  Hydrogen fuel is an ideal energy source to replace the traditional fossil
fuels because of its high energy density and renewability. Electrochemical
water splitting is also regarded as a sustainable, cleaning and eco-friendly
method for hydrogen evolution reaction (HER), but a cheaper, earth-abundant and
similarly efficient alternative to Pt as an HER catalyst cannot still be
discovered. Recently, 2D Transition Metal Dichalcogenides (TMDs) are
demonstrated to greatly enhance the HER activity. Herein, our work provides an
insight into the recent advances in 2D TMDs-based HER following the
composition-characterisation-construction guideline. After the background
introduction, several research outputs based on 2D TMDs as well as the
comprehensive analysis on the modulation strategies of 2D TMDs, for the
purposes of increasing the active sites, improving the intrinsic activity and
altering the electronic states. Finally, the future opportunities and
challenges of 2D TMDs electrocatalysts are briefly featured.
