(633e) Supported Iridium Catalysts for Low-Cost Water Electrolysis

Iridium catalysts are highly active for the oxygen evolution reaction [1,2]. While iridium shows the best activity, it is expensive and rare, limiting its widespread use. To solve this issue, we considered an approach in which we could use small iridium particles or thin iridium coatings supported over various substrates to enhance the stability and the activity of the supported iridium catalyst [2]. In this research, we used density functional theory to calculate the stability of single iridium atoms, small iridium islands, and a complete iridium overlayer on FCC and BCC transition metal substrates. It was found that BCC metals bind iridium more strongly than FCC metals. Furthermore, we find that the adsorption energy of iridium correlates with substrate d-band center and lattice constant, meaning they can be used as predictive descriptors. By artificially compressing or expanding the substrate by varying its lattice constant, we have quantitatively deconvoluted ligand and strain effects on iridium adsorption. Using these DFT results, we will discuss implications for iridium supported catalyst design for the oxygen evolution reaction.

1 . Lončar, A., Escalera‐López, D., Cherevko, S., & Hodnik, N. (2022). Inter‐relationships between Oxygen Evolution and Iridium Dissolution Mechanisms. Angewandte Chemie International Edition, 61(14) e202114437.

2. Seitz, L. C., Dickens, C. F., Nishio, K., Hikita, Y., Montoya, J., Doyle, A., Kirk, C., Vojvodic, A., Hwang, H.Y., Norskov, J.K., & Jaramillo, T. F. (2016). A highly active and stable IrO x/SrIrO3 catalyst for the oxygen evolution reaction. Science, 353(6303), 1011-1014.