CHARACTERIZATION OF LI-DOPED NI/MGO CATALYSTS

The effects of the Li-doping on the reducibility and morphological properties of a Ni/MgO catalyst have been investigated by TPR, BET surface area, TEM, XPS, H-2, and CO chemisorption measurements. The roles of both the doping method (pre- and postimpregnation) and lithium loading (0.67-2.50 wt %) have been assessed. Lithium addition before calcination (preimpregnation) yields sintering of NiO, affecting the overall ''distribution'' of the Ni precursor across the MgO matrix. The promoting effect of Lif on the reducibility of the Ni/MgO system has been discussed. At high reduction temperatures (T-r greater than or equal to 600 degrees C), Li causes a collapse in the catalyst structure, resulting also in a dramatic sintering of the metal phase.