Atomically precise Ru-O-Ru clusters for enhanced water dissociation in alkaline hydrogen evolution

Atomic clusters typically exhibit distinctive electronic structures and physicochemical properties. However, as the size decreases, their ability to adsorb and dissociate water also diminishes, thereby affecting chemical reactions involving water molecules. Enhancing the adsorption and dissociation capabilities of atomic clusters towards water molecules and elucidating the mechanisms underlying their performance enhancement have become important research directions. Herein, employing the carrier-anchored strategy, Ru-O-Ru atomic clusters were prepared and displayed excellent activity and durability in the hydrogen evolution reaction. Specifically, the Ru-O-Ru atomic clusters exhibited only 86 mV overpotential at 100 mA·cm⁻² and superior membrane-electrode-assembly activity than commercial Ru/C catalyst. Synchrotron radiation-based Fourier transform infrared spectroscopic measurements revealed that the modification of oxygen in Ru-O-Ru units promoted the reorientation of water molecules from a H-up orientation to H-down, therefore, enhanced the formation of strong hydrogen-bond network of interfacial water on the surface of Ru-O-Ru clusters, leading to enhanced adsorption and dissociation of water and accelerated Volmer step. Those findings provide a potential strategy and deep insights for the development of atomic clusters in electrocatalysts.