MO _x /Rh Metallene with Energetic Interfaces as Efficient Bifunctional Electrocatalyst for Durable Water Splitting

ABSTRACT Developing excellent activity and stability bifunctional electrocatalysts for alkaline water splitting remains challenging. This work constructs ultrathin MO _x /Rh metallene heterostructures (M = Fe, Co, Ni) via atmosphere‐controlled solvothermal synthesis, achieving uniform MO _x nanoclusters on Rh metallene with optimized interfaces. The FeO _x /Rh catalyst demonstrates exceptional bifunctional activity, requiring only 1.53 V for overall water splitting at 10 mA cm ⁻² with robust durability. Leveraging the unique oxygen‐affinity of FeO _x and its strong electronic coupling with Rh, this study reveals the critical role of the high‐energy interface in accelerating the kinetics of the rate‐limiting four‐electron oxygen evolution reaction. Mechanistic insights reveal that FeO _x promotes water dissociation via optimized orbital hybridization, while electronically modulated Rh optimizes hydrogen adsorption (ΔG _H* = ‐0.057 eV) via d‐band downshifting. This interfacial engineering strategy enables efficient solar‐driven hydrogen production, offering a sophisticated paradigm for designing high‐performance bifunctional metallene catalysts.