▎ 摘　　要

Modulating electronic structure of graphene overlayers is highly demanding for its potential applications in microelectronics, sensors, and catalysis, which however remains a grand challenge. Here, we report electrochemistry-involved treatments to tune the electronic structure of graphene overlayers. Both galvanic corrosion and potential-aided intercalation of H2O were employed to change the graphene/Cu interfaces to graphene/Cu2O/Cu and graphene/H2O/Cu interfaces, respectively. Electronic properties and structural changes of the graphene/Cu interfaces were investigated by X-ray photoelectron spectroscopy, in-situ Raman, and atomic force microscopy. The formed Cu2O interlayer blocks the charge transfer between graphene overlayer and Cu substrate, which turns n-type doping of the as-grown graphene to free-standing state. In contrast, the intercalated H2O interlayer induces much stronger n-type doping in graphene through the electrostatic field effect generated by confined H2O. This work offers efficient but mild methods to modulate the doping state of graphene layers.