Synthesis of Transition Metal Ferrites (Co, Cu, Ni, Mn) by the Sol-Gel Method with Combustion and the Use of Microwave Processing
This review considers recent work on the synthesis of transition metal ferrites (Co, Cu, Ni, Mn) by sol-gel method with combustion, as well as the effect of microwave radiation. Ferrites are interesting not only for magnetic and optical properties, but also for their catalytic ones. In recent years, there has been an increasing amount of literature, which investigates the catalytic properties of transition metal ferrites in various reactions, including oxidative reactions. Given the fact that various organic components are used as complexing agents and as a fuel in the sol-gel method with combustion, the review considers the influence of the organic reagent nature, its ratio to precursors, the pH of the medium, the power and time of microwave exposure to the process of ferrite formation as factors influencing the size of formed particles and their textural characteristics, which are of great importance in the catalysis. Recently, the attention of chemists working in the field of catalysis has been attracted by studies of the effect of physical fields, to which the microwave field belongs, on various chemical processes, including the nanocatalysts synthesis. The use of microwave radiation in sol-gel synthesis of ferrite allows obtaining nanoferrites with high specific surface area. From this point of view, this paper considers the works of recent years devoted to the study of microwave sol-gel synthesis of ferrite.