Carbonaceous-assisted confinement synthesis of refractory high-entropy alloy nanocomposites and their application for seawater electrolysis.

Refractory high-entropy alloy nanocomposites (HEA-NPs) are important class of materials with unique structure and potential applications. Although several synthetic methods have been reported, developing novel routes to prepare nanoscale HEA-based catalysts facilely is still urgently desired. This work takes advantage of confinement assisted arc and plasma shock (APS) to prepare a series of HEA-NPs by regulating the type and proportion of metal precursors. The phase constitutes and morphology of the HEA-NPs are fully characterized. The prepared refractory HEA-NPs possesses five highly dispersed metal components, including titanium (Ti), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo) and simultaneously exhibits an uniform hexagonal morphology of nanocrystals. By taking advantage of its unique corrosion resistance, TiNbTaCrMo HEA-NPs can function as a promising candidate for electrocatalytic hydrogen evolution reaction (HER) in natural seawater. And its catalytic performance after alloying is significantly enhanced compared with the elemental metal. Theoretically, the promoted HER activity can be attributed to the strong adsorption for the various metal components in HEA-NPs caused by the upshifting d-band center close to the Fermi level. Furthermore, this confinement strategy can be further extended to synthesize other HEA-NPs. Our strategy provides a novel method to synthesize various HEA-NPs for further catalytic application.