Catalysts
Attempts to lower the reaction temperature of this reaction have been done primarily with a catalyst such as Fe3O4 (magnetite), or other transition metals and transition metal oxides. Another catalyst is the Raney copper catalyst.
The mechanism for the transition metal-catalyzed reaction can be generally understood as follows: a metal carbonyl complex (-CO) reacts with hydroxide to give a metallacarboxylic acid (-COOH−), which decarboxylates to give a metal hydride (-H−). Reaction with hydronium from water and carbon monoxide regenerates the metal carbonyl complex. The mechanism of decarboxylation is debated; it may involve β-hydride elimination, or it may require the action of an external base.
The water-gas shift reaction may be an undesired side reaction in processes involving water and carbon monoxide, e.g. the rhodium-based Monsanto process. The iridium-based Cativa process uses less water, which suppresses this reaction.
Read more about this topic: Water Gas Shift Reaction