Ordered Pt3Co Catalysts Derived from ZIF-67 Templated Carbon for Oxygen Reduction Reaction

Thermal annealing at high temperatures is usually employed to alloy Pt with transitional metals to produce structurally ordered intermetallic electrocatalysts for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. The most important issue to address in this approach is the particle aggregation during thermal annealing. Herein, the repetitive absorption/chemical reaction method is used to prepare zeolitic-imidazolate-framework-coated carbon and alloy particles by simply soaking an ordered Pt3Co (O-Pt3Co) sequentially in Co(NO3)2 and 2-methylimidazole solutions at room temperature. The as-prepared catalysts display impressive ORR activity and stability relative to their commercial Pt/C counterpart. The optimized catalyst demonstrates a mass and specific activities of 0.53 A mgPt−1 and 0.91 mA cm−2, respectively. In addition, no obvious decay is observed after 30 000 voltammetric cycles from 0.6 V to 0.9 V. The mechanism study shows that Co and doped N play a key role in promoting ORR activity and stability.