Heterogenization of few-layer MoS2 with highly crystalline 3D Ni3S2 nanoframes effectively synergizes the electrocatalytic hydrogen generation in alkaline medium

Molybdenum sulfide (MoS2) has been demonstrated to be a promising candidate to replace precious platinum catalysts for electrocatalytic hydrogen evolution reaction. However, MoS2 typically suffers from unfavorable hydrogen desorption in alkaline solution and their positive HER kinetics largely relies on high overpotentials. Herein, we demonstrate a synergistically structural and electronic modulation strategy to improve the of MoS2. Heterogeneous core-shell structured Ni3S2@MoS2 hollow nanoframe supported on Ni foam has been constructed by a combined three-step hydrothermal/sulfurization/calcination process to achieve three-dimensional hierarchical catalyst with multi-level interfaces. The optimized Ni3S2@MoS2 catalyst presents low overpotentials of 60 mV to reach a current density of -10 mA cm(-2) with Tafel slope of 48 mV dec(-1) in 1.0 M KOH, and a satisfactory stability of 5000-circles of continuous operation. The large enhancement can be attributed to the thermodynamic and kinetic acceleration derived from synergistic effect of highly efficient electronic transmission (smooth heterojunction) and morphological peculiarity (rich active edges). This design provides valuable insights for reengineering electrocatalysts by collaborating promoters toward the optimization of electrocatalytic activity of these unique materials and beyond. (C) 2019 Elsevier Ltd. All rights reserved.