H2-SCR of NOx on low-SSA CeO2-supported Pd: The effect of Pd particle size

Abstract The H2-SCR of NO was investigated in the 130-220 °C range over low-SSA CeO2-supported Pd of varying particle size, dPd (ca. 13-45 nm). Relationships were derived between dPd and the specific integral rate (per gram of Pd or length of metal-support interface), NO conversion, N2-selectivity, TOFNO and the concentration of active NOx-s. The large enhancement in the rate of NO conversion per gram of Pd metal over the small Pd particles was found to be largely related to the increase in the concentration of active NOx formed within a zone around the Pd-ceria interface and the rate of H-spillover. The effect of H2O on the integral rate and N2-selectvity as a function of dp (nm) was also investigated.