Chemically activated ruthenium mono(bipyridine)/SiO2 catalysts in water-gas shift reaction

Chemical activation of supported ruthenium mono(bipyridine) carbonyls was found to be an effective route to highly active water-gas shift catalysts. Catalysts were activated by treating silica supported [Ru(bpy)(CO)(2)Cl-2], [Ru(bpy)(CO)(2)ClH], [Ru(bpy)(CO)(2)Cl(C(O)OCH3)] or [{Ru(bpy)(CO)(2)Cl}(2)] with dilute NaOH or KOH solution. Ruthenium mono(bipyridine) carbonyls were deposited onto the support by impregnation from organic solvent or by pulse impregnation technique. In a typical experiment, catalysts achieved the final activity during WGS reaction. This induction period could be reduced by carrying out the hydroxide treatment under CO atmosphere. Catalytic activity was tested in the continuous flow WGS reaction at the temperature range 100-170 degrees C. The non-activated supported complexes showed at most moderate activity. Chemical treatment with NaOH or KOH solution increased the turnover frequency at the whole temperature range. The highest activities were obtained with NaOH treated [{Ru(bpy)(CO)(2)Cl}(2)]/SiO2, which gave turnover frequencies as high as 14500 (mol CO2 (Ru mol)(-1) (24 h)(-1)) at 150 degrees C. (C) 1998 Elsevier Science B.V. All rights reserved.