Investigating Spillover Energy as a Descriptor for Single-Atom Alloy Catalyst Design

Abstract

The identification of thermodynamic descriptors of catalytic performance is essential for the rational design of heterogeneous catalysts. Here, we investigate how spillover energy, a descriptor quantifying whether intermediates are more stable at the dopant or host metal sites, can be used to design single-atom alloys (SAAs) for formic acid dehydrogenation. Using theoretical calculations, we identify NiCu as a SAA with favorable spillover energy and demonstrate that formate intermediates produced after the initial O−H activation are more stable at Ni sites where ratedetermining C−H activation occurs. Surface science experiments demonstrated that NiCu(111) SAAs are more reactive than Cu(111) while they still follow the formate reaction pathway. However, reactor studies of silica-supported NiCu SAA nanoparticles showed only a modest improvement over Cu resulting from surface coverage effects. Overall, this study demonstrates the potential of engineering SAAs using spillover energy as a design parameter and highlights the importance of adsorbate−adsorbate interactions under steady-state operation.

Effect of Bystander Hydrogen Atoms on Hydrogen Desorption on Single-Atom Alloy Surfaces: Insights from Simulated Temperature-Programmed Desorption Spectra

“…Single-atom alloy (SAA) catalysts, in which a reactive metal element is atomically dispersed in another relatively inert metal host, not only exhibit unique and excellent catalytic properties but also maximize the efficiency of atom utilization. − Due to the simplicity and clarity of their structures − and the well-established preparation methods, − SAAs provide an ideal platform for combining simulations and experiments to jointly elucidate microscopic processes and underlying mechanisms. ,− The SAA catalysts have been widely used in heterogeneous hydrogenation ,− and dehydrogenation ,− reactions. A thorough study of the interaction patterns between SAA surfaces and adsorbed molecules as well as the related elementary surface processes is of great importance for establishing the corresponding structure–property relationship. , …”