Liang Danli, Liu Jiarong, Wang Chunlin, Tu Kaipeng, Wang Li, Qiu Lili, Zhang Xiuhui, Liu Ling
Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Key Laboratory of National Land Space Planning and Disaster Emergency Management of Inner Mongolia, School of Resources, Environment and Architectural Engineering, Chifeng University, Chifeng 024000, China.
Toxics. 2024 Aug 10;12(8):582. doi: 10.3390/toxics12080582.
The formation of environmentally persistent free radicals (EPFRs) is mediated by the particulate matter's surface, especially transition metal oxide surfaces. In the context of current atmospheric complex pollution, various atmospheric components, such as key atmospheric oxidants ·OH and O, are often absorbed on particulate matter surfaces, forming particulate matter surfaces containing ·OH and O. This, in turn, influences EPFRs formation. Here, density functional theory (DFT) calculations were used to explore the formation mechanism of EPFRs by CHOH on α-FeO(0001) surface containing the ·OH and O, and compare it with that on clean surface. The results show that, compared to EPFRs formation with an energy barrier on a clean surface, EPFRs can be rapidly formed through a barrierless process on these surfaces. Moreover, during the hydrogen abstraction mechanism leading to EPFRs formation, the hydrogen acceptor shifts from a surface O atom on a clean surface to an O atom of ·OH or O₃ on these surfaces. However, the detailed hydrogen abstraction process differs on surfaces containing oxidants: on surfaces containing ·OH, it occurs directly through a one-step mechanism, while, on surfaces containing O, it occurs through a two-step mechanism. But, in both types of surfaces, the essence of this promotional effect mainly lies in increasing the electron transfer amounts during the reaction process. This research provides new insights into EPFRs formation on particle surfaces within the context of atmospheric composite pollution.
环境持久性自由基（EPFRs）的形成由颗粒物表面介导，尤其是过渡金属氧化物表面。在当前大气复合污染背景下，各种大气成分，如关键大气氧化剂·OH和O，常吸附在颗粒物表面，形成含·OH和O的颗粒物表面。这进而影响EPFRs的形成。在此，采用密度泛函理论（DFT）计算来探究CHOH在含·OH和O的α-FeO(0001)表面上形成EPFRs的机理，并将其与在清洁表面上的形成机理进行比较。结果表明，与在清洁表面上形成EPFRs存在能垒相比，在这些表面上EPFRs可通过无垒过程快速形成。此外，在导致EPFRs形成的氢提取机理中，氢受体从清洁表面上的表面O原子转移到这些表面上·OH或O₃的O原子上。然而，在含氧化剂的表面上详细的氢提取过程有所不同：在含·OH的表面上，它通过一步机理直接发生，而在含O的表面上，它通过两步机理发生。但是，在这两种类型的表面上，这种促进作用的本质主要在于增加反应过程中的电子转移量。本研究为大气复合污染背景下颗粒物表面EPFRs的形成提供了新的见解。
