Liang Minyi, Yang Wenxin, Ye Chenghao, Wang Churong, Huang Jiaxin, Zhou Ce, Jiang Wenhao, Cui Beibei, Zeng Yanxin, Xia Haidong, Lu Fushen, Xia Hong
Guangdong Engineering Technology Research Center of Advanced Polymer Synthesis, Key (Guangdong-Hong Kong Joint) Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, College of Chemistry and Chemical Engineering, Shantou University, Shantou, Guangdong 515063, China.
ACS Appl Mater Interfaces. 2025 Aug 20;17(33):46924-46935. doi: 10.1021/acsami.5c06919. Epub 2025 Aug 5.
Oxygen vacancies (O) play an important role in promoting peroxymonosulfate (PMS) activation. However, conventional symmetric O exhibits low electron transfer efficiency due to symmetric adjacent cations, constraining their catalytic performance. Asymmetric vacancies (M-O-M) offer enhanced catalytic potential, yet developing catalysts featuring uniformly distributed asymmetric O 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 CoFeO spinel nanodots catalyst featuring rich and structurally uniform asymmetric Fe-O-Co sites and free nitrogen sites for PMS activation in -nitrophenol degradation. Through carrier engineering and the integration of functional nonmetallic sites, this catalyst achieves a high degradation rate constant (0.12 min) and exceptional cycling stability. The synergistic catalytic mechanism between asymmetric vacancies and free N species in PMS activation was elucidated. Specifically, asymmetric O 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 and pyrrolic N sites improves PMS adsorption and activation, while the combination of O and pyridinic N lowers the catalyst's d-band center by 0.29 eV, facilitating ROS release. Additionally, O and pyrrolic N cooperatively enhance -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 "oxygen vacancy-nitrogen synergy" mechanism, providing valuable insights for designing multiactive-site catalysts in complex environmental systems.
氧空位（O）在促进过一硫酸盐（PMS）活化方面起着重要作用。然而，传统的对称氧空位由于相邻阳离子对称，电子转移效率较低，限制了它们的催化性能。不对称空位（M-O-M）具有更高的催化潜力，但开发具有均匀分布的不对称氧空位的催化剂仍然具有挑战性。引入具有N键功能的载体可以调节金属氧化物的电子结构，为克服这些限制提供了一种有前景的策略。在此，我们设计了一种三维多孔N键合碳负载的CoFeO尖晶石纳米点催化剂，其具有丰富且结构均匀的不对称Fe-O-Co位点以及用于PMS活化以降解对硝基苯酚的游离氮位点。通过载体工程和功能性非金属位点的整合，该催化剂实现了高降解速率常数（0.12 min⁻¹）和出色的循环稳定性。阐明了PMS活化过程中不对称空位与游离N物种之间的协同催化机制。具体而言，尖晶石中的不对称氧与载体中的N键功能相结合，优化了费米能级附近的电子态，促进了更快的电子转移并增强了活性氧（ROS）的生成。不对称氧与吡咯氮位点之间的协同作用改善了PMS的吸附和活化，而氧与吡啶氮的组合使催化剂的d带中心降低了0.29 eV，促进了ROS的释放。此外，氧和吡咯氮协同增强了对硝基苯酚的吸附，使得表面ROS能够原位降解并加速降解动力学。这项工作不仅推动了催化剂中的缺陷工程，还揭示了“氧空位-氮协同”机制，为在复杂环境系统中设计多活性位点催化剂提供了有价值的见解。
