Molten salt synthesis of high-entropy alloy AlCoCrFeNiV nanoparticles for the catalytic hydrogenation of p-nitrophenol by NaBH4

High-entropy alloy (HEA) AlCoCrFeNiV nanoparticles were prepared from oxide precursors using a molten salt synthesis method without an electrical supply. The oxide precursor was directly reduced by CaH2 reducing agent in molten LiCl at 600 degrees C-700 degrees C or molten LiCl-CaCl2 at 500 degrees C-550 degrees C. When the reduction was conducted at 700 degrees C, a face-centered cubic (FCC) structure produced, as identified by X-ray diffraction analysis. With lower reduction temperatures, the FCC structure was absent, replaced by a body-centered cubic (BCC) structure. With a reduction temperature of 550 degrees C, the resulting sample was composed of highly pure HEA AlCoCrFeNiV nanoparticles with a BCC structure of 15 nm. Analyses by scanning electron microscopy/transmission electron microscopy with energy-dispersive X- ray spectroscopy confirmed the formation of homogeneous HEA AlCoCrFeNiV with a nanoscale morphology. In the hydrogenation reaction of p-nitrophenol by NaBH4, the AlCoCrFeNiV nanoparticles (produced at 550 degrees C) exhibited a catalytic activity with similar to 90% conversion and 16 kJ/mol activation energy. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

High-entropy alloy nanoparticles were synthesized using a molten salt method, and they exhibited excellent catalytic activity in the hydrogenation reaction of p-nitrophenol.