Design and Synthesis of PtPdNiCoMn High‐Entropy Alloy Electrocatalyst for Enhanced Alkaline Hydrogen Evolution Reaction: A Theoretically Supported Predictive Design Approach

Abstract Electrocatalytic hydrogen generation requires a cutting‐edge, multifunctional electrocatalyst with abundant active sites to drive multielectron transfer reactions. High entropy alloys (HEA) are complex five or more‐element alloy systems with high configurational entropy which makes them unique materials for next‐generation electrocatalysts. Here, in this work, based on new screening guidelines for catalyst selections that combine density‐functional theory calculated Gibbs formation‐enthalpy with bond length and electronegativity variance, a novel HEA electrocatalyst consisting of five elements, namely, Pt, Pd, Ni, Co, and Mn is designed. By simple room temperature electrodeposition, the designed catalyst is prepared and its hydrogen evolution reaction (HER) is explored and validated through experimental and theoretical approaches. The HEA demonstrated a superior HER activity with an overpotential of 22.6 mV at −10 mA cm −2 which outperforms Pt/C commercial catalyst. No evident degradation of the material is detected even after 100 hours of continuous operation under high current density. Moreover, the HEA has shown exceptional performance in harsh electrolyte conditions such as in simulated seawater and actual seawater. Remarkably, the density‐functional theory calculated small Gibbs formation‐enthalpy (≈0 eV) compared to Pt/C places the new HEA near the apex of Trasatti's model of Volcano plot, which is also suggestive of superior HER activity.