摘要
Recent experimental and theoretical studies have demonstrated that two-dimensional (2D) transition metal dichalcogenide (TMDC) nanoflakes are one of the most promising candidates for non-noblemetal electrocatalysts for hydrogen evolution reaction (HER). However, it is still challenging to optimize their conductivity and enrich active sites for highly efficient electrochemical performance. Herein, we report a chemical vapor deposition (CVD) and thermal annealing two-step strategy to controllably synthesize hybrid electrocatalysts consisting of metallic NbS 2 nanoflake backbones and a highly catalytic active MoS x nanocrystalline shell on polished commercial glass carbon (GC). In addition, the amount of MoS x in the hybrids can be easily adjusted. We first demonstrate that a small amount of MoS x significantly promotes the HER activity of 2D NbS 2 nanoflakes, which is in good agreement with the density functional theory (DFT) calculation results. Moreover, the optimized MoS x @NbS 2 /GC electrocatalyst displays superior HER activity with overpotential of -164 mV at -10 mA cm -2 , a small Tafel slope of 43.2 mV dec -1 , and prominent electrochemical stability. This study provides a new path for enhancing the HER performance of 2D TMDC nanoflakes.