2D Materials for Energy Applications

2D materials are studied for their role both as a scaffold support and as a catalyst for fuel cells and hydrogen production by water splitting. Graphene based materials are explored for their application as porous electrodes that have high surface area and good conductivity. Transition metal dichalcogenide, MoS2, is investigated as a catalyst for the hydrogen evolution reaction. Hybrid Pt:MoS2 systems are also fabricated to achieve unique 3D catalytic films for a wide range of applications. The 2D materials are typically grown by chemical vapour deposition (CVD), and the Pt nanoparticles are produced directly on the surface of 2D materials by a controlled templated growth process, which gives epitaxial interfaces and strong coupling.

CVD of 3D porous conducting electrodes based on 2D materials

We have recently started expanding graphene from planar 2D structures to 3D networked scaffolds. This is achieved by using porous 3D catalytic foams that help template the growth in 3D. Removing the catalyst through chemical etching leaves a porous 3D structure consisting of continuously connected graphene sheets that retain high electrical conductivity. The thickness of the graphene layers can be controlled by reaction conditions. These graphene scaffolds can be used as electrodes in energy applications such as Fuel cells and Batteries, as catalyst supports for hydrogen reactions. We study how to integrate new inorganic materials with these 3D graphene structures. The figure below shows a SEM image of a freestanding porous 3D graphene network with visible wrinkling of the sheets.

Pt nanocrystals on monolayer MoS2

Single Pt atom migration on MoS2 surface

Edge Rich MoS2 Films

CVD is used to grow thin porous films of MoS2 platelets that are edge rich. They show excellent potential for HER catalysis. The unique 3D:2D structure provides a high density of edges within a geometrical area, maximizing physical area usage of electrodes.