Ultrafast laser synthesis of sub-10 nm FeCoNiMnCr high-entropy alloy nanoparticles for enhanced oxygen evolution catalysis

• A rapid laser irradiation method enables the synthesis of sub-10 nm FeCoNiMnCr high-entropy alloy nanoparticles on carbon nanotube paper, achieving homogeneous elemental mixing and phase-pure FCC structure. • The ultrafast heating and quenching processes suppress Ostwald ripening, leading to ultrafine nanoparticles with enhanced catalytic performance. • The synthesized catalyst exhibits exceptional OER activity with a low overpotential of 255 mV at 10 mA·cm−2 and remarkable stability over 100 hours in alkaline media. • This work provides a scalable and efficient strategy for the preparation of high-entropy alloy nanoparticle catalysts, advancing cost-effective renewable energy conversion.