MOF-Derived\nBimetallic Pd–Co Alkaline ORR Electrocatalysts

Abstract

The\ndevelopment of highly active, durable, and low-cost electrocatalysts\nfor the oxygen reduction reaction (ORR) has been of paramount importance\nfor advancing and commercializing fuel cell technologies. Here, we\nreport on a novel family of Pd–Co binary alloys (Pd<i>_x</i>Co, <i>x</i> = 1–6) embedded\nin bimetallic organic framework (BMOF)-derived polyhedral carbon supports.\nBMOF-derived Pd₃Co, annealed at 300–400 °C,\nexhibited the most promising ORR activity among the family of materials\nstudied, with a half-wave potential (<i>E</i>_1/2) of 0.977 V vs RHE and a mass activity of 0.86 mA/μg_Pd in 1 M KOH, both values being superior to those of commercial Pd/C\nelectrocatalysts. Moreover, it maintained robust durability after\n20,000 potential cycles with a minimal degradation in <i>E</i>_1/2 of 10 mV. The enhanced performance and stability are\nascribed to the uniform elemental distribution of Pd and Co and the\nCo-containing N-doped carbon (Co–N–C) structures. In\nanion exchange membrane fuel cell (AEMFC) tests, the peak power density\nof the cell employing a BMOF-derived Pd₃Co cathode reached\n1.1 W/cm² at an ultralow Pd loading of 0.04 mg_Pd/cm². Strategies developed herein provide promising insights\ninto the rational design and synthesis of highly active and durable\nORR electrocatalysts for alkaline fuel cells.