Simple replacement reaction for the preparation of ternary Fe _1-xPtRu _x nanocrystals with superior catalytic activity in methanol oxidation reaction

The finding of new metal alloyed nanocrystals (NCs) with high catalytic activity and low cost to replace PtRu NCs is a critical step toward the commercialization of fuel cells. In this work, a simple cation replacement reaction was utilized to synthesize a new type of ternary Fe _1-xPtRu _x NCs from binary FePt NCs. The detailed structural transformation from binary FePt NCs to ternary Fe _1-xPtRu _x NCs was analyzed by X-ray absorption spectroscopy (XAS). Ternary Fe ₃₅Pt ₄₀Ru ₂₅, Fe ₃₁Pt ₄₀Ru ₂₉, and Fe ₁₇Pt ₄₀Ru ₄₃ NCs exhibit superior catalytic ability to withstand CO poisoning in methanol oxidation reaction (MOR) than do binary NCs (FePt and J-M PtRu). Also, the Fe ₃₁Pt ₄₀Ru ₂₉ NCs had the highest alloying extent and the lowest onset potential among the ternary NCs. Furthermore, the origin for the superior CO resistance of ternary Fe _1-xPtRu _x NCs was investigated by determining the adsorption energy of CO on the NCs surfaces and the charge transfer from Fe/Ru to Pt using a simulation based on density functional theory. The simulation results suggested that by introducing a new metal into binary PtRu/PtFe NCs, the anti-CO poisoning ability of ternary Fe _1-xPtRu _x NCs was greatly enhanced because the bonding of CO-Pt on the NCs surface was weakened. Overall, our experimental and simulation results have indicated a simple route for the discovery of new metal alloyed catalysts with superior anti-CO poisoning ability and low usage of Pt and Ru for fuel cell applications.