Effect of acidity on ferric oxide nanoparticles supported on γ-χ-Al2O3 in the methanol dehydration reaction toward dimethyl ether

In this work, the low cost synthesis of the Fe2O3/????Al2O3 catalyst, carried out by the wet impregnation method, promoted a conversion in methanol dehydration by 46% (an increase of 5% with respect to ????Al2O3 support), and with a selectivity of 100% towards DME (at 250 ?C and 1 atm pressure), due to a higher abundance in the density of moderate acidic sites generated by the synergistic metal-support interaction. The slight decrease in catalytic activity for the Fe2O3/????Al2O3 system, compared to the ????Al2O3 from 260 ?C, was linked to the effect of changes in the shape and size of the Fe2O3 nanoparticles. These particles went from semi-spherical to nano-needles at 290 ?C reaction temperature. Finally, the great structural stability of Fe3+ measured by XPS, RAMAN spectroscopy and UV?Vis, and the low activation energy of the Fe2O3/????Al2O3 material (102.66 kJ/ mol), place the Fe2O3/????Al2O3 catalyst as an excellent candidate for methanol dehydration, under conditions of 240 to 250 ?C and methanol partial pressures between 9.8 and 7.8 kPa, respectively.

Automated summary

In this study, a low-cost synthesis method was used to prepare the Fe2O3/????Al2O3 catalyst, which showed a significant improvement in methanol dehydration conversion rate and selectivity towards DME. The Fe2O3/????Al2O3 catalyst exhibited a stable structure and low activation energy, making it a promising candidate for methanol dehydration under specific conditions.