Síntese da liga de Fe-Co pelo método de esferas híbridas utilizando Carboximetilcelulose como direcionador e sua aplicação em catálise

Abstract

Hybrid spheres is confirmed to be an efficient method in the synthesis of Fe-Co alloy. The carboxymethylcellulose-based organic precursor (CMC) was added dropwise to a solution containing Fe3+ and Co2+, leading to the formation of the hybrid spheres from the complexation of the metal cations with the radicals present in the biopolymer (crosslinking process). The hybrid spheres were calcined in air atmosphere leading to the formation of Fe and Co based oxide. After, it was reduced with H2 flow to form the FeCo alloy. The alloy was applied in the ethylbenzene dehydrogenation reaction to styrene production (high added value product). In order to characterize the obtained materials, it was used the infrared spectroscopy (FTIR), X-ray diffraction (XRD), temperature programmed reduction (TPR), thermogravimetric analysis (TG) and magnetometry (VSM). FTIR confirms the complexation mechanism between metal ions and CMC and the complete oxidation of the biopolymer after calcination. The diffractograms and TPR confirm the formation of the FeCo alloy after reduction under H2 atmosphere. TG indicates the minimum temperature at which the alloy is oxidized, confirming the chemical resistance of the FeCo alloy against the oxidizing atmosphere. The magnetic hysteresis curves confirm the ferromagnetic nature of the FeCo alloy. The ethylbenzene dehydrogenation reaction was selective for the formation of styrene, according to gas chromatography (GC), in the presence of the FeCo alloy, confirming the interesting properties of the iron-based catalysts for dehydrogenation reactions.