Crystallinity and interfacial Mo–N–C bond engineered MoS2 embedded graphitic nitrogen doped carbon hollow sphere for enhanced HER activity

To restrain fossil fuel depletion, the need of the hour is the development of efficient, durable, and non-precious electrocatalysts for the hydrogen evolution reaction (HER). The hierarchical nanostructure consisting of transition metal dichalcogenides and graphitic heteroatom-doped carbon with an abundant interfacial M–N–C catalytic site is highly demanding for electrolytic applications. Herein, we report crystallinity-engineered ultrathin MoS2 nanosheets hierarchy over nitrogen-doped graphitic carbon (NC) hollow spheres as a promising material for HER. The well optimized NC@MoS2 demonstrates superior HER activity with a low onset overpotential of 9 mV and an overpotential of 145 mV at a current density of −10 mA cm−2. It exhibits low Tafel slope of 39 mV dec−1 and excellent chronoamperometric stability. Superior HER activity originates from interfacial Mo–N–C bonds. Density functional theory (DFT) calculations unveil that Mo–N–C bonds between MoS2 and NC matrix ease electronic transportation and further diminish Gibbs free energy for HER.