PtCoFe Intermetallic Alloy Catalyst Derived from PtFe@CoO with High Stability for Oxygen Reduction Reaction

Abstract Platinum‐based ordered alloy catalysts possess higher intrinsic activity in oxygen reduction reactions (ORR). High‐temperature annealing during ordered alloy formation frequently results in larger nanoparticles, and the strategy for obtaining ordered alloys at 600 °C is still undefined. Herein, an ordered Fe‐doped PtCo catalyst (O‐PtCoFe/C) with a size of sub‐4 nm was prepared at 600 °C derived from PtFe@CoO. CoO can generate oxygen vacancies by H2 reduction, lowering the atomic migration barrier and serving as a protective layer to inhibit nanoparticle migration. Experimental analyses showed the formation of O‐PtCoFe/C and electron‐rich Pt atoms due to Pt, Co, and Fe, which was advantageous for ORR performance. The mass activity of the prepared catalyst for ORR was 382.8 mA mgPt−1, which is 5.4 times greater than Pt/C. After 10000 potential cycles, the half‐wave potential was only negatively shifted by 10 mV. In PEMFC (proton exchange membrane fuel cells) tests, the O‐PtCoFe/C showed only 3 % decay after 3000 cycles, whereas the Pt/C showed a significant loss (18.4 %). This work provides an effective method for preparing ordered PtCo alloys for fuel cell cathode catalysts at 600 °C.