of toxic pollutants. However, the low energy efficiencies of the technology in pollution control is currently one of the major problems that restrict its practical application. Heterojunction photocatalysts can improve the photogenerated charge separation and sequentially enhance the energy efficiency, however its oxidation and reduction capabilities are weakened，and this disadvantage limited the development of heterojunction photocatalyst in toxic pollutant control. In the project, tunnel junction with the unique photogenerated charge transfer approach will be introduced in area of pollution control. It can provide photogenerated electrons with high reduction capability and holes with high oxidation capability.Therefore,it is reasonable to expect that the tunnul junction can carry out good performance in both pollutant degradation and light energy conversion.The results are significant for the design and synthesis of tunnel junction as photocatalysts, detection of their photogenerated change transfer and control method, and their application in the pollution control.

光催化被认为是降解毒性污染物最具发展前景的新技术之一，如何提高能量效率是其面临的主要科学问题。异质结材料虽然能够有效促进光生电荷分离，提高能量效率，但是其代价是氧化还原能力降低，限制了其在毒性污染物降解领域的应用。本研究提出构建隧道结光催化材料，利用其特殊的光生电荷电荷迁移方式，在确保有效促进光生电荷分离的前提下能够利用高氧化还原能力的光生电荷降解污染物，实现光催化技术对有毒污染物的高效治理。拟开展的研究工作对开发隧道结材料的制备技术，深入了解其光生电荷迁移和调控机制，并探索其在光催化领域的应用途径具有指导意义。

光催化被认为是降解毒性污染物最具发展前景的新技术之一，如何提高能量效率是其面临的主要科学问题。拓展光吸收范围、促进光生电荷分离是提高能量效率的有效途径。本项目构建基于硅纳米材料的异质结，结合Si的宽吸收范围和异质结内建电场的光生电荷迁移能力，实现拓展光吸收范围同时促进光生电荷分离。制备出Ag/SiNW/SiNP、C3N4纳米片/SiNW、C3N4量子点/SiNW、SnO2/Si、Si量子点/SiNW、Si纳米孔/SiNW等6种硅基异质结和TiOx/Si、WO3-Cu-gC3N4等两种隧道迁移异质结。由于光吸收范围拓展和电荷分离效率提高，这些异质结材料的光生电流密度比单一光催化材料提高1.3~5倍。阐明了内建电场提高光生电荷分离效率的机制。相对于传统催化剂，上述异质结光催化去除苯酚、4-氯酚、壬基酚、Cr6+等典型污染物的动力学常数提高2.2~7倍。利用CFD软件设计了传质、采光能力优于常用的折板或平板组件的单螺旋、双螺旋光催化组件，制造出3套连续流动式光催化消毒器，处理能力分别为1.8 m3/d、3.6 m3/d、24m3/d。对E.coli、噬菌体MS2和f2的处理效率优于紫外消毒技术，且能够抑制紫外消毒过程的微生物复活现象。对磺胺甲恶唑、双酚A等微量有机污染物也有一定去除效果。研究成果对开发异质结光催化材料的制备技术，深入了解其光生电荷迁移和调控机制，促进光催化技术的应用具有参考价值。