Medium-Entropy Engineering of Pt/FeCo Layered Double Hydroxide for Synergistically Enhanced Alkaline Hydrogen Evolution

Developing efficient, stable, low-platinum (Pt)-loading electrocatalysts for the hydrogen evolution reaction (HER) is key for advancements in green hydrogen technology. In this work, a “medium-entropy engineering” strategy was introduced simply by a two-step hydrothermal method. Then a low-loading Pt/FeCo layered double hydroxide (LDH) medium-entropy hybrid (MEH) electrocatalyst was constructed on nickel foam. Systematic characterization shows that this approach affords the dispersion of Pt nanoparticles onto a three-dimensional flower-like nanostructure and plentiful surface defects. X-ray photoelectron spectroscopy (XPS) analysis shows strong electron interaction between Pt and the FeCo LDH support and cooperatively tunes the electronic structure as a consequence. In 1 M KOH electrolyte, Pt/FeCo LDH-MEH-0.02 exhibits excellent HER activity with overpotentials of only 19 mV and 64 mV to deliver current densities of 10 mA cm –2 and 100 mA cm –2 respectively to outperform commercial Pt/C and a series of control samples. Furthermore, its Tafel slope is low at 30.1 mV dec –1, has a significantly lowered charge-transfer resistance and long-term excellent operation stability. Our study reports a design strategy for preparing high-performance, low-Pt-loading electrocatalysts through medium-entropy engineering.