Molecular dynamics simulations of ternary PtxPdyAuz fuel cell nanocatalyst growth. (21st December 2016)

• Record Type: Journal Article
• Authors: Brault, P.; Coutanceau, C.; Jennings, P.C.; Vegge, T.; Berndt, J.; Caillard, A.; Baranton, S.; Lankiang, S.
• Is Part Of: International journal of hydrogen energy. Volume 41:Number 47(2016)
• Page Start: 22589
• Page End: 22597
• Publication Date: 2016-12-21
• Subjects: Molecular dynamics simulations -- Ternary nanocatalyst -- PEMFC -- Fuel cell electrode -- Core–shell -- Alloy; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2016.08.035
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Molecular dynamics simulation of PEMFC cathodes based on ternary Pt70 Pd15 Au15 and Pt50 Pd25 Au25 nanocatalysts dispersed on carbon indicate systematic Au segregation from the particle bulk to the surface, leading to an Au layer coating the cluster surface and to the spontaneous formation of a Pt@Pd@Au core–shell structure. For Au content below 25 at%, surface Ptx Pdy active sites are available for efficient oxygen reduction reaction, in agreement with DFT calculations and experimental data. Simulations of direct core@shell system prepared in conditions mimicking those of plasma sputtering deposition pointed out an increase of the number of accessible Ptx Pdy surface active sites. Core-shell nanocatalyst morphology changes occur due to impinging Pt kinetic energy confinement and dissipation. Highlights: MD simulations shows Au surface segregation during ternary nanocatalyst growth. Au segregation observed in MD simulations is consistent with DFT calculations and ORR. Ternary alloyed Ptx Pdy Auz nanocatalyst are well crystallized at room temperature. Core@shell Pd25 Au25 @Pt50 show various morphology transformation during growth. Transferred kinetic energy of Pt atoms forming the shell is confined in the core.