Hierarchical Ultrathin Mo/MoS2(1−x−y)Px Nanosheets Assembled on P, N Co‐Doped Carbon Nanotubes for Hydrogen Evolution in Both Acidic and Alkaline Electrolytes

Abstract Synergistically coupled 1D/2D materials have great potential for energy conversion application due to its high catalytic activity. Herein, an in situ assembly strategy is developed for preparing the P, N co‐doped carbon nanotubes and Mo/MoS 2(1− x − y ) P x nanosheets composites (Mo/MoS 2(1− x − y ) P x @PNC) for hydrogen evolution reactions (HER). The PNC guarantees structural stability and fast charge transfer in a long‐range, while Mo/MoS 2(1− x − y ) P x nanosheets offer a large electrochemically active surface area with embedded metallic Mo in improving its internal conductivity and rich surface/interface properties. Thus, the optimized catalyst (Mo/MoS 1.15 P 0.30 @PNC) possesses more surface active sites and exhibits extraordinary HER activities, with a small overpotential of −79 and −131 mV at 10 mA cm −1 , and low Tafel slope of 49 and 82 mV dec −1 in 0.5 m H 2 SO 4 and 1.0 m KOH, respectively. Density functional theory calculations confirm that the higher substitution of S atoms by P in MoS 2 can form strong Mo 3d‐S 2p‐P 2p hybridizations at Fermi level, resulting in the narrower bandgap and smaller ∆ G H * of hydrogen (H*) adsorption, thereby leading to the promoted HER activity.