Highly performing and stable ordered intermetallic L10-PtCo0.8Ti0.2 alloys for oxygen reduction reaction

Tertiary platinum-based alloy electrocatalysts on the cathode side of a proton exchange membrane fuel cells (PEMFCs) can help accelerate the sluggish oxygen reduction reaction (ORR), and there is great potential in this area. However, it is still a rather difficult problem to synthesize such a small-sized, structurally ordered ternary alloy catalysts, and no particularly good solution has been found yet. Herein, we report a ternary ordered intermetallic L1 0 -PtCo 0.8 Ti 0.2 nanocatalyst that serves as a highly active and exceptionally stable candidate. During half - cell evaluations, the refined L1 0 -PtCo 0.8 Ti 0.2 catalyst showcases outstanding catalytic capabilities, attaining a half - wave potential (E 1/2 ) of 0.939 V. Significantly, its mass activity (MA) is 9.8 times greater and specific activity (SA) is 7.9 times higher compared to those of the commercially available Pt/C catalyst. Furthermore, in single-cell PEMFC tests, the L1 0 -PtCo 0.8 Ti 0.2 cathode exhibits outstanding ORR performance, delivering an excellent MA of 0.995 A/mg Pt at 0.9 V -iR-free- alongside superior durability. DFT calculations demonstrate that the incorporation of Ti optimizes the balance between intermediate adsorption and desorption by strengthening the interaction with oxygenated intermediates, thereby significantly enhancing the ORR activity. This work provides new information for the rational design of high-performance ORR nanocatalysts.