Acido-basicity of lanthana/alumina catalysts and their activity in ethanol conversion

Lanthana on alumina samples (0.2, 0.8 and 4.7 theoretical monolayers) were prepared by incipient wetness impregnation using γ-Al2O3 as support. Characterization has been performed by BET, XRD, skeletal FT-IR, DR-UVvis, XPS, HR-TEM, IR spectra of the surface OH, adsorbed pyridine and CO2, and isopropanol TPD. Ethanol conversion was investigated both in temperature-programmed surface reaction (TPSR) dynamic conditions as well as in steady-state flow reactor tests. Lanthanum addition stabilizes alumina with respect to sintering and loss of surface area and La- containing phases are observed only for the high-La loaded catalyst. La-alumina catalysts are less active in ethanol dehydration than alumina but more selective to diethyl ether at partial conversion. 5%La2O3/Al2O3 is also equally or more selective than alumina to ethylene at high conversion, producing less carbonaceous material during reaction. Thus, this catalytic system might be a good candidate for (bio)ethylene production through (bio)ethanol dehydration.