Hydroxyl Spillover Activated from the Strongly Coupled Ru@Mn3O4 Heterostructure to Promote Alkaline Hydrogen Evolution

Alkaline hydrogen evolution reaction (HER) has great potential in practical hydrogen production. However, constructing an excellent catalyst with advantages of both superior water dissociation ability and easy OH* desorption remains urgently needed and yet challenging for the alkaline HER. Herein, superior water dissociation process, facile OH* desorption, and optimized H adsorption are realized on a strongly coupled heterostructure of Ru@Mn3O4, in which Ru clusters are decorated on Mn3O4 via Ru─O─Mn bonds. The highly oxophilic Mn3O4 facilitates the water dissociation, whereas the formed heterointerface can efficiently desorb OH* via hydroxyl spillover effect and optimize H adsorption. Consequently, the Ru@Mn3O4 presents remarkable HER performance with a low overpotential of 17 mV at 10 mA cm-2 and Tafel slope of 30 mV dec-1, surpassing recently reported Ru-based catalysts and commercial Pt/C. More importantly, the mass activity (MA) and turnover frequency (TOF) of the Ru@Mn3O4 increase about 11- and 8-fold, respectively, compared to Pt/C at 100 mV in 1.0 M KOH. This study provides a new strategy for designing high-performance HER catalysts and enhancing the catalytic performance through hydroxyl spillover effect and sheds a light on understanding the HER mechanism.