Steam Reforming of Ethanol over Zn-Doped LaCoO3 Perovskite Nanocatalysts

Nanostructured LaCo1-xZnxO3 (x = 0, 0.05, 0.1, 0.2, 0.3 and 0.5) perovskites were synthesized by a one-step citric acid-complexing method for hydrogen production by the steam reforming of ethanol. For comparison, 8% CoO/ZnO and 8% CoO/La2O3 were prepared by impregnation and evaluated. The catalyst samples were characterized by X-ray diffraction, temperature-programmed reduction, and X-ray photoelectron spectroscopy. The results indicated that zinc did not favor the formation of the LaCo1-xZnxO3 perovskite and the structures of the substituted samples were less weakening than that of LaCoO3. Some segregation was observed for x ≥ 0.1. The reactivity of the studied samples was sensitive to the zinc content and lower substitution values were found to be better. An unexpected phase (Co3O4) appeared in the fresh LaCo0.9Zn0.1O3 sample. The presence of the Co3O4 phase increased the reactivity toward hydrogen production by the steam reforming of ethanol. The presence of La2O2CO3 is responsible for the low carbon deposition and the CH4 selectivity in the aged samples.