Reaction mechanism of 1,2-dichlorobenzene oxidation over MnOX-CeO2 and the effect of simultaneous NO selective reduction

[Display omitted] •High ratio Mn/Ce improves activity due to good synergy achieved by Mn oxide phases.•A different distribution of products and intermediate occurs with temperature.•NO favours nitrate species that promote a faster re-oxidation of catalyst.•NH3 removes adsorbed Cl and reduces the production of chlorinated compounds. MnOX-CeO2 formulation has been studied for the catalytic oxidation of 1,2-dichlorobenzene. Among the samples with different Mn and Ce content, the most active was 85%mol Mn and 15%mol Ce, due to its better morphological properties and the synergy achieved between the two phases composing it (mixed oxide phase and segregated Mn oxide). Deactivation was monitored at low temperature and a transient change in the oxidative capability at high temperature because of active sites with different oxidative capability. Based on in-situ FTIR results, oxidation reaction pathway is proposed. Active sites with different oxidative capability causes some reaction steps to occur faster than others as a function of temperature, which modifies the distribution of intermediate species. In the reduction of NO, its adsorption leads to nitrate species contributing to a faster re-oxidation of active sites and the presence of NH3 promotes the removal of adsorbed Cl.