Tatarchuk Tetiana
Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387 Kraków, Poland.
Educational and Scientific Center of Materials Science and Nanotechnology, Vasyl Stefanyk Precarpathian National University, 76018 Ivano-Frankivsk, Ukraine.
Nanomaterials (Basel). 2024 Oct 12;14(20):1640. doi: 10.3390/nano14201640.
Spinel ferrites demonstrate extensive applications in different areas, like electrodes for electrochemical devices, gas sensors, catalysts, and magnetic adsorbents for environmentally important processes. However, defects in the real spinel structure can change the many physical and chemical properties of spinel ferrites. Although the number of defects in a crystal spinel lattice is small, their influence on the vast majority of physical properties could be really decisive. This review provides an overview of the structural characteristics of spinel compounds (e.g., CoFeO, NiFeO, ZnFeO, FeO, γ-FeO, CoO, MnO, NiCoO, ZnCoO, CoMnO, etc.) and examines the influence of defects on their properties. Attention was paid to the classification (0D, 1D, 2D, and 3D defects), nomenclature, and the formation of point and surface defects in ferrites. An in-depth description of the defects responsible for the physicochemical properties and the methodologies employed for their determination are presented. DFT as the most common simulation approach is described in relation to modeling the point defects in spinel compounds. The significant influence of defect distribution on the magnetic interactions between cations, enhancing magnetic properties, is highlighted. The main defect-engineering strategies (direct synthesis and post-treatment) are described. An antistructural notation of active centers in spinel cobalt ferrite is presented. It is shown that the introduction of cations with different charges (e.g., Cu(I), Mn(II), Ce(III), or Ce(IV)) into the cobalt ferrite spinel matrix results in the formation of various point defects. The ability to predict the type of defects and their impact on material properties is the basis of defect engineering, which is currently an extremely promising direction in modern materials science.
尖晶石铁氧体在不同领域有着广泛应用，如用于电化学装置的电极、气体传感器、催化剂以及用于环境重要过程的磁性吸附剂等。然而，实际尖晶石结构中的缺陷会改变尖晶石铁氧体的许多物理和化学性质。尽管晶体尖晶石晶格中的缺陷数量很少，但它们对绝大多数物理性质的影响可能是决定性的。本综述概述了尖晶石化合物（如CoFeO、NiFeO、ZnFeO、FeO、γ-FeO、CoO、MnO、NiCoO、ZnCoO、CoMnO等）的结构特征，并研究了缺陷对其性质的影响。重点关注了铁氧体中点缺陷和表面缺陷的分类（0D、1D、2D和3D缺陷）、命名法以及形成过程。深入描述了导致物理化学性质的缺陷及其测定方法。作为最常用模拟方法的密度泛函理论（DFT）与尖晶石化合物中点缺陷的建模相关进行了描述。强调了缺陷分布对阳离子间磁相互作用以及增强磁性的显著影响。描述了主要的缺陷工程策略（直接合成和后处理）。给出了尖晶石钴铁氧体中活性中心的反结构表示法。结果表明，将不同电荷的阳离子（如Cu(I)、Mn(II)、Ce(III)或Ce(IV)）引入钴铁氧体尖晶石基体中会导致形成各种点缺陷。预测缺陷类型及其对材料性质影响的能力是缺陷工程的基础，而缺陷工程目前是现代材料科学中一个极具前景的方向。
