TMD/Graphene Foams: Synthesis, Characterization and Their Catalytic Activity for Hydrogen Evolution Reaction

Three-dimensional (3D) architectures made of two dimensional (2D) materials emerged as a promising strategy to obtain the best from these two worlds. While the 3D formation of graphene and several transition metal dichalcogenides (TMDs) was widely reported, the rational formation of complex heterostructures was proven more challenging. Here we present the formation of MoS₂ or WS₂ coated graphene foams using several methodologies. The structural, chemical, optical and catalytic activity for hydrogen evolution reaction (HER) are described and correlated.

The process starts with the synthesis of the 3D Graphene on a commercial Nickel foam, using a well-established chemical vapor deposition (CVD) method. These graphene foams have a high surface area and electrical conductivity. A methodology to improve the control over the porosity is presented. The GF is then used as the template to grow the MoS₂ and WS₂, utilizing several methodologies, such as atomic-layer deposition and the sulfurization of pre-deposited metal, metal oxide or metal sulfide species via wet-chemical approaches. Our study finds significant differences in the structure and morphology of the films which are reflected in their catalytic activity and stability. Therefore, this study presents a very efficient and easy way to create complex MoS₂ and WS2/GF 3D heterostructures to be used in diverse applications and expanded to other TMDs.