Enhanced electrocatalytic water splitting performance and stability of MnO₂ through Ru doping

The development of efficient and durable bifunctional electrocatalysts based on earth-abundant elements for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is critical for advancing sustainable hydrogen production. Herein, a facile one-step hydrothermal strategy was developed to synthesize Ru-doped α-MnO 2 nanoneedles grown on carbon paper (Ru 0.02 MnO 2 /CP) as a novel bifunctional electroccatalyst. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses revealed that Ru incorporation induces uniform lattice distortion in MnO 2 , significantly increasing the density of oxygen vacancies and catalytically active Mn 3+ sites. The structural modifications enhance the intrinsic electrochemical activity and structural stability of MnO 2 during HER/OER in alkaline media. The optimized Ru 0.02 MnO 2 /CP catalyst exhibited exceptional bifunctional performance, achieving low overpotentials of 107 mV (HER) and 261 mV (OER) at 10 mA cm −2 . Furthermore, stability testing under continuous operation reveals <6 % activity loss over 100 h at 10 mA cm −2 . Density functional theory (DFT) calculations revealed that Ru doping optimizes the adsorption/desorption energetics of reaction intermediates (*H for HER; *OH for OER), effectively lowering the kinetic barriers and overpotentials for both half-reactions. This work provides a rational strategy for designing high-performance and cost-effective bifunctional electrocatalyst, advancing their potential application in scalable water electrolysis for sustainable hydrogen production.