(296f) Correlating Structural and Electronic Properties of Ultra-Small, Atomically Precise Nanostructures with Electrocatalysis

Thiolate-protected gold nanoclusters (TPNCs) are ultra-small nanostructures (~1 nm diameter) that possess unique molecular-type electronic structures and have applications ranging from biomedicine to catalysis. Owing to their atomically precise structure (i.e. exact chemical formula, Au_n(SR)_m), density functional theory (DFT) calculations can accurately probe the origin of their remarkable properties. Recent experimental efforts have led to the successful heterometal doping of these TPNCs with atomic precision, thus expanding their materials space and applicability in various fields. For instance, palladium (Pd) and cadmium (Cd) doping has been shown to significantly enhance the catalytic activity and selectivity for the electrochemical CO₂ reduction reaction (CO₂RR) to produce CO. Despite numerous studies that have confirmed the high activity of TPNCs for CO₂RR and other electrochemical reduction reactions such as oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER), there exists a lack of consensus on the origin of their electrocatalytic activity. Furthermore, a systematic approach to screen TPNCs as potential electrocatalysts is missing. Herein, we introduce a methodology to screen TPNCs for their use as catalysts in various electrochemical reduction reactions. First, we performed DFT calculations on a series of TPNCs of various size (21 – 279 Au atoms), shape (FCC, HCP kernels), and metal composition (e.g. Ag-, Hg-, Cd-doped). Using our library of optimized TPNCs, we systematically connected structural properties such as size, ligand type, and dopant concentration/position to TPNC electronic properties, including electron affinity and ionization potential. Finally, leveraging experimental results from literature, we elucidate the role of TPNC electronic properties on catalytic performance for electrochemical reduction reactions. Overall, our work connects structure, property, and activity of TPNCs and accelerates nanocatalyst design by avoiding costly trial and error experimentation in the lab.