Simple Replacement Reaction for the Preparation of Ternary Fe_1–<i>x</i>PtRu_<i>x</i> Nanocrystals with Superior Catalytic Activity in Methanol Oxidation Reaction

Abstract

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–<i>x</i>PtRu_<i>x</i> NCs from binary FePt NCs. The detailed structural transformation from binary FePt NCs to ternary Fe_1–<i>x</i>PtRu_<i>x</i> NCs was analyzed by X-ray absorption spectroscopy (XAS). Ternary Fe₃₅Pt₄₀Ru₂₅, Fe₃₁Pt₄₀Ru₂₉, and Fe₁₇Pt₄₀Ru₄₃ 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 Fe₃₁Pt₄₀Ru₂₉ 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–<i>x</i>PtRu_<i>x</i> 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–<i>x</i>PtRu_<i>x</i> 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