An Approach to the Optimization of Ba-Mn-Cu Perovskites as Catalysts for CO Oxidation: The Role of Cerium

Two copper-containing perovskites Ba_0.8Mn_0.7Cu_0.3O₃ and Cu(4 wt%)/Ba_0.7MnO₃ (selected from previous studies) were tested as catalysts for the CO oxidation reaction under conditions similar to the found in the exhaust of last-generation automotive internal combustion engines. The Cu(4 wt%)/Ba_0.7MnO₃ sample has been selected due to its higher tolerance to CO₂. In order to optimize the performance of this sample for the reaction under study, a Cu(2 wt%)Ce(2 wt%)/Ba_0.7MnO₃ formulation was synthesized, characterized and tested. The excellent catalytic performance of the bimetallic formulation, in terms of CO conversion at low temperatures and tolerance to CO₂, is because cerium improves the redox properties and increases the proportion of reduced copper species on the surface compared to the Cu(4 wt%)/Ba_0.7MnO₃ sample.