A short-range ordered PtCu catalyst showing high stability in oxygen reduction reaction
The durability of platinum-group metal catalysts for oxygen reduction reaction (ORR) remains a critical determinant for the commercial viability of proton exchange membrane fuel cells (PEMFCs). Herein, we report a PtCu catalyst featured with a short-range ordered crystal structure and stabilized by a nitrogen-doped carbon shell. Notably, triphenylphosphine was strategically employed as a coordinating agent to regulate the uniformly growth of Pt and Cu complex. The N-doped carbon shell derived from zeolitic imidazolate framework-8 ( ZIF-8) served a dual protective function: (1) physically isolating PtCu nanoparticles to mitigate agglomeration during thermal annealing, and (2) electrochemically stabilizing the catalyst against dissolution under accelerated durability test. X-ray absorption fine structure (XAFS), supported by density functional theory (DFT) calculations revealed that the short-range ordered structure in the PtCu kinetically impeded both Pt leaching and Cu segregation, which is beneficial for improving catalyst stability. Durability tests demonstrates only 15 % mass activity loss after 50 K electrochemical cycles, underscoring the efficacy of Pt-Cu interface design in addressing durability challenges for PEMFC cathodes.
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