Surface engineering of nano-ceria facet dependent coupling effect on Pt nanocrystals for electro-catalysis of methanol oxidation reaction

Surface engineering of metal-support coupling interaction is significant in the catalytic reactions. Herein, we demonstrate a nano-ceria facet dependent coupling effect on Pt nanocrystals for the electro-catalysis of methanol oxidation in acid electrolyte for fuel cell reaction. It is found CeO2 exposed with different facets have different Pt nanocrystals trapping/coupling ability, and this interplay induces the different surface chemical states of Pt and Ce in terms of the content of Pt(0) and Ce3+, Pt-O-Ce bonding, the oxygen vacancy and electronic states. The CeO2-rods enclosed by (1 1 0) and (1 0 0) facets coupled Pt nanocrystals show much higher catalytic activity and durability than that of CeO2-plates and CeO2-cubes exposed by (1 1 1) and (1 0 0) facets respectively. Specifically, Pt-CeO2-rods exhibit a specific activity of 2.04 mA cm(-2), nearly 1.5 and 2.6-fold enhancement than that of Pt-CeO2-cubes and Pt-CeO2-plates. Facet-dependence anti-poisoning and stability are also discovered after 8000 cyclic voltammetry cycles on the proposed catalyst. The weakened poisoning intermediates adsorption ability via bi-functional mechanism and the metal-support interaction induced by different CeO2 support can account for the facet-dependent methanol electro-oxidation performance on Pt-CeO2 catalyst system. The current work demonstrates the significance of assistant catalyst facet/morphology tuning in the fuel cells catalyst design and fabrication.