Confined migration of hot electrons is presented in nanorods of layered Ag/graphene/TiO2 structure for highly efficient plasmonic photocatalytic water treatment. The light-illuminating titanium dioxide (TiO2) nanorods provide a large amount of high-energy hot electrons for the generation of highly-active superoxide radical (*O2 -) that leads to the degradation of organics in water. Comparison between photocatalytic processing efficiency by photocatalysts with various composite materials were presented based on the preferred propagation path of induced hot electrons that leads to generation of *O2 -. The best results done by Ag/graphene/TiO2 nanorods showed that the sandwiched layer of graphene on TiO2 nanorods collects the induced hot electrons and results in high efficiency photocatalytic reaction.