Composition-Dependent Chlorobenzene Oxidation over Co–Ce–Pr Oxides: Mineralization and Oxygen-Release Behavior

Deep oxidation of chlorobenzene (CB) requires continued conversion of its intermediates to CO2. Across Co–Ce–Pr mixed oxides (Co8, Co16, and Co32), Co16 achieved 98% CO2 mineralization at 300 °C, substantially outperforming Co8 and Co32 despite smaller differences in CB conversion. The main composition effect appeared in the further oxidation of converted carbon. Co16 had the largest surface area and the strongest oxygen desorption response. It maintained conversion above 80% during a 10 h continuous test. Higher water concentrations caused stronger inhibition, with substantial activity recovery after removal of 5% and 10% H2O. Compared with Co8, Co16 produced less o-dichlorobenzene throughout the measured temperature range, but more p-dichlorobenzene at 275–325 °C.