Constructing 1 T-2 H TaS2 nanosheets with architecture and defect engineering for enhance hydrogen evolution reaction

Tailoring tantalum disulfide (TaS 2 ) electrocatalysts with tunable stacking architecture and phase structure is of great importance for advancement of hydrogen evolution reaction (HER). In this work, stacking architecture- and phase- modulated tantalum disulfide nanosheets are reported through a facile liquid phase synthesis strategy. Accordion-like nanosheets, vertical nanosheets and ultrathin nanosheets are named according to their obvious stacking architecture, and 1T-2H mixed phase structures containing different degrees of 2H phases are realized. High-resolution transmission electron microscopy shows that there are obvious lattice defects in the nanosheets. Tantalum disulfide nanosheets synergistically integrate multiple advantages of nanostructure engineering, phase engineering and defect engineering. In the HER process, the ultrathin tantalum disulfide nanosheet structure is conducive to the in-plane electron transfer, and its close contact with the electrode surface makes the charge transfer faster and has the best HER activity. The overpotential of the ultrathin nanosheet electrocatalyst at 10 mA cm -2 is 280 mV. After 10000 CV cycles and over 40 hours of i-t test, the catalyst still has high stability in acidic media. Theoretical calculations show that the addition of 2H phase structure and rich defects improves the intrinsic activity and active sites, and jointly promotes the improvement of HER performance. Our work integrates a variety of optimal regulation methods into TaS 2 nanosheets, providing a new idea for the construction of advanced electrocatalysts for water electrolysis. • Synthesis of tantalum disulfide nanosheets in liquid phase method. • Tantalum disulfide nanosheets have adjustable architecture and 1T-2H mixed phase structure, and have certain defects. • TaS2 ultrathin nanosheets combined with phase engineering and defect engineering have better HER activity and stability. • DFT studies show that the addition of 2H phase structure and rich defects improves the intrinsic activity of TaS2.