Investigating Spillover Energy as a Descriptor for Single-Atom Alloy Catalyst Design
Ryan T. Hannagan, Ho Yi Lam, Romain Réocreux, Yicheng Wang, Andrew C. Dunbar, Vinita Lal, Volkan Çınar, Yunfan Chen, Prashant Deshlahra, Michail Stamatakis, Nathaniel M. Eagan, E. Charles H. Sykes
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 rate-determining 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.