The rational design of active, durable and low-cost catalysts for oxygen reduction reactions is highly desirable in PEMFCs. Nanoparticles with core (Pt-based alloy)/shell (few layers of Pt skin) structure as a subtly designed derivative of pure Pt, has attracted much attention due to its lower cost and comparable activity compared with Pt. By careful configuration of the core alloys, the atomic arrangement in the shell can be manipulated effectively, revealing better ORR performance than pure Pt. In this work, the structure-activity relationship is investigated by DFT simulations on the face-centered tetragonal (FCT) core with Pt shell using a slab model. The (111) surface of Pt-M (M=V, Cr, Fe, Co, Ni and Cu) with intermetallic FCT structure have been studied. Meanwhile, the effect of ordered structure with various numbers of Pt shell layers is discussed. We comprehensively explore the interaction between Pt layers and host materials to acquire the best Pt thickness associated with the certain host material, tuning the ORR activity toward the peak of the ORR volcano plot. Moreover, the ligand, strain and shear effect in FCT system are decoupled to determine the dominant role among them. At last, we have shown that synthesized the Pt-Fe intermetallic FCT phase perfectly matches our theory and serves as a robust electrocatalyst with enhanced activity and stability towards ORR. Our results could facilitate further design of ordered intermetallic FCT structure in ORR applications.<br/>

Unveiling the effect of Pt-based face-centered tetragonal core in core/shell nanoparticles for oxygen reduction reactions

255th National Meeting (2018)

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