Charge-Buffered Sulfidation Stabilized B in 1T MoS: Orbital Alignment for Efficient Alkaline Hydrogen Production.

The sp hybridization of surface sulfur in metallic phase molybdenum disulfide (1T MoS) 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) within 1T MoS. By employing molybdenum aluminum boride as the precursor, the B 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 substitution generates vertically oriented empty p orbitals through sp 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. Concurrently, the B─Mo─S networks upshift adjacent sulfur 3p band centers to optimize the hydrogen adsorption path. These dual functionalities endow the p-functionalized 1T MoS with a low overpotential of -30 mV at 10 mA cm, and high-current operation of 1 A cm 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.