Chen Hui, Zeng Wengao, Liu Yutang, Dong Wanyue, Cai Tao, Tang Lin, Li Juan, Li Wenlu
College of Environmental Science and Engineering, Hunan University, Lushan South Road, Yuelu District, Changsha 410082, People's Republic of China.
Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Lushan South Road, Yuelu District, Changsha 410082, People's Republic of China.
ACS Appl Mater Interfaces. 2021 Apr 14;13(14):16364-16373. doi: 10.1021/acsami.1c01308. Epub 2021 Apr 1.
It is important to find an effective way to enhance the photocatalytic efficiency of metal-organic frameworks. In this work, an organic supermolecule perylene diimide (PDI) semiconductor with a carboxyl terminal was added into the synthesis process of MIL-53(Fe) crystals. The PDI/MIL-53(Fe) (PM) composite photocatalyst was first obtained. The TC-H photodegradation rate of the most efficient 5PM was nearly 94.08% within 30 min, whose apparent reaction rate constant () is 4 times that of PDI and 33 times that of MIL-53(Fe), respectively. By investigation and characterization, it has been found that PDI nanofibers were dispersed and fixed in MIL-53(Fe) and bonded to each other by covalent bonds. The radical trap experiments and electron spin resonance analysis illustrated that hydroxyl radical (·OH), superoxide radical (·O), and photogenerated holes (h) were active species. Combined with the band structure of PDI and MIL-53(Fe), it is proposed that the PM photocatalyst was a Z-scheme heterojunction mechanism. Therefore, PM photocatalysts showed excellent charge separation and transfer ability. The performance improvement of 5PM is due to enhanced visible light absorption, efficient charge separation, and excellent redox potential. Five cyclic photocatalytic tests and experiments further demonstrate that the 5PM photocatalyst has a promising future for pollutant removal.
找到一种提高金属有机框架光催化效率的有效方法很重要。在这项工作中，将一种带有羧基末端的有机超分子苝二酰亚胺（PDI）半导体添加到MIL-53（Fe）晶体的合成过程中。首次获得了PDI/MIL-53（Fe）（PM）复合光催化剂。最有效的5PM在30分钟内对TC-H的光降解率接近94.08%，其表观反应速率常数（）分别是PDI的4倍和MIL-53（Fe）的33倍。通过研究和表征发现，PDI纳米纤维分散并固定在MIL-53（Fe）中，并通过共价键相互结合。自由基捕获实验和电子自旋共振分析表明，羟基自由基（·OH）、超氧自由基（·O）和光生空穴（h）是活性物种。结合PDI和MIL-53（Fe）的能带结构，提出PM光催化剂为Z型异质结机理。因此，PM光催化剂表现出优异的电荷分离和转移能力。5PM的性能提升归因于可见光吸收增强、电荷有效分离和出色的氧化还原电位。五次循环光催化测试和实验进一步证明，5PM光催化剂在污染物去除方面具有广阔的前景。
