Effect of Ag loading on praseodymium doped ceria catalyst for soot oxidation activity

Abstract

Silver-loaded praseodymium doped ceria (XAg/PDC) was synthesized by microwave-assisted co-precipitation and wetness impregnation. XRD confirms the fluorite structure of ceria without secondary phase, and Raman spectroscopy represents the increased generation of oxygen vacancies with Ag loading. The TEM analysis shows lattice fringes corresponding to both CeO<inf>2</inf> and Ag on the surface. The BET and BJH analysis of catalyst confirms the high porosity accompanied by high surface area and pore diameter of 5Ag/PDC and 15Ag/PDC, making it more active for the oxidation reaction. From the XPS analysis the amount of surface Ce3+ concentration and the surface chemisorbed oxygen species (O<inf>2</inf> 2) is high for 5Ag/PDC and 15Ag/PDC, in line with XRD and Raman results. The soot oxidation T<inf>50</inf> temperature follows the trend: 5Ag/PDC∼15Ag/PDC<10Ag/PDC<20Ag/PDC<0Ag/PDC. The Ag loading increased the surface reducibility of cerium ions and thus 5 wt% was optimized. © 2021, The Korean Institute of Chemical Engineers.