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A novel synthesis route driving redox-precipitation reactions among MnVII, CeIII, and MnII precursors in basic aqueous solution yields MnCeO x catalysts (Mnat/Ceat, 0.33−2.0) with a (quasi)molecular dispersion of the active phase and enhanced textural properties in comparison to the conventional coprecipitation method. The basic characteristics of the redox-precipitation process leading to a solid architecture missing a substantial “long-range” crystalline order are discussed. With an excellent reproducibility and irrespective of the Mnat/Ceat ratio, the redox-precipitation method also ensures unchanged textural, structural, and chemical properties of the MnCeO x catalysts. As a much improved dispersion of the active phase, the redox-precipitation route greatly promotes the redox behavior and the surface affinity toward gas-phase oxygen of the MnCeO x system.

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The effects of chemical composition, calcination temperature, and the addition of potassium on the physicochemical properties and reactivity of MnCeO x systems in the catalytic wet oxidation (CWO) of phenol with oxygen (T R ) 373 K; P R ) 1.0 MPa; w cat /w phenol ) 5) have been addressed. Characterization data of "fresh" and "spent" catalysts signal the occurrence of a typically heterogeneous reaction path, the surface reaction between the adsorbed intermediate(s), and activated oxygen species being the rate-determining step (rds). Basic relationships among structural properties, the redox pattern, and CWO activity provide evidence of the main catalyst design requirements. A new synthesis route based on the redox-precipitation reactions of various Mn and Ce precursors then yields MnCeO x catalysts with improved physicochemical features and superior CWO activity, in comparison to conventional coprecipitated systems.