WATER-GAS SHIFT REACTION - FINDING THE MECHANISTIC BOUNDARY

The mechanism of the water-gas shift reaction is discussed for both co pper/zinc oxide/alumina and iron oxide/chromium oxide catalysts. The a ssociative and regenerative mechanisms are presented and the evidence concerning each mechanism is critically reviewed. It is concluded that for the low temperature shift reaction over copper/zinc oxide/alumina catalysts considerable evidence exists to support both mechanisms and it is possible that either could proceed on the catalyst surface. For the iron oxide/chromium oxide catalysed high temperature shift reacti on the experimental evidence supports a regenerative mechanism.