Synthesis of High‐Entropy‐Alloy Nanoparticles by a Step‐Alloying Strategy as a Superior Multifunctional Electrocatalyst

Abstract

High‐entropy‐alloy nanoparticles (HEA‐NPs) have attracted great attention because of their unique complex compositions and tailorable properties. Further expanding the compositional space is of great significance for enriching the material library. Here, a step‐alloying strategy is developed to synthesis HEA‐NPs containing a range of strongly repellent elements (e.g., Bi–W) by using the rich‐Pt cores formed during the first liquid phase reaction as the seed of the second thermal diffusion. Remarkably, the representative HEA‐NPs‐(14) with up to 14 elements exhibits extremely excellent multifunctional electrocatalytic performance for pH‐universal hydrogen evolution reaction (HER), alkaline methanol oxidation reaction (MOR), and oxygen reduction reaction (ORR). Briefly, HEA‐NPs‐(14) only requires the ultralow overpotentials of 11 and 18 mV to deliver 10 mA cm−2 and exhibits ultralong durability for 400 and 264 h under 100 mA cm−2 in 0.5 m H2SO4 and 1 m KOH, respectively, which surpasses most advanced pH‐universal HER catalysts. Moreover, HEA‐NPs‐(14) also exhibits an impressive peak current density of 12.6 A mg−1Pt in 1 m KOH + 1 m MeOH and a half‐wave potential of 0.86 V (vs RHE.) in 0.1 m KOH. The work further expands the spectrum of possible metal alloys, which is important for the broad compositional space and future data‐driven material discovery.

Intermetallic Nanocrystals for Fuel-Cells-Based Electrocatalysis

“…High-entropy alloys can be macroscopically defined as a novel material containing five or more dominant elemental components, of which the atomic percentage of constituent elements varying from 5% to 35%. − Due to the four-core effect, including high-entropy effect, lattice distortion effect, sluggish diffusion effect, and cocktail effect, high-entropy alloys have been widely applied in the field of biomedical materials, aerospace engineering, photothermal conversion, building materials, and magnetocaloric response, etc. − Especially, the continuous adjustment of the surface electronic structure on high-entropy alloys in nanoscale stimulates the development of heterogeneous catalysis. − High-entropy intermetallics, as a brand new concept, can integrate the advantages of high-entropy alloys and intermetallics, thus becoming an important supplement to high-entropy alloys and intermetallics and further enhancing the electrocatalytic activity and stability (Scheme a). − Although the ordered structure is an important feature of intermetallics different from disordered solid-solution alloys, the site occupancy in each sublattice of high-entropy intermetallics is still random or nearly random due to the more constituent elements than sublattices (Figure a).…”

High-entropy alloys in electrocatalysis: from fundamentals to applications

“…To meet the needs of industrial applications, emphasis should be placed on achieving lower cost and higher productivity to facilitate large-scale production. Fortunately, recent advancements in synthesis methodologies, such as liquid metal reaction media, 147 template-directed synthesis, 114 and the step-alloying strategy, 148 have yielded significant breakthroughs. Despite ongoing research in this area, the synthesis of HEAs remains a challenging task, and there is a need for further development of efficient, economical, and controllable methods for producing high-performance and highly active HEAs.…”

Challenges and opportunities in 2D high‐entropy alloy electrocatalysts for sustainable energy conversion

“…developed a stepwise alloying strategy using Pt‐rich nuclei formed during the first phase reaction as the second thermal diffusion seed. This approach successfully led to the synthesis of HEAs containing a number of strongly repulsive elements, such as Bi‐W 60 . The intricate interplay between the 2D material properties, high‐entropy effects, and atomic size differences in these nanomaterials presents exciting opportunities for tailored design and control over their properties.…”

“…In CVD theory, two or more gaseous precursors are introduced into a reaction chamber, where they undergo chemical reactions between atoms and molecules to form a new material that is deposited onto the surface of a substrate. This process is the basis of a traditional thin film technology 60 . CVD encompasses various methods, including atmospheric pressure chemical vapor deposition, plasma‐assisted chemical vapor deposition, laser‐assisted chemical vapor deposition, metal organic compound deposition, among others.…”