High-entropy alloys (HEAs) have recently emerged as promising electrocatalysts for complex reactions owing to their tunable electronic structures and diverse, unique binding sites. However, their vast compositional space, in terms of both elemental variety and atomic ratios, presents a major challenge to the rational design of high-performance catalysts, as experimental efforts are often hindered by ambiguous element selection and inefficient trial-and-error methods. In this work, a bottom-up research strategy using machine learning-assisted first-principles calculations was applied to accelerate the design of quinary HEAs toward efficient multielectron transfer reactions. Here, we report the design of PtPdRhRuMo, which exhibits key physicochemical properties favoring the methanol oxidation reaction. Notably, the incorporation of Mo as the fifth element significantly activates specific binding sites on HEA surfaces, enhancing methanol adsorption and, in particular, the water dissociation ability. This facilitates hydroxyl species formation, which effectively mitigates CO intermediate adherence while promoting the complete oxidation of CH3OH to CO2 via alternative reaction pathways. Guided by theoretical predictions, experimental samples with different morphologies of mesoporous PtPdRhRuMo catalyst (m-HEANP(Mo) nanoparticles and m-HEAF(Mo) thin film) were then synthesized, demonstrating superior electrocatalysis with a large current density of up to 18.20 mA cm-2 and a mass activity of 9.89 A mgPt-1, alongside the long-term durability for efficient methanol electrooxidation applications.
Nam et al. (2025) studied this question.