Credit: Terrones Group/Penn State
Molecular models representing a 2D heterostructure made of graphene (gray background hexagonal lattice), and islands on top of hexagonal WS2 and MoS, as well as an alloy of the two. Water (H2O) molecules in red (oxygen) and gray (hydrogen) come from the bottom left hand side and get transformed catalytically after interacting with the heterostructures into H2 bubbles (top right hand side)