Atomically precise Cu14 and Cu13 nanoclusters for oxygen evolution reaction: One additional Cu atom matters

Abstract

Atomically precise coinage metal nanoclusters have been widely explored as model catalysts to study the structure-performance relationship, yet single atom addition onto the metal core to tailor the catalytic properties still remains challenging. Herein, we report a pair of atomically precise Cu nanoclusters, namely [Cu14(Fur)3(PPh3)8H10]+ and [Cu13(Nap)3(PPh3)7H10]0 (hereafter referred to as Cu14 and Cu13, Fur: 2-methyl-3-furanthiolate, Nap: 1-naphthalene thiolate), which exhibit an astonishingly high degree of structural similarity, differing merely by the addition of a single Cu atom yet possessing drastically different catalytic performance toward oxygen evolution reaction (OER). Specifically, in 1 M KOH solution, Cu14 has a much lower overpotential than Cu13 (306 mV vs. 382 mV) to afford a current density of 10 mA cm-2, a smaller Tafel slope and a lower charge transfer resistance. Density functional theory calculations were employed to further identify the catalytic acitve site, confirming that the additonal Cu atom in Cu14 is the key catalytic site which can significantly lower the energy barrier of the rate determining step in OER. This study highlights the crucial role of single-atom addition in modulating the properties and functionalties of atomically precise metal nanoclusters, shedding light on future catalyst design.