High-entropy alloy catalysts with optimized structure, strain, and charge distribution for efficient oxygen reduction reaction

Based on an entropy-driven strategy, novel multi-component high-entropy alloy nanobranches (HEA NBs) are synthesized to solve the challenges of limited intrinsic activity and poor durability in oxygen reduction reactions (ORR). The unique HEA NBs significantly enhance facet density and generate abundant unsaturated active sites through lattice distortion effects, thereby adjusting the d-band center and changing electronic structure, effectively reducing the adsorption energy barrier, optimizing the activation energy for the four-electron pathway. Electrochemical tests reflect that HEA NBs have a half-wave potential of 0.943 V and mass activity of 1.75 (A mg −1 Pt ), which is 11.7 times higher than commercial Pt/C, and decays about 22 % after 30,000 cycles. Notably, in the proton exchange membrane fuel cell, the peak power density of 1.61 W cm −2 is achieved by HEA NBs at an ultra-low load. Geometric phase analysis reveals a compressive strain effect driven by entropy. This work establishes a composition-structure-performance relationship for high-entropy alloys, providing a new potential for designing electrocatalysts.