A definitive assessment of the CO oxidation pattern of a nanocomposite MnCeOx catalyst

The CO oxidation pattern of a nanocomposite MnCeOx catalyst (M5C1; Mn-at/Ce-at, 5) in the range of 293-533 K (P, 1 atm) has been probed under a kinetic regime, varying reagent pressure (p(CO)(0), 0.01-0.025 atm; lambda(0), 1), p(CO)(0/)p(O2)(0) ratio (lambda(0), 0.25-4.0) and CO2 co-feeding (0.05-0.10 atm). Activity data indicate fractional orders on p(CO) (0.6 +/- 0.1) and p(O2) (0.4 +/- 0.1), with an activation energy of 40 +/- 3 kJ mol(-1), and a negative kinetic effect of CO2 co-feeding due to competitive adsorption processes. Coupled with systematic evidence on the reactivity and mobility of catalyst oxygen and surface intermediates, kinetic data disclose a concerted redox mechanism of Langmuir-Hinshelwood type, which starts by abstraction of O-atoms from surface active Mn-IV centres (r.d.s.), and is sustained by adsorption of diatomic oxygen species on O-vacancies. The derivative and integral forms of the formal rate equation explain the empirical kinetics, predicting the activity pattern of the MnCeOx catalyst in the range of 293-533 K.