In situ synthesis of edge-enriched MoS2 hierarchical nanorods with 1T/2H hybrid phases for highly efficient electrocatalytic hydrogen evolution

As a promising electrocatalyst, MoS2 has attracted significant attention for application in the hydrogen evolution reaction (HER). However, the shortcomings such as limited active sites and the inherently low electroconductivity of the 2H-phase MoS2 restrain its application. Tuning of the phase composition (from 2H to 1T phase) and the microstructure of MoS2 have been proposed as effective strategies to improve the catalytic activity of MoS2. However, complicated chemical exfoliation and morphology regulation are generally involved in these process. Herein, we developed a facile hydrothermal method to in situ synthesize hierarchical MoS2 nanorods with mixed 1T and 2H phases. The coexisting 1T phase can provide more active sites and improve the electronic conductivity of the nanorods. In addition, the Schottky barriers formed at the boundaries of the 1T and 2H phases can improve the conductivity. Moreover, the hierarchical structure can improve the contact area between the MoS2 catalyst and the electrolyte, and the rod-like one-dimensional structure of the catalyst favors fast charge transfer and ion diffusion. Due to these unique properties, the as-synthesized MoS2 nanocatalyst exhibits excellent HER performance with a small overpotential of 156 mV at 10 mA cm−2, a small Tafel slope of 47.9 mV per decade, and robust stability. This study provides a guideline for the design of an electrocatalyst with high HER performance in multiscale principles.