Glycerol steam reforming over Ru-Mg-Al hydrotalcite-derived mixed oxides: Role of the preparation method in catalytic activity

Ru-Mg-Al hydrotalcite-derived mixed oxides were synthesized using two preparation methods. The grafted catalyst was prepared by co-precipitation of the Ru/Mg/Al precursors at a constant pH. The impregnated catalyst was prepared by wet-impregnation of a calcined Mg-Al support with the Ru precursor (Ru(NO) (NO₃)₃). Both catalysts were calcined at 600 °C and characterized by X-ray diffraction, CO₂- temperature programmed desorption and H₂-temperature programmed reduction techniques. Catalytic activities were compared in the glycerol steam reforming reaction (400–700 °C, WGFR 9:1, flow rate: 0.075 ml/min) followed by a short-term stability test at 600 °C. The impregnated catalyst demonstrated a superior activity beyond 600 °C. This difference in activity was attributed to the easier accessibility of the active phase resulting from the preparation method. Short-term stability tests revealed deactivation of both catalysts as a result of coke formation.