基于g-C3N4构建的全有机Z型光催化体系结构优化及其光催化去除氮氧化物性能研究

As a common gaseous pollutant, nitric oxide (95% is NO) causes environmental problems, such as acid rain and ozone depletion. Previous work demonstrated that an organic Z-scheme photocatalyst (PI-g-C3N4) consisting of g-C3N4 surface modified with perylene imides (PTCDI) could effectively oxidize NO to NO3-. However, the molecular structure of this organic Z-scheme photocatalyst has not been optimized, thus leading to the instability of PTCDI and the low-effective interface transfer of photogenerated electrons. Our previous experiments found that these two problems were caused by the higher LUMO energy level of PTCDI. This is because the higher LUMO energy level may produce the strong reducing electrons, which can reduce oxygen gas. We all know that the energy level structure of organic semiconductors is closely related to their molecular structure. This project will modify the electron-donating group or electron-withdrawing group in the Meta position of PTCDI molecule to reduce the LUMO energy level of the PTCDI molecule, so as to reduce the reduction ability of the LUMO orbital electron of the PTCDI molecule. Then, the oxygen activation on the surface of PTCDI molecules can be inhibited. Finally, the stability, interface electron transport, and the NO removal activity of the organic Z-scheme photocatalyst can be further improved. Based on this research, we will get the basic laws and underlying causes of the fact that the stability, the interface electron transport, and the NO removal activity of the organic Z-scheme photocatalyst can be well turned by adjusting the meta-substituent of PTCDI molecle. This project not only can help us master the relationship between microstructure and performance of organic Z-scheme photocatalyst, but also can provide the theoretical basis for the development of new NO removal photocatalysts.

空气中低浓度氮氧化物(95%为NO)是一种重要的空气污染物。研究表明以g-C3N4和PTCDI分子构建的全有机Z型光催化体系可以有效的将NO通过光催化作用氧化为硝酸根。然而，该体系使用过程中存在结构稳定性差和界面电子传输效率低的问题。原因是该体系中PTCDI分子LUMO轨道能级比较高，PTCDI分子表面光生电子容易还原O2。基于有机分子的能级结构取决于分子结构的原理，本项目拟在该体系PTCDI分子湾位修饰取代基来优化其能级结构，抑制光催化过程中O2从PTCDI分子表面得电子，达到提高全有机Z型光催化体系光催化去除NO过程中的结构稳定性、界面电子传输效率、以及去除NO活性的目的。揭示PTCDI分子湾位取代基对全有机Z型光催化体系结构稳定性、界面的电子传输效率、以及去除NO活性影响的规律和内在机理。掌握全有机Z型光催化体系微观结构与性能之间的构效关系，为开发新型NO去除光催化剂提供理论依据。

空气中低浓度氮氧化物(95%为NO)是一种重要的空气污染物。研究表明以g-C3N4和PTCDI分子构建的全有机Z型光催化体系可以有效的将NO通过光催化作用氧化为硝酸根。然而，该体系使用过程中存在结构稳定性差和界面电子传输效率低的问题。原因是该体系中PTCDI分子LUMO轨道能级比较高，PTCDI分子表面光生电子容易还原O2。基于有机分子的能级结构取决于分子结构的原理，本项目在该体系PTCDI分子湾位修饰取代基来优化其能级结构，抑制光催化过程中O2从PTCDI分子表面得电子，达到提高全有机Z型光催化体系光催化去除NO过程中的结构稳定性、界面电子传输效率、以及去除NO活性的目的。揭示了PTCDI分子湾位取代基对全有机Z型光催化体系结构稳定性、界面的电子传输效率、以及去除NO活性影响的规律和内在机理。掌握了全有机Z型光催化体系微观结构与性能之间的构效关系，为开发新型NO去除光催化剂提供了理论依据。