MOF-Derived Bimetallic Pd-Co Alkaline ORR Electrocatalysts

The development of highly active, durable, and low-cost electrocatalysts for the oxygen reduction reaction (ORR) has been of paramount importance for advancing and commercializing fuel cell technologies. Here, we report on a novel family of Pd- Co binary alloys (PdxCo, x = 1-6) embedded in bimetallic organic framework (BMOF)-derived polyhedral carbon supports. BMOF-derived Pd3Co, annealed at 300-400 degrees C, exhibited the most promising ORR activity among the family of materials studied, with a half-wave potential (E1/2) of 0.977 V vs RHE and a mass activity of 0.86 mA/mu gPd in 1 M KOH, both values being superior to those of commercial Pd/C electrocatalysts. Moreover, it maintained robust durability after 20,000 potential cycles with a minimal degradation in E1/2 of 10 mV. The enhanced performance and stability are ascribed to the uniform elemental distribution of Pd and Co and the Co-containing N-doped carbon (Co-N-C) structures. In anion exchange membrane fuel cell (AEMFC) tests, the peak power density of the cell employing a BMOF-derived Pd3Co cathode reached 1.1 W/cm2 at an ultralow Pd loading of 0.04 mgPd/ cm2. Strategies developed herein provide promising insights into the rational design and synthesis of highly active and durable ORR electrocatalysts for alkaline fuel cells.

Automated summary

Developing highly active, durable, and low-cost electrocatalysts for the oxygen reduction reaction (ORR) is crucial for advancing and commercializing fuel cell technologies. This study reports a novel family of Pd-Co binary alloys embedded in bimetallic organic framework-derived polyhedral carbon supports. Among the materials studied, annealed BMOF-derived Pd3Co exhibits the most promising ORR activity and stability. The strategies developed in this research provide promising insights into the rational design and synthesis of ORR electrocatalysts for alkaline fuel cells.