Size‐Controllable High‐Entropy Alloys Toward Stable Hydrogen Production at Industrial‐Scale Current Densities

Abstract Efficient and stable electrocatalytic hydrogen evolution reaction (HER) at high current densities is highly desirable for industrial‐scale hydrogen production, which is yet challenging, because of the electrocatalyst with short lifespans during the acidic HER process. Here, a controllable preparation technique is successfully developed to synthesize PdPtRuRhAu high‐entropy alloys (HEAs) of various sizes, within the 3.14 nm particles (HEA‐3.14) demonstrating exceptional catalytic performance and stable hydrogen production at current densities of −500 and −1000 mA·cm −2 with negligible activity loss over 100 h. Theoretical calculations indicate that the bridge adsorption site of Pd–Au serves as an ideal location for HER, with HEA‐3.14 possessing the highest proportion of such sites, reaching 18.97%. To further analyze the thermodynamic stability of HEAs, an element‐encoding machine learning model is developed from over 300 000 preprocessed dataset of HEAs that achieving an impressively low RMSE of 58.6 °C and a high R 2 value of 0.98. By integrating thermodynamic modeling with machine learning methods, the melting point of the PdPtRuRhAu HEAs at 3.14 nm (366 °C) is predicted, which aligns well with the results obtained from differential scanning calorimetry tests. This work offers new insights and approaches for designing HEAs that reliably produce hydrogen at high current densities.