Hard Materials Seminar - "Computational Design and Experimental Synthesis of Cu-doped Intermetallic Single-Atom Alloys"

Traditional single-atom alloys (SAAs) are a novel class of heterogeneous catalysts where dilute active metal dopants are atomically dispersed in a less reactive host metal matrix for selective catalysis. Traditional SAAs use expensive metal dopants and suffer from poor thermodynamic stability due to high surface energy and thermal migration, leading to dopant aggregation and reduced catalytic activity. Recently, intermetallic compounds have been proposed as an alternative to traditional SAAs, offering enhanced atomic-site isolation and thermodynamic stability through the formation of stoichiometric long-range ordered crystal structures to control the spacing and local coordination of active metal dopants, allowing for tunability in the electronic density of states. In this study, we computationally searched for stable binary hosts for more active transition metal dopants that produced an enhanced density of states near the Fermi energy. We found that InAg3 and Ag3Sb doped with dilute copper produce a density-of-states spike near the Fermi energy from the dopant d-orbital, as modeled by density functional theory (DFT) calculations. We synthesized millimeter-sized samples of the intermetallic InAg3 and Ag3Sb binaries doped with dilute copper and characterized the samples using X-ray diffraction (XRD) to verify the desired prototype crystal structure formation, and performed copper dopant verification and distribution analysis through scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Our results offer alternatives for stable SAA compounds with dispersed metal dopants, opening a new route for intermetallic usage in SAAs for experimental catalysis testing.