Laser-thermal reduction synthesis of high-entropy alloys towards high-performance pH universal hydrogen evolution reaction

Owing to their multi-elemental compositions and unique high-entropy mixing states, high-entropy alloy (HEA) nanoparticles (NPs) displaying tunable activities and enhanced stabilities thus have become a rapidly growing area of research in recent years. However, the integration of multiple elements into HEA NPs at the nanoscale remains a formidable challenge, especially when it comes to the precise control of particle size, elemental composition and content. Herein, a simple and universal high-energy laser assisted reduction approach is presented, which achieves the preparation of HEA NPs with a wide range of multi-component, controllable particle sizes and constitution on different substrates within seconds. Laser on carbon nanofibers induced momentary high-temperature annealing (>2000 ​K and ramping/cooling rates > 10⁵ ​K ​s⁻¹) to successfully decorate HEA NPs up to twenty elements with excellent compatibility for large-scale synthesis (20.0 ​× ​20.0 ​cm² of carbon cloth). The IrPdPtRhRu exhibit robust electrocatalytic hydrogen evolution reaction (HER) activities and low overpotentials of 16, 28, and 12 ​mV at a current density of 10 ​mA ​cm⁻² in alkaline (1.0 ​M KOH), alkaline simulated seawater (1.0 ​M KOH ​+ ​0.5 ​M NaCl), and acidic (0.5 ​M ​H₂SO₄) electrolytes, respectively, and excellent stability (7 days and >2000 cycles) at the alkaline HER.