Multifunctional Cobalt Ferrite Nanocomposites: Synthesis Methods and Prospects in Environmental, Medical and Energy Storage Fields

Cobalt ferrite (CoFe₂O₄) nanoparticles (NPs) have become one of the most extensively studied spinel ferrites due to their remarkable physicochemical characteristics, such as high magneto crystalline anisotropy, excellent coercivity, notable chemical stability, adjustable optical band gap (1.3–1.9 eV), and significant saturation magnetization (50-80 emu/g). These inherent properties, further improved through cationic substitution and the formation of nanocomposites, make CoFe₂O₄ NPs highly adaptable for a wide range of technological uses. This review offers a thorough and up-to-date examination of the synthesis, structural characteristics, effects of elemental substitution, and various applications of CoFe₂O₄ NPs and their nanocomposites (NCs). The primary synthesis methods such as co-precipitation, sol-gel auto combustion, microemulsion, solvothermal, hydrothermal, and ceramic techniques are thoroughly assessed regarding control over particle size, level of crystallinity, and scalability. The effect of replacing main group elements, first and second transition series metals, and lanthanides on the structural, magnetic, electrical, and catalytic characteristics of CoFe₂O₄ is examined in detail. Various characterization techniques including XRD, FTIR, SEM/TEM, VSM, BET, and XPS are described to clarify the relationships between structure and properties. The applications assessed include environmental remediation techniques, biomedical applications, and energy storage solutions. The review highlights that strategic design of nanocomposites and precise substitution are essential methods for tackling the inherent drawbacks of unmodified CoFe₂O₄ and realizing its complete multifunctional capabilities.