Abstract
<jats:p>Ferrites are ferrimagnetic iron-oxide–based materials whose magnetic and functional properties are governed by cation distribution, defects, and microstructure, all of which are strongly affected by synthesis. This review focuses on spinel copper ferrite (CuFe2O4) nanoparticles, emphasizing how synthesis-controlled structure determines multifunctional performance. Particular attention is given to the coexistence and stabilization of tetragonal and cubic CuFe2O4 phases, the role of Jahn–Teller distortion of Cu2+, and the influence of oxygen nonstoichiometry, cation redistribution, and surface disorder in the nanoscale regime. The most widely used chemical routes – co-precipitation, hydrothermal/solvothermal synthesis, and sol–gel (including autocombustion) – are discussed with respect to their ability to control phase purity, crystallinity, particle size, morphology, and defect chemistry. The structure–property framework is then linked to key application domains covered in this work: visible-light-driven photocatalytic degradation of dyes, adsorption-based removal of pollutants, photocatalytic hydrogen evolution, electromagnetic interference shielding/microwave attenuation, and functional sensing platforms. Finally, practical limitations are summarized, including reproducibility of cation/defect states, phase stability, performance degradation, and regeneration, highlighting the need for standardized evaluation protocols and rational materials design for scalable, reusable CuFe2O4-based technologies.</jats:p>