Polyoxometalate-derived N@Mo₂C/V₂O₃ cluster heterostructure for accelerated alkaline hydrogen evolution reaction

The hydrogen evolution reaction (HER) in alkaline water electrolysis is fundamentally limited by the high energy barrier associated with water dissociation. Herein, we report the development of self-supported nitrogen-doped molybdenum carbide and vanadium oxide cluster heterostructures (N@Mo₂C/V₂O₃) on carbon fiber paper using organoimido-derivatized molybdovanadate nanoclusters as precursors. Experimental results and theoretical calculations demonstrate that the engineered cluster heterointerfaces significantly reduce the energy barrier of the rate-determining step, accelerating HER kinetics. Moreover, V₂O₃ acts as a cocatalyst that enhances hydrophilicity of the N@Mo₂C/V₂O₃ and, versus pristine N@Mo₂C, facilitates hydrogen desorption from the composite. The optimized N@Mo₂C/V₂O₃ cluster heterostructure exhibits exceptional electrocatalytic performance, delivering a current density of 300 mA·cm⁻² at an overpotential of merely 191 mV and maintaining stability over 400 h of continuous operation. When integrated into an alkaline water electrolyzer, the system requires only 1.94 V to achieve an industrially relevant current density of 500 mA·cm⁻², outperforming commercial platinum–carbon catalysts. These findings offer new perspectives and valuable insights into the development of efficient, stable, and economical noble metal-free electrocatalysts for green hydrogen production.