Effect of lanthana addition on cobalt based catalysts for hydrogen production via ethanol steam reforming

FERREIRA, NICOLÁS; LAURA CORNGALIA; JOHN MÚNERA

Santa Fe

Conferencia; VI San Luis Conference on Surfaces, Interfaces and Catalysis; 2018

Universidad Nacional del Litoral

In this work, Co based catalystssupported on lanthana-silica binary oxides were synthetized by incipientwetness impregnation, varying the La2O3 composition from0 to 50 wt.%. The samples were characterized by several techniques (XRD, TPR,Raman, XPS) in order to elucidate the catalyst properties and correlate themwith their catalytic behavior. The Co3O4 spinel waspresent and the appearance of the La2SiO7 phase wasobserved as the lanthanum concentration increased. In addition, a strongmetal-support interaction was identified. The low surface composition of theactive metal determined by XPS can be attributed to the impregnation method, aswell as the high metal loading decreasing the surface dispersion of the metal.Moreover, a combination of oxidation states (Co+3, Co+2and Co0) was found in the surface after exposing the samples to a H2flow at 500 °C. The performance of the solids for the ethanol steam reformingreaction was investigated in a conventional fixed-bed reactor at 500 °C with awater/ethanol molar rate (R=5), using 20 mg of catalyst diluted in 70 meshquartz (1:3). The catalytic results showed that for the best catalysts (with aLa2O3 composition of 15 and 20 wt.%) hydrogen was the mainproduct, while the CO concentration was below 10 %. The addition of La2O3improves catalysts stability, but concentrations of La2O3above 20 wt.% on the catalyst support, decreased the hydrogen selectivity.Similar results were obtained for catalyst supported on bare La2O34,demonstrating the influence of the support on the selectivity towardsacetaldehyde, decreasing hydrogen yield.