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Irreversible structural dynamics on the surface of bimetallic PtNi alloy catalyst under alternating oxidizing and reducing environments.

I. Khalakhan, L. Vega, M. Vorokhta, T. Skála, F. Viñes, Y. V. Yakovlev, K. M. Neyman, I. Matolínová.
Appl. Catal. B: Environ.264 (2020) 118476

Calculated equilibrium chemical ordering in 1:1 Pt:Ni nanocrystals containing 201 and 314 atoms.

This combined experimental and computational modelling study provides new insights into the PtNi alloy surface chemistry under reactive environments. It allowed gaining advanced understanding of the action of PtNi catalysts at real conditions, including their long-time catalytic performance in fuel cells. The surface segregation of Ni species caused by reactive environments suppresses PtNi alloy on the surface which is critical for its high electrocatalytic performance. Based on the obtained results a general strategy towards adjustment of PtNi catalyst surfaces has been proposed. The redox pre-treatment of the surface of bimetallic catalysts may open an effective way to engineer highly efficient catalysts for various catalytic processes.