RANEY COPPER-CATALYSTS FOR THE WATER-GAS SHIFT REACTION - I - PREPARATION, ACTIVITY AND STABILITY

Characterisation of partially leached Raney copper catalysts demonstra ted that the chemical nature of the reactant surface could be determin ed by controlling the leaching process. Initial water-gas shift (WGS) activity of the Raney copper catalysts at the stated conditions compar ed favourably to the co-precipitated and industrial catalyst alternati ves due to a similar active phase composition and high metallic copper surface areas. Raney copper catalyst deactivation in a poison-free en vironment was attributed to copper crystallite sintering, primarily as a result of a zinc oxide deficiency. Long term (850 h) stability of t he Raney catalyst is reported for the first time. Stability improved s ignificantly with increased ZnO loading as a result of better contact between the copper surface and ZnO crystallites. The stabilizing effec t of incorporated zinc was independent of its original source. The rol e of aluminium was to produce Raney copper of high surface area. No be neficial effects of residual alumina in the active catalysts were obse rved. (C) 1997 Elsevier Science B.V.