In this work, an electro-optical device based on a graphene-Ag nanoparticle hybrid is fabricated as the substrate of graphene mediated surface enhanced Raman scattering (G-SERS) manipulated by the gate and bias voltages. Plasmon-exciton coupling promotes co-driven surface catalytic reactions, where the density of states (DOS) of holes and electrons on graphene is well controlled by the gate voltage, and the kinetic energy of holes and electrons is driven by the bias voltage (or current). Our experimental results reveal that the hot holes on graphene mainly contribute to plasmon-exciton co-driven oxidation reactions. The contribution of hot electrons to oxidation reactions is less important. Our novel electro-optical device can be potentially applied in controlling plasmon-exciton co-driven oxidation or reduction reactions by tuning the gate and bias voltages.