Charge-Buffered Sulfidation Stabilized Bδ− in 1T MoS2: Orbital Alignment for Efficient Alkaline Hydrogen Production

The sp 3 hybridization of surface sulfur in metallic phase molybdenum disulfide (1T MoS 2 ) is identified as the intrinsic bottleneck for alkaline hydrogen production (HER), where their electron-saturated nature elevates the kinetic barrier for water dissociation. To overcome this limitation, a charge-buffered sulfidation strategy is reported to stabilize anionic boron (B δ− ) within 1T MoS 2 . By employing molybdenum aluminum boride as the precursor, the B δ− dopants can be efficiently preserved via the topological confinement imposed by Mo─B─Mo network. This approach also maintains the 1T phase integrity through Al-mediated electron compensation. Theoretical and experimental analyses reveal that B δ− substitution generates vertically oriented empty p z orbitals through sp 2 hybridization, which elevates orbital energy to align with molecular orbitals of water, significantly reducing the O─H cleavage barrier by over 80% compared to 1T MoS 2 . Concurrently, the B─Mo─S networks upshift adjacent sulfur 3p band centers to optimize the hydrogen adsorption path. These dual functionalities endow the p z -functionalized 1T MoS 2 with a low overpotential of −30 mV at 10 mA cm −2 , and high-current operation of 1 A cm −2 at 1.779 V in an anion-exchange membrane electrolytic cell. This work not only establishes orbital alignment as a transformative design principle for advanced electrocatalysts, but also paves a novel synthetic pathway for 1T transition metal disulfides.