In this paper,we report the design of ultrafine ordered PtFeZn ternary intermetallics uniformly supported on ZIF-8-derived Zn,N-codoped graphitic carbon(ZnNC)via a green aqueous impregnation method followed by a two-s...In this paper,we report the design of ultrafine ordered PtFeZn ternary intermetallics uniformly supported on ZIF-8-derived Zn,N-codoped graphitic carbon(ZnNC)via a green aqueous impregnation method followed by a two-step annealing protocol(H_(2)/Ar,600 and 800℃)to circumvent the sintering issues imposed by conventional thermodynamics.Physical characterizations(X-ray diffraction,high-angle annular dark-field scanning transmission electron microscopy,X-ray absorption spectroscopy)and theoretical calculations reveal that low-temperature annealing at 600℃stabilizes sub-nano disordered PtFe alloys via the strong metal-support interactions(SMSI)between Zn in ZnNC and Pt precursors,while high-temperature treatment at 800℃promotes Zn diffusion from the support into the alloy bulk and simultaneously triggers the disorder-to-order phase transition.The as-prepared ZnNC-15PtFeZn exhibits an initial mass activity of 0.769 mA/μgPt and retains 61.7%of its activity after 30000 cycles of accelerated stress testing(AST).Notably,when used as a cathode catalyst in MEA,ZnNC-15PtFeZn achieves superior power density(2.018 W/cm^(2)under H_(2)-O_(2))at half the Pt loading(0.05 mg/cm^(2))of state-of-the-art commercial Pt/C,highlighting its potential for low-Pt PEMFCs.Density functional theory confirms that Fe enhances ORR activity via ligand effects,while Zn strengthens Pt-Fe/Zn bonding(elevating vacancy formation energies),thereby improving structural stability.This mild,scalable aqueous impregnation strategy offers a general approach for synthesizing multi-component ordered alloys in electrocatalysis.展开更多
文摘In this paper,we report the design of ultrafine ordered PtFeZn ternary intermetallics uniformly supported on ZIF-8-derived Zn,N-codoped graphitic carbon(ZnNC)via a green aqueous impregnation method followed by a two-step annealing protocol(H_(2)/Ar,600 and 800℃)to circumvent the sintering issues imposed by conventional thermodynamics.Physical characterizations(X-ray diffraction,high-angle annular dark-field scanning transmission electron microscopy,X-ray absorption spectroscopy)and theoretical calculations reveal that low-temperature annealing at 600℃stabilizes sub-nano disordered PtFe alloys via the strong metal-support interactions(SMSI)between Zn in ZnNC and Pt precursors,while high-temperature treatment at 800℃promotes Zn diffusion from the support into the alloy bulk and simultaneously triggers the disorder-to-order phase transition.The as-prepared ZnNC-15PtFeZn exhibits an initial mass activity of 0.769 mA/μgPt and retains 61.7%of its activity after 30000 cycles of accelerated stress testing(AST).Notably,when used as a cathode catalyst in MEA,ZnNC-15PtFeZn achieves superior power density(2.018 W/cm^(2)under H_(2)-O_(2))at half the Pt loading(0.05 mg/cm^(2))of state-of-the-art commercial Pt/C,highlighting its potential for low-Pt PEMFCs.Density functional theory confirms that Fe enhances ORR activity via ligand effects,while Zn strengthens Pt-Fe/Zn bonding(elevating vacancy formation energies),thereby improving structural stability.This mild,scalable aqueous impregnation strategy offers a general approach for synthesizing multi-component ordered alloys in electrocatalysis.
