Engineering 2D Metal-Organic Framework/MoS_2 Interface for Enhanced Alkaline Hydrogen Evolution

摘要

2D metal-organic frameworks (MOFs) have been widely investigated for electrocatalysis because of their unique characteristics such as large specific surface area, tunable structures, and enhanced conductivity. However, most of the works are focused on oxygen evolution reaction. There are very limited numbers of reports on MOFs for hydrogen evolution reaction (HER), and generally these reported MOFs suffer from unsatisfactory HER activities. In this contribution, novel 2D Co-BDC/MoS_2 (BDC stands for 1,4-benzenedicarboxylate, C_8H_4O_4) hybrid nanosheets are synthesized via a facile sonication-assisted solution strategy. The introduction of Co-BDC induces a partial phase transfer from semiconducting 2H-MoS_2 to metallic 1T-MoS_2. Compared with 2H-MoS_2, 1T-MoS_2 can activate the inert basal plane to provide more catalytic active sites, which contributes significantly to improving HER activity. The well-designed Co-BDC/MoS_2 interface is vital for alkaline HER, as Co-BDC makes it possible to speed up the sluggish water dissociation (rate-limiting step for alkaline HER), and modified MoS_2 is favorable for the subsequent hydrogen generation step. As expected, the resultant 2D Co-BDC/ MoS_2 hybrid nanosheets demonstrate remarkable catalytic activity and good stability toward alkaline HER, outperforming those of bare Co-BDC, MoS_2, and almost all the previously reported MOF-based electrocatalysts.