Layered high-entropy sulfides: Boosting electrocatalytic performance for hydrogen evolution reaction by cocktail effects

Researchers at Karlsruhe Institute of Technology (KIT) have developed novel high-entropy sulfides (HESs) as catalysts for the hydrogen evolution reaction (HER). These materials contain a combination of iron, manganese, nickel, cobalt as a base, combined with either chromium or molybdenum and they are distinguished by their unique layered structures and enhanced electrochemical properties. The researchers demonstrated that introducing molybdenum into the composition creates a layered structure, which increases the material’s surface area and thereby enhances its catalytic efficiency

As hydrogen is increasingly recognized as a clean energy carrier, efficient and cost-effective catalysts for its production through electrochemical water splitting are essential. Conventional catalysts often rely on precious metals, which are costly and limited in supply, presenting a barrier to large-scale hydrogen production. To address this, the KIT team focused on high-entropy sulfides (HESs), materials composed of multiple transition metals that achieve high electrocatalytic efficiency through a layered structure.

The Solution: A research team at KIT developed HES catalysts based on a unique “cocktail effect” strategy, wherein the simultaneous integration of multiple metals results in synergistic properties. The inclusion of molybdenum in the material promotes a layered structure, increasing the specific surface area and the number of catalytically active sites. The materials, specifically (Fe₀.₂Mn₀.₂Ni₀.₂Co₀.₂Mo₀.₂)S₂, demonstrated outstanding hydrogen evolution performance with minimal overpotential and high stability in alkaline environments.

The Future: This study lays the groundwork for the use of high-entropy sulfides as cost-effective and sustainable alternatives to precious metal catalysts in hydrogen production. Future research could focus on expanding the composition of HESs and optimizing them for even greater stability and efficiency. High-throughput screening methods and machine learning are expected to play a key role in discovering and developing new HESs with tailored properties for electrochemical processes.

The Impact: These findings hold significant potential for sustainable energy solutions. The exceptional efficiency of the HES materials compared to conventional catalysts could greatly improve electrochemical hydrogen production, accelerating the industrial implementation of a hydrogen-based energy economy. The introduction of stable, low-cost catalysts is a crucial step toward a more sustainable energy future.

This work has been recently published in the online edition of Materials Futures, a prominent international journal in the field of interdisciplinary materials science research.

Reference
Ling Lin, Ziming Ding, Guruprakash Karkera, Thomas Diemant, Dong-Hui Chen, Maximilian Fichtner, Horst Hahn, Jasmin Aghassi-Hagmann, Ben Breitung, Simon Schweidler. Layered High-Entropy Sulfides: Boosting Electrocatalytic Performance for Hydrogen Evolution Reaction by Cocktail Effects[J]. Materials Futures, 2024, doi: 10.1088/2752-5724/ad8a78.