Optimized Surface Strain in L10-Type Pt0.8Ga0.2Co Intermetallic Catalyst for Enhanced Oxygen Reduction in Fuel Cells

Abstract

Tuning surface strain has been proven to be an efficient strategy for improving the kinetics of the oxygen reduction reaction of Pt–M electrocatalysts (M = non-noble metals). However, it remains a grand challenge to achieve optimal compressive strain, particularly on a platform of low-Pt nanocrystals. Herein, we report a novel approach involving the partial substitution of a Pt site with Ga, resulting in the development of a high-performance L1₀-type Pt_0.8Ga_0.2Co intermetallic catalyst. The incorporation of Ga not only fine-tunes the surface strain to approach the optimum region of the theoretical volcano plot but also facilitates the formation of a more stable intermetallic structure dynamically. This enhancement significantly improves long-term electrochemical durability. Pt_0.8Ga_0.2Co/C exhibits a markedly improved intrinsic activity of 3.39 mA cm^–2 and, more importantly, a high mass activity of 0.77 A mg_Pt^–1 at 0.90 V in a fuel cell, surpassing the performance of most previously reported L1₀ Pt-based intermetallics. Notably, catalytic durability is confirmed through only 28% mass activity loss after 30,000 potential cycles (vs 40% loss for the DOE target). This work paves the way for the development of promising low-Pt electrocatalysts for efficient energy conversion devices.