Decipheringthe Effect of Fe and Cu in Pd Latticefor the Oxygen Reduction Reaction

Developing efficient and durable nonplatinum (Pt)-based electrocatalysts for the oxygen reduction reaction (ORR) is highly desirable and challenging. Herein, PdFeCu nanoparticles (NPs) with uniform dispersion on the carbon matrix were developed and their activity toward the ORR was explored. The study found that the introduction of copper (Cu) and iron (Fe) into the palladium (Pd) lattice effectively tunes the electronic structure of the nanomaterial. Additionally, the uniform dispersion of these NPs on the carbon surface results in a strong metallic support interaction (SMSI). This SMSI prevents agglomeration of the PdFeCu NPs, providing more active sites and enhancing the intrinsic activity of the PdFeCu/C electrocatalysts. As a result, it demonstrates several promising characteristics such as early onset (<i>E</i>_onset = 0.965 V <i>vs</i>.RHE), larger ECSA (91.9 m² g^–1) and low Tafel slope (52.5 mV dec^–1) value than the other reported electrocatalysts and comparable to Pt/C. Chronoamperometry (CA) and accelerated durability tests (ADT) demonstrate that PdFeCu/C exhibits excellent durability and stability in alkaline media. Furthermore, PdFeCu/C displays excellent MeOH tolerance, which is higher than that of the commercial Pt/C. These findings suggest that PdFeCu/C could be a promising cathode candidate for the ORR and direct methanol fuel cells (DMFCs), offering a viable alternative to Pt-based electrocatalysts.