Unraveling the dominance of intrinsic catalytic activities over electrical properties in electrocatalytic performance of two-dimensional chromium chalcogenide nanosheets

In this study, we synthesized a new category of materials, 2D Cr₂X₃ (where X = S, Se, and Te), using an APCVD method. By leveraging the same space group and identical exposed facets of the as-synthesized Cr₂X₃ nanoflakes, we compared their catalytic performance for HER and electrical properties to unveil the contribution of electrical conductivity in the overall performance. A descending trend in HER activities from Cr₂S₃ to Cr₂Se₃, and Cr₂Te₃ was found, as evidenced by the increasing overpotentials and decreasing current densities at the same overpotential. Interestingly, electrical properties showed an improving trend from Cr₂S₃ to Cr₂Se₃, and Cr₂Te₃, as revealed by I_DS-V_G and I_DS-V_DS tests based on FET devices, respectively. The primary factor affecting overall catalytic performance was found to be intrinsic catalytic activities rather than electrical properties, as supported by DFT calculations. These insights emphasize that the focus of harnessing intrinsic catalytic activities when exploring 2D electrocatalysts.