A symmetric SnS2/Graphene/SnS2 sandwich heterostructure as an efficient electrocatalyst for the hydrogen evolution reaction

This study utilized a simple hydrothermal method to synthesize a SnS 2 /Graphene/SnS 2 sandwich heterostructure for the hydrogen evolution reaction. The findings indicated that increasing the graphene content (SnS 2 /Graphene/SnS 2 -2) results in catalytic performance characterized by a higher overpotential, fewer accessible active sites, and a steeper Tafel slope. These results suggest that while graphene enhances conductivity and charge transfer, excessive amounts can negatively impact overall catalytic effectiveness. First-principles calculations of adsorption energy per atom revealed decreased energies at low reduced graphene oxide (rGO) loading on H 2 -adsorbed SnS 2 /rGO heterostructures. These findings align with the experimental data and indicate that low graphene concentration promotes moderate-to-low adsorption in the SnS 2 /Graphene/SnS 2 heterostructure. The low adsorption energy suggests a thermoneutral Gibbs free energy, which facilitates H-H release and recombination reactions. This study provides valuable insights into optimizing hybrid catalysts for enhanced electrocatalytic applications.