Magnetic and electrochemical characterization of magnetite nanoparticles modified with tetrahydroxyquinone

This study presents a method for synthesizing superparamagnetic nanoparticles through the co-precipitation method, with a coating of tetrahydroxy-1,4-quinone (THQ). The diameter of the magnetite nanoparticles (MNPs) covered with THQ varied depending on the recovery method applied. When collected through magnetic decantation, they exhibited an average diameter of 15 ± 3 nm, while centrifugation of the supernatant further reduced the diameter to 12 ± 3 nm. In contrast, the uncoated MNPs had an average diameter of 17 ± 5 nm. The smaller MNPs coated with THQ displayed very low magnetic hysteresis and demonstrated superparamagnetic behavior, indicated by a blocking temperature of less than 300 K. Characterization of both the coated and uncoated MNPs encompassed structural, morphological, size, and magnetic property analyses using X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. Fourier-transform infrared spectroscopy (FT-IR) and UV–Vis spectroscopy were employed to investigate the chemical interaction between THQ and the MNPs. In addition, cyclic voltammetry was used to compare the electrochemical changes of THQ, MNPs, and MNPs coated with THQ.