Controllable moderate-temperature synthesis of high entropy PtIrCoNixFe1-x for superior hydrogen evolution reaction

Platinum (Pt) is renowned for its remarkable catalytic activity in the hydrogen evolution reaction (HER); however, its significant cost constrains its widespread use. Integrating Pt with transition metals optimizes its electronic structure, enhancing catalytic efficiency while reducing Pt reliance. This study reports the synthesis of PtIrCoNi x Fe 1-x high-entropy alloy nanoparticles (HEA NPs) via a moderate-temperature solvothermal method, offering a cost-efficient solution for achieving high HER activity with reduced Pt content. Structural analyses (PXRD, XPS , TEM, EDX mapping) confirm the formation of single-phase HEAs with evenly distributed elements. By adjusting Ni and Fe ratios, PtIrCoNi 2 · 9 Fe 3.9 HEA NPs sample show superior HER activity, outperforming commercial Pt/C with a low overpotential of 27 mV at −10 mA cm −2 and a Tafel slope of 37.8 mV dec −1 in alkaline media. DFT simulations reveal that the enhanced HER activity of the HEAs is due to d-d electron interactions and multiple active sites that lower energy barriers. Ir-5d orbitals facilitate electron transfer , while Pt-5d orbitals act as an electron reservoir. Ni-3d, Fe-3d, and Co-3d orbitals near the Fermi level create an electron depletion center, further improving HER activity. These findings highlight the potential of PtIrCoNi x Fe 1-x HEA NPs as tunable HER electrocatalysts . This study introduces a refined solvothermal method for synthesizing PtIrCoFe x Ni 1-x high-entropy alloy (HEA) nanoparticles with controlled composition and enhanced phase stability. By optimizing Ni and Fe concentrations, the catalysts achieve outstanding HER performance with low overpotential and high durability in alkaline conditions. This scalable approach offers a cost-effective pathway for large-scale hydrogen production, supporting global clean energy and decarbonization goals. • PtIrCoNi x Fe 1-x HEAs were synthesized via a moderate-temperature solvothermal method. • Optimizing the HER performance by varying Ni and Fe concentrations. • PtIrCoNi 2 · 9 Fe 3.9 HEA showed 27 mV overpotential at −10 mA cm −2 . • DFT studies confirm that d-d coupling and multiple active sites lower energy barriers.