Unravelling Composition–Activity–Stability Trends in High Entropy Alloy Electrocatalysts by Using a Data‐Guided Combinatorial Synthesis Strategy and Computational Modeling

• Published in: Advanced energy materials Vol. 12; no. 8
• Main Authors: Banko, Lars, Krysiak, Olga A., Pedersen, Jack K., Xiao, Bin, Savan, Alan, Löffler, Tobias, Baha, Sabrina, Rossmeisl, Jan, Schuhmann, Wolfgang, Ludwig, Alfred
• Format: Journal Article
• Language: English
• Published: 01.02.2022
• Subjects: electrocatalysts; high entropy alloys; high‐throughput experimentation; materials discovery
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202103312

High entropy alloys (HEA) comprise a huge search space for new electrocatalysts. Next to element combinations, the optimization of the chemical composition is essential for tuning HEA to specific catalytic processes. Simulations of electrocatalytic activity can guide experimental efforts. Yet, the currently available underlying model assumptions do not necessarily align with experimental evidence. To study deviations of theoretical models and experimental data requires statistically relevant datasets. Here, a combinatorial strategy for acquiring large experimental datasets of multi‐dimensional composition spaces is presented. Ru–Rh–Pd–Ir–Pt is studied as an exemplary, highly relevant HEA system. Systematic comparison with computed electrochemical activity enables the study of deviations from theoretical model assumptions for compositionally complex solid solutions in the experiment. The results suggest that the experimentally obtained distribution of surface atoms deviates from the ideal distribution of atoms in the model. Leveraging both advanced simulation and large experimental data enables the estimation of electrocatalytic activity and solid‐solution stability trends in the 5D composition space of the HEA system. A perspective on future directions for the development of active and stable HEA catalysts is outlined. This work introduces a new concept for the efficient exploration of multinary materials systems such as high entropy alloys. By permutation of the deposition sources in combinatorial co‐sputtering, a large compositional range of a high entropy alloys system is covered. High‐throughput characterization yields a large and consistent dataset that helps to unravel composition–activity–stability trends.