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.

Carbon nanotubes (CNTs) are studied because of their diverse applications in many fields, such as medicine, computing, physics, chemistry, and others. Therefore, it is crucial to develop techniques for producing a large volume of high-quality multi-wall carbon nanotubes (MWCNTs) with the best cost-to-benefit ratio. In this paper, we obtain MWCNTs via an arc-electric alternative route, which dispenses catalysts and sealed cameras using water as an insulating medium. This method is simple, cost-effective (starting from pieces of commercial graphite pencil), efficient, and highly reproducible. Since no catalysts are used, no purification post-treatment was necessary, leading to high-quality MWCNTs. This technique is very promising for industrial applications because a lot of high-quality MWCNTs could be easily produced in a short time.