Plasmonic Ag-Decorated Few-Layer MoS₂ Nanosheets Vertically Grown on Graphene for Efficient Photoelectrochemical...

A controllable approach that combines surface plasmon resonance and two-dimensional (2D) graphene/MoS₂ heterojunction has not been implemented despite its potential for efficient photoelectrochemical (PEC) water splitting. In this study, plasmonic Ag-decorated 2D MoS₂ nanosheets were vertically grown on graphene substrates in a practical large-scale manner through metalorganic chemical vapor deposition of MoS₂ and thermal evaporation of Ag. The plasmonic Ag-decorated MoS₂ nanosheets on graphene yielded up to 10 times higher photo-to-dark current ratio than MoS₂ nanosheets on indium tin oxide. The significantly enhanced PEC activity could be attributed to the synergetic effects of SPR and favorable graphene/2D MoS₂ heterojunction. Plasmonic Ag nanoparticles not only increased visible-light and near-infrared absorption of 2D MoS₂, but also induced highly amplified local electric field intensity in 2D MoS₂. In addition, the vertically aligned 2D MoS₂ on graphene acted as a desirable heterostructure for efficient separation and transportation of photo-generated carriers. This study provides a promising path for exploiting the full potential of 2D MoS₂ for practical large-scale and efficient PEC water-splitting applications.