Balancing Hydrogen and Hydroxyl Binding Energies Drives pH-Universal Hydrogen Evolution in High-Entropy Alloys

The development of efficient, pH-universal hydrogen evolution reaction (HER) electrocatalysts is crucial for advancing sustainable hydrogen production technologies compatible with diverse electrolyte environments. High-entropy alloys (HEAs) have emerged as promising platforms, yet rational design beyond elemental randomization is highly required. In this work, guided by hydrogen binding energy (HBE) and hydroxyl binding energy (OHBE) descriptors, we strategically designed a CoNiRhIrPt HEA catalyst. It exhibits exceptional HER activity across the entire pH range, requiring overpotentials of only 13 mV in acid and 5 mV in alkali to achieve 10 mA cm^-2. Furthermore, its mass activity at -0.05 V surpasses that of commercial Pt/C by 6.2 and 6.3 times in acidic and alkaline media, respectively. When integrated into an anion-exchange membrane water electrolyzer (AEMWE), the catalyst enables stable hydrogen generation at 500 mA cm^-2 for over 1200 h. Structural characterization and density functional theory (DFT) calculations confirm significant lattice distortion and the synergistic electronic coupling effect in CoNiRhIrPt, which optimally tunes the intermediate adsorption. This work not only presents a strategic design of superior pH-universal HER catalysts but also decouples the mechanistic link between compositional complexity and catalytic performance in HEAs, providing a reference for the rational design of electrocatalysts.