Effect of interaction degree between Mn and Ce of MnOX-CeO2 formulation on NO reduction and o-DCB oxidation performed simultaneously

Abstract

MnOX-CeO2 catalysts were prepared by different methods in order to assess the influence of Mn and Ce interaction on the catalytic activity of NO reduction and 1,2-dichlorobencene (o-DCB) oxidation carried out simultaneously. Changes on catalytic properties were evaluated by XRD, Raman, N2-physisorption, H2-TPR and NH3-TPD. The samples prepared by co-precipitation and sol-gel exhibited the best catalytic activity over the whole temperature range. These preparation methods provide high interaction between Mn and Ce at surface and bulk, which was evidenced by the formation of mixed oxide phase. According to characterisation, the enhancement of catalytic activity with Mn and Ce interaction is associated to the promotion of structural defects, which improve redox and acid properties. Oxidative capability is also improved as a consequence of the oxygen vacancies generated by the presence of those structural defects. On the other hand, the promotion of Mn and Ce interaction favours the production of N2O in NO reduction at a lower temperature, and also leads to o-DCB total oxidation by decreasing CO production.