Synthesis and characterization of CuFeS₂ particles by conventional hydrothermal and microwave-assisted hydrothermal methods

Full text: Chalcogenides compounds have attracted much attention in recent years due to their physical and chemical properties. Among them, CuFeS₂ is a semiconductor that belongs to the secondary chalcogenide family and has optical, electrical and magnetic properties, such as a very small optical absorption edge (0.5–0.6 eV). CuFeS₂ has potential for practical applications, including the conversion of solar energy, photocatalysis, lithium batteries and chemical and biological sensors. The unique structure of CuFeS₂ with complex oxidation states, including Cu⁺, Cu²⁺, Fe²⁺ and Fe³⁺, allows for highly effective electron transfer on the surface of and inside the CuFeS₂ crystals. In this work, CuFeS₂ nanoparticles were successfully synthesized by two methods of synthesis: conventional hydrothermal and microwave-assisted hydrothermal, with the main objective of studying the properties of formed materials. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), BET surface area and particle size distribution. X-ray diffraction showed the formation of single-phase CuFeS₂ structure, with elongated and well-defined peaks and, without the presence of secondary phases for both synthesis routes. The obtained material by the hydrothermal method presented higher crystallinity and crystallite size, while the obtained material by hydrothermal microwave assisted route presented peaks of lower intensity. The micrographs exhibit uniform crystals with circular morphology for both routes. The EDS analysis revealed that the CuFeS₂ synthesized by the different routes have consistency with the stoichiometric composition of 1: 1: 2. The specific surface areas (BET) revealed a larger surface area and higher volume of pores for CuFeS₂ synthesized by hydrothermal microwave-assisted method. Therefore, the two synthesis routes employed in this work proved to be satisfactory for the production of pure CuFeS₂. (author)