Influence of the fuel composition and the fuel/oxidizer ratio on the combustion solution synthesis of MgFe2O4 catalyst nanoparticles

Abstract

Solution combustion synthesis (SCS) has been widely applied to produce oxide catalysts due to the possibility of producing highly pure and homogeneous nanostructured powders at low cost. The smaller the particles are and the higher the surface area is, the more efficient the powder catalyst will be. For iron-based catalysts such as ferrites, the degree of spinel inversion is another factor that affects the catalyst activity. In SCS, the particle size, surface area, and degree of spinel inversion are fundamentally related to process variables such as the fuel composition and the fuel/oxidizer ratio. Therefore, we studied the application of glycine and polyethylene glycol-200 molecular weight (PEG 200) as fuels and the influence of the fuel/oxidizer ratio in the SCS of MgFe 2 O 4 catalyst nanoparticles. The products' morphology and composition were systematically characterized by X-ray diffraction, microscopy analyses, and specific surface area. The results indicate the production of high-purity nanoparticles with increased surface area, which was obtained with low concentrations of glycine and a wide range of particle sizes that depend on the fuel composition and concentration.

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

“…In turn, a change in the redox environment is possible both by choosing various types of reducing agents (glycine, urea, citric acid, etc.) and oxidizing agents (nitrates, perchlorates, oxalates), and by varying the amount of fuel involved in the reaction [26]. At a stoichiometric ratio of the oxidizing agent to the reducing agent (G / N =0.6), the oxidation proceeds completely without atmospheric oxygen, whereas in the case of excess (G / N > 0.6) or lack of fuel (G / N < 0.6), it takes an active part in the process.…”