Production of CO from CO2 by reduced indium oxide

The forward and backward reactions of the process ln2O3(s)+xCO(g)⇌ ln2O3–x(s)+xCO2(g) proceed rapidly and repeatedly at 673 K when the degree of reduction of ln2O3 is low. However, the yield of the backward reaction decreases as the degree of reduction rises above ca. 40%. This is ascribed to a decrease in the number of surface-active sites for the decomposition of CO2. The free-energy change of the reaction evaluated from the ratio of partial pressures P(CO2)/P(CO) at equilibrium agreed well with results obtained by other workers, assuming indium metal as the reduced species.