Rational Framework Engineering of 1T′ Mo–Re Sulfides with Optimized Orbital Hybridization for Efficient Acidic Hydrogen Evolution

Metallic 1T-phase MoS₂ is a promising alternative to platinum-group catalysts for the acidic hydrogen evolution reaction (HER), yet its metastable nature severely limits practical application. Here we present a framework-stabilization strategy for constructing 1T'-phase Mo-Re sulfides by employing the intrinsically distorted 1T' lattice of ReS₂ as a structural scaffold. Preferential Mo substitution at Re sites, facilitated by its low formation energy, enables the formation of Re_0.5Mo_0.5S₂ with a high-purity 1T' architecture free of secondary phases. Combined theoretical and experimental investigations reveal that Mo incorporation triggers directional electron transfer and strong Mo 4d/Re 5d/S 3p orbital hybridization, which redistribute charge density, elevate the S 3p band center, and fine-tune the hydrogen adsorption-desorption equilibrium. Consequently, Re_0.5Mo_0.5S₂ achieves exceptional acidic HER performance with a low overpotential of 113 mV at 10 mA cm^-2 and remarkable stability exceeding 50 h. This work establishes a versatile paradigm for stabilizing metastable transition metal dichalcogenides, providing new insights into the rational design of metastable functional materials.