Ba,K,Co/CeO2 catalysts for NOx traps: Effect of preparation procedure Original Research Article

Ba,K,Co/CeO2 catalysts for diesel soot and NOx abatement were studied. Different preparation procedures were analyzed, varying the cobalt precursor and the order of their impregnation. The catalyst interaction with NO + O2 was studied using a microbalance and testing in both NO + O2 and He atmospheres. Fourier Transformed Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) were used to characterize the catalysts. The behavior of these catalysts as NOx traps was different. It was found that when cobalt nitrate was added to the Ba,K/CeO2 catalyst, a high NOx adsorption capacity was obtained and, what is even more interesting, that the decomposition of the nitrated species occurred at lower temperature. The identification by XRD of a perovskite BaCoO3 formed upon this preparation procedure was considered to be responsible for the different behavior observed in this particular catalyst.