2D MOF Structure Tuning Atomic Ru Sites for Efficient and Robust Proton Exchange Membrane Water Electrolysis

Abstract Developing cost‐effective ruthenium (Ru)‐based HER electrocatalysts as alternatives to commercial Pt/C is crucial for the advancement of proton exchange membrane water electrolysis (PEMWE). However, the strong hydrogen adsorption of Ru‐based catalysts restricts its activity. Herein, a strategy is reported to tune the electronic structure and improve mass transfer by implanting Ru atoms onto the (002) facet of two‐dimensional zeolitic imidazolate framework‐67 (Ru@LZIF₍₀₀₂₎) to optimize the d‐band center (ε_d) of Ru and the hydrogen spillover behavior. Benefiting from the ultrathin nanosheet structure and optimized ε_d of Ru, the over‐strong H adsorption energy is weakened and the electron/mass transfer is facilitated. Ru@LZIF₍₀₀₂₎ exhibits an overpotential of 9.2 mV at 10 mA cm⁻² and a long‐lasting stability of 35 days at 100 mA cm⁻². The mass activity and price activity of Ru@LZIF₍₀₀₂₎ is 2.9 and 14.7 times higher than Pt/C, respectively. More impressively, Ru@LZIF₍₀₀₂₎ delivers a cell voltage of 2.01 V at a high current density of 4 A cm⁻² in PEMWE. The excellent long‐term durability of 1200 hours operating at 4 A cm⁻² with an ultralow decay rate of 7.5 × 10⁻³ mV h⁻¹ has been achieved, making it promising as a cost‐effective alternative to Pt/C catalyst for PEMWE applications.