Graphene Supported MoS Structures with High Defect Density for an Efficient HER Electrocatalysts.

The development of novel efficient and robust electrocatalysts with sufficient active sites is one of the key parameters for hydrogen evolution reactions (HER) catalysis, which plays a key role in hydrogen production for clean energy harvesting. Recently, two-dimensional (2D) materials, especially those based upon transition metal dichalcogenides such as molybdenum disulfide (MoS), have gained attention for the catalysis of hydrogen production because of their exceptional properties. Innovative strategies have been developed to engineer these material systems for improvements in their catalytic activity. Toward this aim, the facile growth of MoS clusters by sulfurization of molybdenum dioxide (MoO) particles supported on reduced graphene oxide (rGO) foams using the chemical vapor deposition (CVD) method is reported. This approach created various morphologies of MoS with large edges and defect densities on the basal plane of rGO supported MoS structures, which are considered as active sites for HER catalysis. In addition, MoS nanostructures on the surface of the porous rGO network show robust physical interactions, such as van der Waals and π-π interactions between MoS and rGO. These features result in an improved process to yield a suitable HER catalyst. In order to gain a better understanding of the improvement of this MoS-based HER catalyst, fully atomistic molecular dynamics (MD) simulations of different defect geometries were also performed.