Detailed study of enhancing the electrical, optical, and photodegradation properties of MnZn/CdZn spinel ferrite core/shell nanostructures

In this study, Mn_0.7Zn_0.3Fe₂O₄/Cd_xZn_1-xFe₂O₄ core/shell samples were synthesized by the hydrothermal method by varying the Cd²⁺ content from x = 0.1–0.3 in the shell. Structural, electrical, optical, and photocatalytic properties of the core/shell were analyzed based on various Cd²⁺ contents in the shell. The structural behavior of the nanoparticles was studied by the X-ray diffraction technique, and it was found that core/shell samples were cubic structures with single-phase core/shell structures. The effect of the Cd²⁺ content in the shell was clarified by calculating lattice parameters, microstrain, and crystallite size. The elemental compositions were confirmed by EDX. Electrical properties, such as AC conductivity, dielectric constant, and tangent loss, were measured using an LCR meter. The results showed that with increasing Cd²⁺ content, electrical conductivity decreased. Based on the experimental results, different numerical techniques were used to determine the optical gap and refractive index for the core/shell samples, and when the Cd²⁺ content increased, the band gap value of samples S1 and S2 decreased but increased in S3, while the refractive index increased for S1 and S2 and decreased in S3. Furthermore, photoluminescence spectrum shows that core/shell ferrite nanoparticles have much stronger and tunable than bare ferrite due to altered electron–hole recombination at the heterojunction interface. The Mn_0.7Zn_0.3Fe₂O₄/Cd_xZn_1 − xFe₂O₄ core/shell NPs were later found to be effective under visible light irradiation, which demonstrated a maximum reduction (95%) of methylene blue (MB) in a neutral environment for x = 0.3. The correlation between the Cd²⁺ content, structural, electrical, optical parameters, and photocatalytic efficacy is explained in detail.