Robust Interfacial Hydrogen-Bond Network on Positively Charged Ru-N-Ni Dual Sites Boosts Alkaline Hydrogen...

Ruthenium (Ru)-based dual-site catalysts can efficiently accelerate alkaline hydrogen electrocatalytic kinetics by virtue of the well-balanced competitive adsorptions of multiple reaction intermediates. However, their insufficient mass transfer makes them far away from the applications, largely lying to the challenge of precisely manipulating the interface water structure. Herein, a concept of nitrogen-bridged positively charged dual sites with a robust interfacial hydrogen-bond network is presented for enhancing alkaline hydrogen oxidation and evolution reactions (HOR and HER). The positively charged Ru and Ni sites are demonstrated to trigger the ordered water orientation with the favorable "O-down" configuration, strengthening the interfacial hydrogen-bond network and promoting the mass transfer. In particular, the efficient charge-transfer channels of asymmetric Ru-N-Ni bridges can maintain the high-valence of Ru sites and high electron density of Ni sites, thus stabilizing ^*OH adsorption on Ru sites and weakening ^*H adsorption on Ni sites, as well as enhancing anti-CO poisoning ability. As a result, the elaborated Ru-Ni₃N catalysts achieve a mass activity of 60.6 A g^-1 for HOR, representing one of the most active one among state-of-the-art Ru-based catalysts yet reported. This interfacial hydrogen-bond network modulation strategy can also be extended to HER electrocatalysis, driving the anion exchange membrane water electrolyzer to achieve a low cell voltage of 1.79 V at 1 A cm^-2 and excellent long-term stability at an industrial current density of 500 mA cm^-2 for more than 550 h.