Kim, Minsung Lee, Hyein Kim, Junseo Yu, Hongju Yu, Taekyung Jeong, Keunhong Kim, Jongsik 2024-11-30T07:30:14Z 2024-11-30T07:30:14Z 2024-11-30 2024-12 0925-8388 https://pubs.kist.re.kr/handle/201004/151243 Fes+/3+ defects on FeOCl surface interact with H2O2 to produce diverse reactive oxygen species (ROS) including center dot OH, center dot OOH, O2 center dot-, Fe4+=O, and 1O2, whose relative contributions to aqueous pollutant degradation have been debatable and only partially clarified. Herein, SiO2 with O2- acting as an electron donor served to encapsulate FeOCl to form FeOCl-SiO2, whose interface bore Fes+/3+ distinct from those of FeOCl surface under H2O2-containing aqueous phases in terms of composition and electron affinity. The FeOCl-SiO2 interface bore plentiful Fes+ and minute Fe3+, from which Fe4+=O was generated yet remained barely accessible to bulky contaminants. Conversely, the FeOCl surface afforded plentiful Fe3+ and a non-negligible amount of Fes+, from which copious O2 center dot- and a moderate amount of Fe4+=O were produced, respectively, with high accessibility to bulky pollutants. Albeit with the production of center dot OH on FeOCl and FeOCl-SiO2, plots of their initial contaminant decomposition rates versus contaminant ionization potentials subjected to the correction for contaminant adsorption or Fes+/3+ leaching along with scavenging/recycle runs corroborated that Fe4+=O and/or 1O2 function as the major ROS in fragmenting aqueous wastes upon exposure of the FeOCl-containing catalysts to H2O2-rich conditions. This was unanticipated when considering that the lifetimes and redox potentials of Fe4+=O and 1O2 are smaller than the corresponding values of center dot OH and that the evolution of center dot OH, Fe4+=O, and 1O2 on FeOCl was energetically favorable, as demonstrated by density functional theory calculations. English Elsevier BV Reinventing primary reactive oxygen species evolved from H2O2 heterolysis on FeOCl via SiO2 encapsulation Article 10.1016/j.jallcom.2024.176782 1 Journal of Alloys and Compounds, v.1008 Journal of Alloys and Compounds 1008 N scie scopus 001347543500001 2-s2.0-85205534176 Chemistry, Physical Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Chemistry Materials Science Metallurgy & Metallurgical Engineering Article HYDROXYL RADICALS DEGRADATION GENERATION CATALYST ZRO2 Iron oxychloride Hydroxyl radical Hydroperoxyl radical Superoxyl radical Highly valent oxo-iron Singlet oxygen