First-principles study on the heterogeneous formation of environmentally persistent free radicals (EPFRs) over α-Fe2O3(0001) surface: Effect of oxygen vacancy.
First-principles study on the heterogeneous formation of environmentally persistent free radicals (EPFRs) over α-Fe2O3(0001) surface: Effect of oxygen vacancy.
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DOI：
10.1016/j.jes.2023.07.021
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发表时间：
2023-07
影响因子：
6.9
通讯作者：
Wenxiao Pan;ShuMing He;Q. Xue;Xian Liu;Jianjie Fu;K. Xiao;A. Zhang
中科院分区：
文献类型：
--
作者：
Wenxiao Pan;ShuMing He;Q. Xue;Xian Liu;Jianjie Fu;K. Xiao;A. Zhang
含氧空位的金属氧化物对垃圾焚烧过程中有机污染物转化的催化活性有重要影响。基于第一性原理计算，研究了赤铁矿表面氧点缺陷对酚类化合物生成环境持久性自由基（EPFRs）的影响.两个缺氧的条件被认为是：在上表面和次表面上的氧空位。模拟结果表明，氧空位的存在增强了苯酚在α-Fe 2 O3（0001）表面的吸附强度.然而，氧空位的存在对苯酚分子的解离具有负面影响，特别是对于在顶层具有缺陷点的表面。在300-1000 K的温度范围内建立了热动力学参数，并观察到较低的反应速率常数的酚O-H键的断裂在缺氧的表面相比，原始表面。缺氧条件引起的负面影响可归因于FeIII到FeII的局部还原，这降低了表面反应位点的氧化能力。本研究的结果为我们提供了一个很有前途的方法来调节EPFRs的形成。
Metal oxides with oxygen vacancies have a significant impact on catalytic activity for the transformation of organic pollutants in waste-to-energy (WtE) incineration processes. This study aims to investigate the influence of hematite surface oxygen point defects on the formation of environmentally persistent free radicals (EPFRs) from phenolic compounds based on the first-principles calculations. Two oxygen-deficient conditions were considered: oxygen vacancies at the top surface and on the subsurface. Our simulations indicate that the adsorption strength of phenol on the α-Fe2O3(0001) surface is enhanced by the presence of oxygen vacancies. However, the presence of oxygen vacancies has a negative impact on the dissociation of the phenol molecule, particularly for the surface with a defective point at the top layer. Thermo-kinetic parameters were established over a temperature range of 300–1000 K, and lower reaction rate constants were observed for the scission of phenolic O-H bonds over the oxygen-deficient surfaces compared to the pristine surface. The negative effects caused by the oxygen-deficient conditions could be attributed to the local reduction of FeIIIto FeII, which lower the oxidizing ability of surface reaction sites. The findings of this study provide us a promising approach to regulate the formation of EPFRs.