Pd/CeO2-SnO2 catalysts with varying tin content: Promotion of catalytic properties and structure modification

Abstract

1%Pd/CeO2-SnO2 catalysts with varying Ce/Sn ratio were synthesized by counter-precipitation followed by calcination in a wide temperature range. The catalysts with Ce/Sn < 3/1 possess high thermal stability after calcination up to 1000 °C while maintaining low-temperature activity in CO oxidation. The PdOx clusters serving as active centers in CO oxidation are modified by Sn upon calcination. High tin content (Ce/Sn = 1/3) provides the activity of the catalysts in CH4 oxidation due to stabilization of PdO nanoparticles in the form of core@shell PdO@(CeO2 + SnO2) structures. Formation of the nanoheterophase structure upon calcination plays a key role in the stabilization of Pd-active centers of different types.