Flash-Thermal Shock Synthesis of High-Entropy Alloys Toward High-Performance Water Splitting.
basic_science · Level V
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- Record sourced from PubMed, PMID 37607534.
- Also identified by DOI 10.1002/adma.202305222.
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Abstract
High-entropy alloys (HEAs) provide unprecedented physicochemical properties over unary nanoparticles (NPs). According to the conventional alloying guideline (Hume-Rothery rule), however, only size-and-structure similar elements can be mixed, limiting the possible combinations of alloying elements. Recently, it has been reported that based on carbon thermal shocks (CTS) in a vacuum atmosphere at high temperature, ultrafast heating/cooling rates and high-entropy environment play a critical role in the synthesis of HEAs, ruling out the possibility of phase separation. Since the CTS requires conducting supports, the Joule-heating efficiencies rely on the carbon qualities, featuring difficulties in uniform heating along the large area. This work proposes a photo-thermal approach as an alternative and innovative synthetic method that is compatible with ambient air, large-area, remote process, and free of materials selection. Single flash irradiation on carbon nanofibers induced momentary high-temperature annealing (>1800 °C within 20 ms duration, and ramping/cooling rates >10<sup>4</sup> K s<sup>-1</sup> ) to successfully decorate HEA NPs up to nine elements with excellent compatibility for large-scale synthesis (6.0 × 6.0 cm<sup>2</sup> of carbon nanofiber paper). To demonstrate their feasibility toward applications, senary HEA NPs (PtIrFeNiCoCe) are designed and screened, showing high activity (η<sub>overall</sub> = 777 mV) and excellent stability (>5000 cycles) at the water splitting, including hydrogen evolution reactions and oxygen evolution reactions.