Regulating Ordered Structure and MOR Catalytic Performance of L1 0 -FePt Nanoparticles through Mn Doping and Magnetic-Field Assistance

Abstract

This work reports the direct synthesis of L10 ordered FePtMn nanoparticles (NPs) via a synergistic approach combining Mn doping and magnetic field-assisted wet chemistry.Mn doping effectively refines the particle size, enhances high-temperature stability, and improves dispersion. The high magnetic susceptibility of Mn enhances the sensitivity of the nanoparticles to the external field, resulting in a significant increase in the ordering degree S when a 2 T magnetic field is applied. Density functional theory (DFT) calculations reveal that the d-band center ε d of Pt shifts continuously upward towards the Fermi level with increasing ordering degree and Mn content. This electronic modulation facilitates methanol activation, while the active Mn sites synergistically accelerate the oxidative removal of CO intermediates through a bifunctional mechanism. Consequently, the L10 -FePtMn (2 T) catalyst exhibits a superior mass activity of 1482 mA/mg Pt for the methanol oxidation reaction (MOR), which is 3.62 and 4.68 times that of fcc-FePt (0 T) and commercial Pt/C, respectively. This study provides a comprehensive experimental and theoretical framework for the design of high-performance Pt-based catalysts via magnetic field-assisted strategies.