Solvent Dynamics‐Limiting Effect Facilitates the Construction of Homoatomic Heterophase Fcc/Hcp‐Ru Interface for pH‐Universal Hydrogen Evolution Reaction

Abstract Constructing homoatomic heterophase interfaces (e.g., fcc/hcp‐Ru) enhances catalytic performance by reducing interfacial potential barriers and enabling efficient charge transfer through uniform composition and near‐perfect lattice matching. However, synthesizing metastable noble metals like Ru remains challenging due to strong metallic bonding. Herein, a solvent dynamics‐limiting effect is proposed to regulate the dynamics of nucleation and growth processes to achieve the precise synthesis of metastable metal fcc‐Ru. Furthermore, on the basis of the solvent dynamics‐limiting effect, the construction of metastable/stable homoatomic fcc/hcp‐Ru heterophase interface is successfully realized through a dynamic slow phase transformation strategy. The experimental result shows that the generation of homoatomic heterophase interfaces combines the superiority of different crystal phases and enhances intrinsic activity and stability, thus promoting efficient HER performance in a wide pH range. Specifically, overpotentials as low as 17.1/22.9/22.6 mV are required to achieve 10 mA cm −2 current density in alkaline/neutral/acidic conditions with significantly improving stability. Theoretical calculations demonstrate that the construction of homoatomic heterophase interfaces reduces the dissociation energy of water, optimizes the catalyst's adsorption capacity for hydrogen, thereby promoting an efficient HER pathway. Moreover, the proposed method has potential applications for other metals and oxides, offering new insights for crystal phase engineering.