Electrostatically Guided Covalent Architectures for Stable Hydrogen Evolution at Ampere‐Level Current Densities in Acidic Media

ABSTRACT Achieving stable operation at high current densities is a critical challenge for acidic water electrolysis, where intensified bubble evolution induces concentration polarization and mechanical stress that accelerate catalyst degradation. Here, we report Mo ₂ C nanoclusters in situ anchored onto nitrogen‐doped carbon nanotubes (NCNTs) via strong Mo─C and Mo─N covalent bonds. The covalent integration, achieved through electrostatically guided self‐assembly followed by carbonization, yields a porous and conductive network that combines efficient charge transport with resistance to acidic corrosion. The resulting catalyst delivers overpotentials of 256 mV at 500 mA cm ⁻² and 396 mV at 1000 mA cm ⁻² in 0.5 m H ₂ SO ₄ , and operates stably at 865 mA cm ⁻² for over 240 h. In a proton exchange membrane water electrolyzer, it sustains overall water splitting at 1000 mA cm ⁻² with a cell voltage of 2.03 V for more than 150 h. This hierarchical covalent design enhances conductivity, durability, and bubble management, representing a scalable strategy for next‐generation electrocatalysts capable of ampere‐level operation in acidic media.