Rapid hydrogen adsorption-desorption at sulfur sites via an interstitial carbon strategy for efficient HER on MoS2

Molybdenum disulfide (MoS₂), a noble-free material with plentiful unsaturated active edge sites, is expected to replace platinum catalysts for commercial electrocatalytic hydrogen production. However, efficient hydrogen adsorption-desorption processes on sulfur sites with full electron configuration still remain a challenge. Here, vertically oriented self-assembled metallic MoS₂ nanospheres anchored by interstitial atomic carbon (C_ia-MoS₂) are proposed to achieve a rapid hydrogen adsorption-desorption process. In 0.5 M H₂SO₄ solution, C_ia-MoS₂ exhibits fast kinetics (Tafel slope of 45 mV dec⁻¹ and overpotential of 87 mV at 10 mA cm⁻²), as well as a long-term durability over 72 h. As confirmed from X-ray absorption fine spectroscopy and density functional calculations, C_ia significantly optimizes the overall HER performance by reconfiguring the charge landscape and re-splitting the energy level of surface S moiety, which provides a universal strategy for fabricating stable unsaturated 2D catalysts toward HER.