Localized surface plasmons (LSPs) of novel metal nanoparticles has distinct electromagnetic interactions with matter compared with the case using far-filed light. The high field gradient near metal nanostructures opens up the possibility for additional transitions beyond those allowed by normal selection rules, enhancing light-matter interactions. Moreover, plasmon-induced ‘hot carriers’ can accelerate chemical reactions. The energy distribution, lifetime, and transfer of ‘hot carriers’ are key factors affecting electrochemical processes. We find that the LSPs of the Au nanodimer structures prepared on defect-free graphene provide highly-confined electromagnetic field to generate holes and electrons with the electrochemical potentials beyond the limit of those under normal light illumination.