Rapid Screening of Single-Atom Catalyst Synthesis Conditions Using ToF-SIMS and Facet-Dependent Single-Crystal Substrates.

Single-atom catalysts (SACs) offer superior catalytic performance compared with traditional nanoparticle catalysts but are challenging to develop because of the need for extensive optimization and specialized characterization techniques. This study presents a rapid and versatile method for detecting synthesis conditions and elucidating the deposition mechanisms of SACs on various substrates. By depositing active elements (Au, Cu, Ni, and Rh) on facet-specific single-crystalline substrates (CeO, TiO, MgO, and AlO) and employing time-of-flight secondary ion mass spectroscopy (ToF-SIMS), we assessed facet-dependent deposition behaviors and identified optimal conditions for solution-based SAC synthesis. ToF-SIMS revealed diverse deposition behaviors depending on the active element, substrate type, and facet, including the formation of single-atom sites, aggregation into clusters, or absence of deposition altogether. These findings, which align with previous reports on specific systems, highlight the technique's ability to rapidly differentiate these outcomes across various materials. Our study demonstrates that ToF-SIMS is a viable tool for the rapid screening of synthesis conditions, contributing to the faster and more efficient development of next-generation single-atom catalysts.