Optimized\nSurface Strain in L1<sub>0</sub>‑Type\nPt<sub>0.8</sub>Ga<sub>0.2</sub>Co Intermetallic Catalyst for Enhanced\nOxygen Reduction in Fuel Cells

Tuning surface strain has been proven to be an efficient\nstrategy\nfor improving the kinetics of the oxygen reduction reaction of Pt–M\nelectrocatalysts (M = non-noble metals). However, it remains a grand\nchallenge to achieve optimal compressive strain, particularly on a\nplatform of low-Pt nanocrystals. Herein, we report a novel approach\ninvolving the partial substitution of a Pt site with Ga, resulting\nin the development of a high-performance L1<sub>0</sub>-type Pt<sub>0.8</sub>Ga<sub>0.2</sub>Co intermetallic catalyst. The incorporation\nof Ga not only fine-tunes the surface strain to approach the optimum\nregion of the theoretical volcano plot but also facilitates the formation\nof a more stable intermetallic structure dynamically. This enhancement\nsignificantly improves long-term electrochemical durability. Pt<sub>0.8</sub>Ga<sub>0.2</sub>Co/C exhibits a markedly improved intrinsic\nactivity of 3.39 mA cm<sup>–2</sup> and, more importantly,\na high mass activity of 0.77 A mg<sub>Pt</sub><sup>–1</sup> at 0.90 V in a fuel cell, surpassing the performance of most previously\nreported L1<sub>0</sub> Pt-based intermetallics. Notably, catalytic\ndurability is confirmed through only 28% mass activity loss after\n30,000 potential cycles (vs 40% loss for the DOE target). This work\npaves the way for the development of promising low-Pt electrocatalysts\nfor efficient energy conversion devices.