PtFeCoNiMo high-entropy alloy nanocatalysts for high-performance alkaline hydrogen evolution

Abstract

To address the bottlenecks of high cost and insufficient stability of commercial Pt-based catalysts for the alkaline hydrogen evolution reaction (HER), a novel Pt₂₇Fe₃₀Co₂₇Ni₉Mo₇/C high-entropy alloy nanocatalyst was synthesized via a facile one-step solvothermal method. Material characterization studies (via XRD, TEM, XPS, and ICP-OES) confirmed that the catalyst has a homogeneous face-centered cubic (FCC) structure, with ∼14.65 nm nanoparticles and uniform atomic-scale dispersion of Pt, Fe, Co, Ni, and Mo. All metals exist in mixed metallic/oxidized states, favoring electron transfer and intermediate adsorption. Electrochemical tests in 1 M KOH showed exceptional HER performance: 24 mV overpotential at 10 mA cm⁻², 48.44 mV dec⁻¹ Tafel slope, and 2.388 s⁻¹ turnover frequency (TOF) at 50 mV overpotential, outperforming quaternary Pt₂₇Fe₂₉Co₃₃Ni₁₁/C and commercial Pt/C. It retained activity/structure after 5000 CV cycles and 40 000 s chronopotentiometry. Mechanistically, the synergistic effect of balanced Pt/Fe/Co/Ni/Mo elemental ratios and Mo-induced d-band center shift optimizes *H/*OH adsorption—weakening excessive *H adsorption while promoting *OH adsorption—thus enhancing alkaline HER kinetics. This work offers a strategy for high-performance Pt-based catalysts, with great industrial application potential in alkaline water electrolysis.