Simulations on Bimetallic Alloy Surfaces

Bimetallic alloys have modified electronic structures on the surface, and so adsorption energy changes of certain intermediates may enhance the overall catalytic activity. Zhang et al. have performed periodic DFT calculations on a Pt monolayer on Au(lll), Rh(lll), Pd(lll), Ir(lll), and Ru(OOOl) substrates. Zhang and coworkers have also undertaken simulations on mixed Pt-M (80 20) monolayers (M = Ir, Ru, Rh, Pd, Au, Re, or Os) 

Norskov et al. also contributed to different ex situ and in situ experiments with DFT to investigate the catalytic activity of (111) 

So far, various studies focused on developing catalyst materials with improved ORR activity, but only few reported the stability and durability of ORR catalysts. The study of accelerated durability tests (ADT) in conjunction with electron microprobe analysis (BMPA), LEED, and XRD techniques on Pt-based al-loys ° observed hd metal dissolution, diffusion of 3 i metals into the membrane, formation of bulk oxides on the surface, and migration and agglomeration of Pt. Yu et al. compared the durability and activity of PtCo/C with Pt/C catalysts. Throngh determination of the electrochemically active sniiace area, mass, and specific activities with respeet to the potential cycles, they found the overall cell performance of PtCo/C is higher than that of Pt/C. They also concluded that the observed dissolution of Co has no severe impact on the cell performanee or membrane conductance. Additionally, Popov et al studied the stabihty of Pt M/C for X = 1,3 and M = V, Fe, Ni, Co. ADT analyses revealed that Pt/C has the lowest activity when eompared to Pt-alloy catalysts, and that the metal dissolntion is lower for a Pt M ratio of 3 1 than compared to a 1 1 ratio. Also, Pt-Ni showed a lower dissolution rate than the other considered Pt-M alloys. 

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