Asymmetric Fe-Ov-Co Synergizing Free Nitrogen Sites in Carbon-Support Spinel Nanodots - Dual-Engineered Electronic States for High-Efficiency Peroxymonosulfate Activation
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-08-05 |
| Journal | ACS Applied Materials & Interfaces |
| Authors | Minyi Liang, Wenxin Yang, Chenghao Ye, C.Y. Wang, Jiaxin Huang |
| Institutions | Key Laboratory of Guangdong Province, Shantou University |
Abstract
Section titled âAbstractâOxygen vacancies (O<sub>v</sub>) play an important role in promoting peroxymonosulfate (PMS) activation. However, conventional symmetric O<sub>v</sub> exhibits low electron transfer efficiency due to symmetric adjacent cations, constraining their catalytic performance. Asymmetric vacancies (M<sub>1</sub>-O<sub>v</sub>-M<sub>2</sub>) offer enhanced catalytic potential, yet developing catalysts featuring uniformly distributed asymmetric O<sub>v</sub> remains challenging. Incorporating supports with N-bonded functionalities can modulate the electronic structure of metal oxides, providing a promising strategy to overcome these limitations. Here, we designed a 3D porous N-bonded carbon-supported CoFe<sub>2</sub>O<sub>4-<i>x</i></sub> spinel nanodots catalyst featuring rich and structurally uniform asymmetric Fe-O<sub>v</sub>-Co sites and free nitrogen sites for PMS activation in <i>p</i>-nitrophenol degradation. Through carrier engineering and the integration of functional nonmetallic sites, this catalyst achieves a high degradation rate constant (0.12 min<sup>-1</sup>) and exceptional cycling stability. The synergistic catalytic mechanism between asymmetric vacancies and free N species in PMS activation was elucidated. Specifically, asymmetric O<sub>v</sub> in the spinel, combined with N-bonded functionalities in the support, optimizes the electronic states near the Fermi level, promoting faster electron transfer and enhancing reactive oxygen species (ROS) generation. The synergy between asymmetric O<sub>v</sub> and pyrrolic N sites improves PMS adsorption and activation, while the combination of O<sub>v</sub> and pyridinic N lowers the catalystâs d-band center by 0.29 eV, facilitating ROS release. Additionally, O<sub>v</sub> and pyrrolic N cooperatively enhance <i>p</i>-nitrophenol adsorption, enabling in situ degradation by surface ROS and accelerating degradation kinetics. This work not only advances defect engineering in catalysts but also unveils the âoxygen vacancy-nitrogen synergyâ mechanism, providing valuable insights for designing multiactive-site catalysts in complex environmental systems.