A Fractal-Tip Cu3Ni/NiMoO4 Heterostructure for Efficient Hydrogen Evolution via an Accelerated Volmer–Tafel Mechanism

, promoting water dissociation (H*-*OH). Experimental results and theoretical calculations reveal that the interface lowers the energy barrier for water dissociation and increases H* coverage, shifting the reaction mechanism from the Volmer-Heyrovsky pathway to the more efficient Volmer-Tafel route. Furthermore, the fractal-tip structure boosts HER kinetics by amplifying local electric fields, concentrating protons, and accelerating bubble release. This work provides a rational design strategy for improving hydrogen evolution kinetics through combined structural and interfacial optimization.