Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, China and Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, I-20125 Milano, Italy.
Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, I-20125 Milano, Italy.
Nanoscale. 2021 May 27;13(20):9293-9302. doi: 10.1039/d1nr01014j.
Iron oxide magnetic nanoparticles (NPs) are excellent systems in catalysis and in nanomedicine, where they are mostly immersed in aqueous media. Even though the NP solvation by water is expected to play an active role, the detailed structural insight at the nanostructure oxide/water interface is still missing. Here, based on our previous efforts to obtain accurate models of dehydrated Fe3O4 NPs and of their magnetic properties and through multiscale molecular dynamics simulations combining the density functional tight binding method and force field, we unravel the atomistic details of the short range (chemical) and long range (physical) interfacial effects when magnetite nanoparticles are immersed in water. The influence of the first hydration shell on the structural, electronic and magnetic properties of Fe3O4 NPs is revealed by high-level hybrid density functional calculations. Hydrated Fe3O4 NPs possess larger magnetic moment than dehydrated ones. This work bridges the large gap between experimental studies on solvated Fe3O4 NPs and theoretical investigations on flat Fe3O4 surfaces covered with water and paves the way for further study of Fe3O4 NPs in biological environments.
氧化铁磁性纳米粒子（NPs）是催化和纳米医学中的优秀体系，它们大多沉浸在水相介质中。尽管预计纳米粒子的水溶剂化作用将发挥积极作用，但在纳米结构氧化物/水界面的详细结构洞察力仍然缺失。在这里，我们基于之前获得脱水 Fe3O4 NPs 及其磁性的准确模型的努力，并通过结合密度泛函紧束缚方法和力场的多尺度分子动力学模拟，揭示了当磁铁矿纳米粒子浸入水中时短程（化学）和长程（物理）界面效应的原子细节。通过高级混合密度泛函计算揭示了第一水合壳层对 Fe3O4 NPs 结构、电子和磁性的影响。水合 Fe3O4 NPs 具有比脱水的 Fe3O4 NPs 更大的磁矩。这项工作弥合了溶剂化 Fe3O4 NPs 的实验研究和覆盖有水的平面 Fe3O4 表面的理论研究之间的巨大差距，为进一步研究生物环境中的 Fe3O4 NPs 铺平了道路。
