(581b) Single-Atom Alloys for Oxidation: Computational Design and Experimental Validation

Single-atom alloys have shown strong catalytic performance for several types of reactions, including hydrogenation reactions and alkane conversion. However, single-atom alloys have not been extensively studied for oxidation reactions, despite the critical importance of these reactions. The possibility that single-atom alloys could easily activate molecular oxygen but bind O relatively weakly makes them intriguing, as weakly bound O is likely to be quite reactive. In this work, we computationally designed single-atom alloys for oxidation, focusing on surfaces that can easily activate O₂ but give relatively weak O binding. We found several Ag- and Au-based single atom alloys can activate O₂ with very low barriers, in some cases near 0, while still binding O relatively weakly. Subsequent experimental synthesis and testing of single-crystal single-atom alloy surfaces shows that single-atom alloys can activate O₂ and O can subsequently spillover onto the inert host sites. Characterization with X-ray photoelectron spectroscopy, scanning tunneling microscopy, and temperature-programmed desorption gives strong fundamental insight into the interaction of these materials with oxygen and their state when exposed to oxygen and a reductant. Finally, single-atom alloy nanoparticles were synthesized and tested, and show excellent performance for oxidation reactions. This work demonstrates the utility of integrated computational-experimental studies, and opens up the possibility of high-performance single-atom alloy catalysts for many oxidation reactions.