Enhanced ORR Activity via Synergistic Effects between AgGa and CuGa Intermetallics in a Gallium Matrix

Developing cost-effective electrocatalysts to overcome the sluggish kinetics of the oxygen reduction reaction (ORR) is essential for advancing fuel cells and metal–air batteries. In this work, we report a low-temperature synthesis approach that utilizes a Ga-based liquid metal to form well-defined Ag and Cu intermetallic compounds embedded within a gallium (Ga) matrix. The resulting intermetallics undergo partial surface restructuring upon acid pretreatment, which significantly enhances their ORR activity. Notably, the ternary system comprising 1 wt % Cu, 1 wt % Ag, and 98 wt % Ga exhibits a high limiting current density of 1.85 mA/cm2 and an early onset potential of 0.7 V (at −0.1 mA/cm2). Density functional theory (DFT) calculations reveal complementary catalytic roles among the three components, CuGa2 intermetallic, Ag6.48Ga2.52 intermetallic, and CuAg alloy. This work establishes a versatile platform for tuning multimetallic compositions in liquid metal matrices, offering a promising strategy for designing high-performance, cost-effective electrocatalysts beyond noble metals.