Functional Carbon-Directed Synthesis of High-Entropy Alloys with Tuned Structure for Catalysis.

The synthesis of nanoscale high-entropy alloys (nHEAs) with customized elements is severely constrained by the intrinsic immiscibility of metal elements, leading to phase separation. Current methods for making nHEAs via high-temperature treatment or liquid metals often suffer from element selection or particle size control. Herein, we report a carbon-directed methodology that overcomes these limitations by directly modulating the mixing enthalpy. We establish a linear correlation between mixing enthalpy and charge transfer, providing a mechanistic pathway to circumvent element immiscibility. Specifically, hydrogen-substituted graphdiyne (HsGDY), characterized by its unique sp1-sp2 cohybridization, acts as an electron redistributor to exchange electrons with metal atoms, thereby driving the mixing enthalpy toward zero to form nHEAs. This enables HsGDY to outperform conventional sp2 carbons in mediating interface interactions for the growth of nHEAs with tuned particle sizes. This approach is universal, validated by the precise synthesis of 5-15-element nHEAs with ultrasmall size (∼3 nm) at a relatively low temperature of 423 K. The resulting nHEAs exhibit exceptional catalytic activity and stability for the hydrogen evolution reaction (HER), surpassing state-of-the-art benchmarks. This carbon-directed synthesis paradigm paves a new way to high-entropy alloys for catalysis and beyond.