Synthesis and characterization of Rh and RhOx particles supported on zeolites with high activity of lean NOx–CO–H2 reaction

Rh and RhOx nanoparticles supported on zeolites were synthesized in a hydrothermal process using a gel mixture of zeolite and Rh precursors. The morphology of the nanoparticles was varied depending on the kind of zeolite and synthesis conditions. Samples were characterized with XRD, TEM, CO chemisorption and BET analysis. In the hydrothermal process, the nanoparticles were loaded on Na-beta zeolite and Na-ZSM-5 in the form of dispersed particles and agglomerated particles, respectively. The nanoparticles supported on Na-ZSM-5 more efficiently catalyze NOx reduction in lean conditions using hydrogen and CO as a main reductant than those supported on Na-beta zeolite.