Mitigating the Pt Dissolution of Pt–Cr Intermetallics during the Oxygen Reduction Reaction in Acid Medium
Carlos A. Campos‐Roldàn, Rachelle Alalam, Hazar Guesmi, Jean‐Sébastien Filhol, Raphaël Chattot, Pierre‐Yves Blanchard, Jacques Rozière, Deborah J. Jones, Sara Cavalière
Abstract
Platinum-based intermetallic nanostructures are considered promising electrocatalysts for the sluggish oxygen reduction reaction (ORR). Notwithstanding, degradation issues, such as metal dissolution, still hamper the large-scale implementation of these materials. Herein, by using the Pt–Cr intermetallic system as case of study, we have produced carbon-supported nanoparticles (NPs) of ca. 5 nm whose crystalline structure was carefully tuned, obtaining the L1 2 Pt 3 Cr and the L1 0 PtCr phases. The electrochemical stability toward the ORR of both Pt–Cr intermetallics presents a clear benefit relative to the Pt/C benchmark. Our experimental results, supported by theoretical calculations, indicate an enhanced metal dissolution resistance of both Pt–Cr intermetallics, the origin of which stems from a high intrinsic kinetic barrier for oxygen adsorption-induced Cr segregation and a built-in formation of Cr–O that stabilizes the adjacent Pt sites during the cathodic dissolution. This work provides insights and strategies for the rational design of robust Pt-based ORR electrocatalysts.