Nickel catalysts promoted with lanthanum for ethanol steam reforming: Influence of support and treatment on activity

The effect of support nature on the catalytic performance of Ni-based catalysts for ethanol steam reforming (ESR) was investigated. Nickel catalysts supported on lanthanum-modified Al2O3, TiO2, Al2O3-TiO2 and Al-pillared bentonite (denoted as Clay) were prepared by impregnation, characterized by X-ray diffraction (XRD), N2 adsoption-desorption, IR spectroscopy of acetonitrile adsorption and thermogravimetric analysis (TGA), and evaluated at 500 ?C under atmospheric pressure. Both Ni/La-Al2O3 and Ni/La-TiO2-Al2O3 exhibited the best stability, whereas Ni/La-TiO2 and Ni/La-Clay deactivated quickly but with similar or higher H2 production. Catalyst deactivation was caused by carbon deposition, which formation was related to strong Br?nsted sites. Efficiency of lanthanum as inhibitor of carbon deposition depended on the support nature. Oxidative regeneration allowed recovering initial activity of all used catalysts and even improving the performance of the latter two catalysts. This unexpected improvement can be due to change of nickel centres nature, caused by local overheating during the deposited carbon combustion.

Automated summary

The study investigated the effect of support nature on the catalytic performance of Ni-based catalysts for ethanol steam reforming, finding that Ni/La-Al2O3 and Ni/La-TiO2-Al2O3 showed the best stability, while Ni/La-TiO2 and Ni/La-Clay deactivated quickly but with increased H2 production. Catalyst deactivation was mainly caused by carbon deposition, and the efficiency of lanthanum as inhibitor of carbon deposition depended on the support nature. Oxidative regeneration allowed recovering initial activity of all used catalysts and even improving the performance of the latter two catalysts, possibly due to change of nickel centres nature caused by local overheating during the deposited carbon combustion.