Morphology and Size Effect of Ceria Nanostructures on the Catalytic Performances of Pd/CeO₂ Catalysts for Methanol Decomposition to Syngas

Palladium is an active catalyst for the decomposition of methanol to syngas, and its chemical activity is largely affected by the interaction with the supporting substrate. Nanostructured cerium oxide can establish strong electronic interactions with finely dispersed palladium nanoparticles (NPs) leading to a substantial enhancement of their catalytic performance. To study this synergistic effect and connect it to structural parameters, we deposited Pd NPs on nanostructured cerium oxide particles exposing mainly the same (100) surface, but with different nanoshape and average dimension, and we have investigated their activity toward the methanol decomposition reaction. A systematic comparison of photoemission measurements taken at every step of the catalytic cycle allowed us to identify the most important factors that control the redox properties of the Pd/CeO₂ systems and therefore the overall catalytic activity. Capitalizing on this knowledge it was possible to synthesize synergistic nanocatalysts with an excellent chemical activity at very low temperature.