Preparation of CoZrxFe2-xO4 x Fe 2-x O 4 magnetic nanoparticles: In-depth investigation of Zr (IV) effect on photocatalytic performance, magnetic and electrochemical properties

In this work, we synthesize CoZrxFe(2_x)O4 x Fe ( 2 _ x ) O 4 nanoparticles by the co-precipitation method with different doping rates (x=0.0, =0.0, 0.04, 0.08, and 0.12) for the first time. X-ray diffraction (XRD) results revealed a pure phase, confirmed by Rietveld refinement, which validated the formation of a spinel structure with the Fd-3 m space group. The crystallite is found to be between 40 and 54 nm. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of the crystallographic sites of the spinel structure. Scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and energy dispersive X-ray spectroscopy (EDS) confirmed the morphology and homogeneity of the chemical composition. Through X-ray photoelectron spectroscopy (XPS), we identify the oxidation state of each ion and verify the presence of oxygen vacancy defects. Magnetic measurements confirmed the ferrimagnetic behavior of the prepared nanoparticles, with a dilution in the magnetic properties. The effect of increasing the Zr substitution on the impedance properties reveals a considerable increase in the total resistance, as well as the resistance of the grain interior and grain boundary. Photocatalytic degradation of the orange G dye under UV-Vis irradiation (300-800 nm) revealed activation of the nanoparticles by the doping effect, with efficiencies ranging from 9 % to 41.83 % after 60 minutes of exposure. DFT calculations were used to explain the observed improvement in photocatalytic degradation efficiency. These results highlight the good stability and high repeatability of the prepared nanoparticles, overcoming the challenges associated with recycling in photocatalytic applications.