低温光催化脱氟 z-bio 2025-01-03 471

　　With the support of the National Natural Science Foundation of China project (Approval No. 22271268) and other grants, the team led by Kang Yanbiao from the University of Science and Technology of China, in collaboration with Qu Jianping from Nanjing University of Technology, has made progress in the low-temperature defluorination and degradation of perfluorinated and polyfluoroalkyl substances (PFASs). The related achievements were published online in the journal Nature on November 20, 2024, under the title "Photocatalytic low-temperature photocatalytic defluorination of PFASs". Paper link: https://www.nature.com/articles/s41586-024-08179-1 .

　　PFASs have a large number of strong carbon fluorine bonds within their molecules, resulting in unique thermal stability, chemical stability, and hydrophobic and oleophobic properties. They are widely used in fields such as chemical engineering, electronics, medical equipment, textile machinery, and nuclear industry. However, the inertness of carbon fluorine bonds makes PFASs difficult to degrade in natural environments or under mild conditions, and PFASs are therefore referred to as "permanent chemicals". For example, polytetrafluoroethylene can maintain stability for several years at 260 ℃, and its pyrolysis usually occurs above 500 ℃, releasing toxic gases. The massive accumulation of discarded PFASs in nature has caused a series of environmental and health risks. At present, achieving defluorination of polytetrafluoroethylene at low temperatures (<100 ℃) often requires the use of super strong reducing agents based on active species such as alkali metals. Therefore, there is an urgent need to explore new methods for the defluorination and degradation of PFASs that are mild, efficient, and easy to implement.

　　In response to these challenges, the above-mentioned research team utilized the strategy of surface distortion to promote electron gain and loss, designed and synthesized a series of molecules containing highly distorted carbazole core structures, and utilized their super reducibility under specific light to achieve complete defluorination and mineralization of polytetrafluoroethylene at lower temperatures (40-60 ℃) for the first time, efficiently converting it into inorganic fluoride salts and carbon resources. Experiments have shown that the unique twisted structure of this type of catalyst can effectively promote electron transfer. In addition, the photocatalytic reduction catalyst has a broad-spectrum ability to catalyze the cleavage of carbon fluorine and carbon carbon bonds, and is suitable for the defluorination degradation of various perfluoroalkyl small molecules and their derivatives.