Eco‐Friendly Transformation of Bioethanol into Ethylene over Bimetallic Nickel‐Copper Catalysts

Abstract

AbstractThe conversion of bioethanol to ethylene in gas phase and atmospheric pressure was investigated over γ‐Al2O3 supported copper and nickel catalysts. These catalysts were prepared by co‐precipitation and pre‐treated with hydrogen at 450 °C. Six catalysts were studied at 450 °C under a nitrogen atmosphere. It was found that the monometallic Cu/γ‐Al2O3 catalyst exhibited the highest ethylene concentration, with a selectivity of around 90 %. The bioethanol conversion obtained was between 57 %‐86 %. Another catalyst that exhibited high concentration values was the NiCu1 : 7 bimetallic catalyst. The catalysts were characterised using XRD, SEM, EDS, TEM, TGA, FTIR, Raman, and N2‐physisoption techniques. Furthermore, the Cu/γ‐Al2O3 catalyst was studied under different reduction temperatures and gas flow conditions. It was found that the catalysts reduced at 350 °C and 35 ml/min N2 flow presented ethylene concentrations between (0.18–0.21) g/L. Moreover, the catalyst deactivation was identified to be first order and the equation of the Cu/γ‐Al2O3 catalyst deactivation model was determined. Carbonaceous deposits over the used sample were not detected by Raman and FTIR. It was determined that the Cu/γ‐Al2O3 catalyst deactivation could be mainly attributed to the blocking of the catalytic sites by strongly adsorbed compounds and hydroxylation of the catalyst surface.