Glycerol conversion in the presence of ethanol over CoFe2O4/SBA-15 mesoporous catalyst: Effect of the co-reagent on the catalytic performance

Abstract

The synthesis and characterization of cobalt ferrite supported on mesoporous SBA-15 was presented to act as a catalyst in the glycerol conversion reaction in the presence of ethanol. Characterizations via X-ray diffraction (XRD) and FTIR spectroscopy confirmed the syntheses of SBA-15 and the CoFe2O4 phase dispersed on porous silica. Raman spectroscopy showed the ferrite with a degree of inversion (δ) of 0.4. The redox property was evaluated by TPR-H2 which exhibited reduction events above 400 °C, referring to the reduction of Co2+ and Fe3+ species. N2 physisorption analysis showed a surface area of 372 m2/g and a total pore volume of 0.65 cm3/g, indicating the presence of oxide on the surface and in the mesochannels of the support. Scanning electron microscopy (SEM) confirmed maintenance of support morphology after the impregnation process, while transmission electron microscopy (TEM) showed an average particle size of 6 nm for the supported cobalt ferrite. TEM images also confirmed that the typical mesoporosity of SBA-15 was maintained after spinel insertion. The acid-base properties of the catalyst indicated the presence of weak basic sites by CO2 temperature-programmed desorption (TPD-CO2) and the presence of Lewis acid sites by NO and Pyridine adsorption followed by FTIR analysis. The catalytic tests showed greater performance for the conversion glycerol in the presence of ethanol as co-reagent, considering that ethanol favors the interaction of glycerol with the solid surface and benefits the catalytic cycle. The reaction showed a conversion of only 20% in the absence of ethanol, while in the presence of the cosolvent a conversion greater than 80% was observed.