Thermodynamically stabilized and driven synthesis of multicomponent high-entropy alloy catalysts for the HER

Abstract

High-entropy alloys (HEAs) show great promise for the hydrogen evolution reaction (HER) due to their tunable electronic structures and strong structural stability. However, most reported HEAs rely on kinetically stabilized structures, which limit the regulation of atomic and electronic structures in HEAs. In this work, a thermodynamically stabilized and driven synthesis method was employed to synthesize HEAs containing 5–15 elements. Structural characterization reveals that all samples adopt a single-phase solid solution structure, with the HEA nanoparticles (NPs) uniformly dispersed on the carbon support surface. Electrochemical tests showed that the catalytic performance of HEAs with the same elements in the HER can be tuned easily by adjusting the parameters in thermal synthesis. This provides a promising and practical pathway toward achieving “infinite” catalytic performance with “finite” metal elements. Furthermore, HEA NPs containing more than 15 types of elements can also be easily prepared. Using the HER as a model reaction, the HER catalytic activity shows regular changes with heat-treatment temperature, heat-treatment time and the number of constituent elements, indicating that the atomic coordination structure, electronic energy levels, etc., in HEAs can be continuously tuned through heat treatment synthesis parameters. For HEAs synthesized via thermodynamic routes with simple elemental mixing, the minimum overpotential for the HER can reach 32 mV, demonstrating that the thermodynamically stability-driven HEA strategy features convenience and universality in HEA synthesis and activity regulation.