ALKALI-METAL PROMOTED RANEY COPPER-CATALYSTS FOR THE WATER-GAS SHIFT REACTION

The promotional effect of the addition of caesium, potassium and rubid ium to the water-gas shift activity of a Raney copper catalyst of comp osition 34.3% Cu, 10.9% Zn and 54.8% Al has been investigated. Concent rations of less than 0.1% alkali metal ions resulted in increases in t he BET surface area, but a decrease in the Cu surface area of the Rane y copper catalyst. The addition of 0.035 mol% Cs to the Raney copper c atalyst was found to enhance the catalyst's water-gas shift activity. Concentrations in excess of 0.28 mol% showed no promotional benefits. Evidence suggested that the alkali metal ions are directly involved in the water-gas shift mechanism over promoted Raney copper catalysts.