Highly Durable and Active Ternary Pt–Au–Ni Electrocatalyst for Oxygen Reduction Reaction

Abstract

Long‐term stable and high active catalysts for oxygen reduction reaction (ORR) are required for the commercialization of proton exchange membrane fuel cells (PEMFCs). Platinum (Pt) catalyst is the preferred choose for ORR, but the stability and activity of existing Pt catalyst are unsatisfactory for the commercialization of PEMFCs. Here the ternary Pt–Au–Ni/C and binary Pt–Ni/C are synthesized by a rapid microwave‐assisted polyol reduction. The Pt–Au–Ni/C exhibits superior ORR activity to both of Pt–Ni/C and commercial Pt/C. Moreover, the Pt–Au–Ni/C exhibited the long‐term stability in both of half‐cell and single‐cell accelerated degradation tests. The above results indicate that the addition of Au into binary Pt–Ni catalyst can not only enhance the stability but also improve the electrocatalytic activity.

Structure Design Reveals the Role of Au for ORR Catalytic Performance Optimization in PtCo‐Based Catalysts

“…[ 32 ] On the other hand, the introduction of Au was expected to elevate the d‐band center of Pt owing to the tensile effect since Au has relative larger radius. [ 22 ] Ligand effect could also contribute to the lowered d‐band center via electron interaction among Pt, Au and Co. [ 23 ] In our case, the d‐band center in both the core–shell and sandwich structures was higher than that in Pt 4 Co, which was another evidence for the Au outward segregation. Moreover, it can be seen that the introduction of Co interlayer made the Pt4f 7/2 core level of Au@Co@PtCoAu positively shifted ≈0.04 eV relative to Au@PtCoAu owing to the compressive strain from the Co dominating interlayer.…”

“…On the basis of the above discussion, it could be concluded undoubtedly that Au was preferred to segregate toward and over the Pt‐based surface, which had been predicted by several theoretical calculations. [ 21–23 ] However, previous reports gave no direct experimental evidence.…”

“…“Healing” effect as proposed by Adzic et al in their work on PdAu@Pt core–shell structure might explicate the prevented Co loss by Au introduction. [ 21–23 ] In their opinion, the outward‐diffused Au atoms might segregate preferentially at the defect sites of the multimetallic shell layer, which was energetically favorable for Co dissolution. By mending such defects, the Co and Pt dissolution could be suppressed to some extent.…”

“…[ 20 ] According to the theoretical calculation, it was energetically favorable for Au to segregate towards and over Pt surface to mend the defective sites, which might inhibit the composition degradation and thus boost the catalytic durability. [ 21–23 ] Although the experimental results seemed to confirm the theoretical prediction, there is still lack of the direct evidence to illustrate the detailed composition distribution for the Au@Pt‐based core–shell structures and thus impeded the deep understanding on the key factors determining the catalytic performance, which is of fundamental importance for the optimized design of catalysts with simultaneous high activity and superior durability. In this work, we addressed this issue by taking Au‐core@PtCo‐shell structure as a model system to reveal how Au contributed to the improved ORR catalytic performance of Pt‐based nanocatalyst.…”

Unique Half Embedded/Exposed PdFeCu/C Interfacial Nanoalloy as High‐Performance Electrocatalyst for Oxygen Reduction Reaction

“…Thus, the engineering of highly stable and efficient strategy for the realization of active fuel cell EC is still desirable. In particular, fuel cell ECs for cathodic oxygen reduction reaction (ORR) need to be very effective for overall performance of fuel cells –. This is because of the slow kinetics associated with the ORR process which limits active fuel cell materialization.…”