Designing Pd/O co-doped MoSx for boosting the hydrogen evolution reaction

Molybdenum disulfide has a great potential as electrocatalyst to drive the hydrogen evolution reaction (HER), but HER catalysts based on transition metal (TM) and non-metal (NM) co-doped MoS2 have rarely been reported because of the difficulty of preparation. Herein, we design an upgraded sacrificial-counter-electrode method to create a favorable environment for atomic-scale substitution to synthesize Pd/O co-doped MoSx (Sub-MoSx/CNTs/Pdgly), which exhibits a small overpotential of 23 mV at a current density of 10 mA cm-2, a low Tafel slope of 18 mv dec-1 and good catalytic stability. Density functional theory (DFT) calculations reveal that the Pd/O co-doped MoS2 tends to form defect-pairs (PdMo+OS) in MoS2, and the unsaturated S atoms around the defects enormously promote the HER activity.