Influence of rhodium on the performance of lanthanum supported catalysts as NOx trapps

BÁRBARA S. SÁNCHEZ,; CARLOS A. QUERINI; EDUARDO E. MIRÓ

Salamanca, España

Congreso; EuropaCat IX: Catalysis for a Sustainable World; 2009

In this work lanthanum supported catalysts were investigated in relation to their performance as NOx trapps. The interaction between the catalysts surface and NOx was evaluated in gravimetric studies. Two cycles of NOx adsorption-desorption were carried out for each sample, in order to assess the reversibilty of the process over the different catalysts. It was found that, while over the K/La2O3 catalyst the NOx adsorption is an irreversible process, when rhodium is added to the formulation the species formed during the heating in NO+O2 became unstable. Moreover, this feature was observed even when rhodium was forming a mechanical mixture with the lanthanum supported catalyst. When the regeneration was carried out in a reducing atmosphere, decomposition was higher for all the solids studied. FTIR  spectra support information obtained in the microbalance experiments