Spatial Regulated Noncontact Ru Heterostructure for Cost-Effective Platinum-Free Fuel Cells

Cost-effective Ru holds tremendous promise to tackle the sluggish hydrogen oxidation reaction (HOR) kinetics. Rational spatial distribution design of heterostructure components is crucial for electrochemical reactions involving multiple intermediates, particularly in fuel cells. In this study, we demonstrate a noncontact heterostructure catalyst featuring spatially separated but functionally synergistic ruthenium (Ru) nanoparticles (NPs) and molybdenum carbide (MoC) clusters (CLs) interconnected by a conductive carbon support (Ru-MoC/C) for the alkaline HOR. The experimental results and density functional theory (DFT) calculations demonstrate that this configuration achieves a refined division of labor and seamless collaboration in functionality through its ingenious spatial arrangement. Consequently, the Ru-MoC/C-based anion exchange membrane fuel cell (AEMFC) with an ultralow Ru loading of 0.05 mg_Ru cm^-2 and a Co₂MnO₄/C cathode achieves a remarkable total specific peak power of 17.4 W mg_PGM ^-1 in H₂-air, surpassing the state-of-the-art catalysts. Moreover, this Pt-free AEMFC achieves a total platinum-group-metal (PGM) utilization of 13.4 W mg^-1 at 0.65 V, which surpassing the U.S. Department of Energy (DOE) 2025 target. Additionally, the Ru-MoC/C-based fuel cell can maintain stable cell operation at 0.5 A cm^-2 for over 110 h. This work highlights the promise of noncontact heterostructure design in developing efficient and durable electrocatalysts and beyond.