Probing the functionality of nanostructured MnCeOx catalysts in the carbon monoxide oxidation Part II. Reaction mechanism and kinetic modelling

The kinetics of the CO oxidation on a typical nanocomposite MnCeOxcatalyst (M5C1) were probed by tem-perature programmed catalytic reaction (TPCR) tests in the range of 293–533 K, varying reagent partialpressure (i.e., pCOand pO2) between 0.00625 and 0.025 atm (P, 1 atm) (Arena et al., 2017). Experimentaldata indicate kinetic orders of 0.6 and 0.4 on pCOand pO2respectively, with apparent activation energy of40 ± 3 kJ/mol (Arena et al., 2017). A systematic study of the interaction pattern of catalyst with reagentand product molecules shows easy reactivity of surface oxygen to CO, low mobility of lattice oxygen andweak surface affinity to CO2. Systematic evidences on reaction mechanism and surface intermediatessignal an extrafacial redox path, triggered by abstraction of oxygen atoms in the neighbouring of activeMnIVsites (Arena et al., 2017), and sustained by O2species adsorbed on those surface oxygen vacancies.A Langmuir-Hinshelwood (L-H) reaction mechanism leads to a formal kinetic model explaining the COoxidation functionality of bare and promoted MnOxcatalysts.