The carbon monoxide/nitrous oxide reaction. Kinetics of catalysis on TiO2 (anatase) and ZnO and activity correlations for the first-row transition metal oxides

The catalytic reaction between carbon monoxide and nitrous oxide on titanium dioxide (anatase) and zinc oxide has been examined in a continuous flow reactor at atmospheric pressure. The experimental activation energy was 144 ± 4 kJ mol−1 from 723 to 793 K on TiO2 and 121 ± 4 kJ mol−1 from 543 to 653 K on ZnO. Analyses of kinetic results indicated that a transient carbonate-like species may be involved in catalysis on both oxides. Relationships between the experimental activation energies for the CO/N2O reaction on first-row transition metal oxides and (i) activation energies for isotopic oxygen exchange, (ii) heats of carbonate formation, and (iii) the charge/radius ratio of the cation are interpreted in terms of the influence on catalysis of the cohesive properties of the metal/oxygen bonds in the oxide surfaces.