ON THE ACTIVATION-ENERGIES OF THE FORWARD AND REVERSE WATER-GAS SHIFT REACTION

Published experimental results demonstrate that the reverse water-gas shift reaction is surprisingly fast over several varied catalysts (metallic and oxidic). The observed values of activation energy of the reaction are shown here to be inconsistent with values calculated from the standard enthalpy change and the activation energies of the forward reaction. Possible explanations of this paradox are discussed in terms of the limits to the application of the ''principle of microscopic reversibility'' to catalytic systems.