Synthesis of Zinc Ferrite Ferrofluids for Energy Harvesting Applications

The synthesis of Zn x Fe 3‐x O 4 nanoparticles was carried out by a simple coprecipitation method and converted into ferrofluids by adding TMAH as a surfactant and H 2 O as a carrier liquid. The successful synthesis of Zn x Fe 3‐x O 4 nanoparticles using the coprecipitation method with a concentration of x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5 was proven by the shift of the diffraction peak toward a smaller angle due to the substitution of Zn 2+ , which has a bigger ionic radius than that of Fe 3+ , increasing the lattice parameters. Based on the SEM‐EDX analysis results, the particle sizes of the Zn x Fe 3‐ x O 4 nanoparticles were in the range of 10.2–27.2 nm, which decreased as Zn composition increased. In addition, an increase in the Zn composition for a large x value was detected, and the appearance of a Zn‐O vibration peak in the FTIR spectrum was observed at a wavenumber of 650 cm −1 . Furthermore, the UV‐Vis data analysis suggested that the band gap energy of the samples decreased the dielectric constant. While previous research has investigated zinc ferrite nanoparticles, this study contributes to the application of synthesizing these particles into a stable, TMAH‐coated ferrofluid specifically formulated to act as an active liquid magnetic core for electromagnetic energy harvesting. Analysis of energy harvesting based on Zn x Fe 3‐ x O 4 ferrofluids resulted in higher output voltage from 2.77 to 27.15 V, linear to the increasing Zn composition. Thus, the Zn x Fe 3‐ x O 4 ferrofluids obtained from this research can be developed as new materials for energy harvesting systems.