Study of Au-CeO2 Nano-particles using analytical Transmission Electron Microscopy

Abstract

Cerium oxide doped with various rare earth metals is often used as a support for nano-sized gold particles, and demonstrates to be a promising catalyst for the water gas shift reaction at low temperatures. Many factors are hypothesized to affect the activity of this heterogeneous catalyst, including its loading with gold, the rare-earth dopant, the support and Au particle size, and leaching of the sample. In this study, we examined several Au/CeO 2 -based catalyst samples, including 2.4% Au/(Ce,Gd)O 2 , 1.8% Au/(Ce,La)O 2  leached, 0.5% Au/(Ce,Gd)O 2  leached, and 0.75% Au/CeO 2  utilizing analytical transmission electron microscopy. The effects of Au and rare-earth doping on the ceria lattice parameter were investigated, and it was determined that there are no significant variations in the particle's structure or lattice-spacing. Furthermore, the particle sizes of each of the four samples were investigated concluding that although the 1.8% Au/(Ce,La)O 2  leached sample has a slightly larger particle size, and the 2.4% Au/(Ce,Gd)O 2  sample has a slightly smaller particle size, the differentiation is not adequate to be accountable for the radical distinction in catalytic activity.