Tuning the Electrocatalytic Properties of Trimetallic Pentlandites: Stability and Catalytic Activity as a Function of Material Form and Selenium Concentration

Pentlandites are one possible cost-effective alternative to platinum group metals for green hydrogen production. This study delves into the catalytic performance of trimetallic pentlandite systems, exploring the influence of selenium concentration and material form on their efficiency by combining the investigation of materials in various forms (powder catalysts, ingots, and highly densified pellets) with a computational investigation. The experimentally observed solubility limit of selenium was clarified based on the formation energies approach. The best and most stable defect combination, namely, Se:S substitution and S vacancy, was identified and correlated with improved catalytic properties of the systems with small Se addition. Further findings highlight the evolving importance of intrinsic material properties, such as bond properties, intermetallic interactions, or electronic structure, over surface effects, including the activation process, as the material density increases. The research contributes valuable insight into the intricate mechanisms governing pentlandite catalysis. Understanding these dynamics allows for intentional modifications, advancing the application of pentlandites in hydrogen production